salinity effects on the development and larval tolerance

Louisiana State UniversityLSU Digital Commons

LSU Historical Dissertations and Theses Graduate School

1987

Salinity Effects on the Development and LarvalTolerance of Five Species of Echinoderms.Richard Allen RollerLouisiana State University and Agricultural & Mechanical College

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Recommended CitationRoller, Richard Allen, "Salinity Effects on the Development and Larval Tolerance of Five Species of Echinoderms." (1987). LSUHistorical Dissertations and Theses. 4417.https://digitalcommons.lsu.edu/gradschool_disstheses/4417

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Order Num ber 8728218

Salin ity effects on th e developm ent and larval to lerance o f five species of echinoderm s

Roller, Richard Allen, Ph.D.

The Louisiana State University and Agricultural and Mechanical Col., 1987

UMI300 N. Zeeb Rd.Ann Arbor, MI 48106

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UniversityMicrofilms

International

S a l i n i t y E f f e c t s on th e D evelopm ent and L a r v a l T o le ra n c e o f F iv e S p e c ie s o f Echinoderm s

A D i s s e r t a t i o n

S u b m it te d t o t h e G ra d u a te F a c u l t y o f t h e L o u i s i a n a S t a t e U n i v e r s i t y and

A g r i c u l t u r a l and M e ch a n ica l C o l le g e i n p a r t i a l f u l f i l l m e n t o f th e

r e q u i r e m e n ts f o r th e d e g re e o f D o c to r o f P h i lo s o p h y

in

The D epa r tm en t o f Zoology and P h y s io lo g y

byR ic h a rd A l l e n R o l l e r

B .S . U n i v e r s i t y o f A rk a n sas a t L i t t l e Rock, 1980 M.S. L o u i s i a n a S t a t e U n i v e r s i t y , 1983

A u g u s t , 1987

ACKNOWLEDGEMENTS

I w o u ld l i k e t o e x te n d my a p p r e c i a t i o n t o my com m itte

m embers, Dr. E a r l W eid n e r , D r. J o h n F l e e g e r , D r. J o h n C a p r io ,

D r. H a r o ld S i lv e r m a n , and Dr. R o b e r t C arney f o r t h e i r h e l p f u l

a d v i c e a n d c r i t i c i s m s d u r i n g t h e c o u r s e o f my s t u d i e s .

A p p r e c i a t i o n i s a l s o e x te n d e d t o Mike H o l l e y , D r. M a r t in K apper ,

and Dr. Dave G a r to n f o r t h e i r f r i e n d s h i p and a d v i s e .

I am v e r y i n d e b t e d t o D r . R i c h a r d S t ra th m a n n o f t h e

F r i d a y H a rb o r L a b o r a t o r i e s an d t h e U n i v e r s i t y o f W a sh in g to n f o r

h i s a d v i s e d u r i n g t h e c o u r s e o f my r e s e a r c h . 1 a l s o th a n k Dr.

A .O .D. W il lo w s , D i r e c t o r o f t h e F r id a y H a rb o r L a b o r a t o r i e s f o r

p r o v i d i n g l a b o r a t o r y s p a c e an d f u n d in g f o r v a r i o u s p o r t i o n s o f

t h i s r e s e a r c h .

S p e c i a l th a n k s a r e g iv e n t o Dr. J o h n Lynn, A la n Decho, and

N a t a l i e B e rg e ro n f o r b r a v i n g t h e L v t e c h i n u s - I n f e s t e d w a t e r s o f

F l o r i d a and c o l l e c t i n g u r c h i n s f o r me.

T he c o m p l e t i o n o f my g r a d u a t e d e g r e e s w ould h a v e b e e n

I m p o s s i b l e w i t h o u t t h e l o v e , s u p p o r t an d e n c o u ra g e m e n t o f my

p a r e n t s , Mr. and M rs. O.C, R o l l e r o f L i t t l e Rock, A rk a n s a s and

o f my f a t h e r and m o th e r - i n - l a w , Mr. and Mrs. Ray F i s h e r o f B a ton

Rouge, L o u i s i a n a ,

D e e p e s t g r a t i t u d e and th a n k s a r e e x te n d e d t o my a d v i s o r ,

D r . W i l l i a m B. S t i c k l e J r . who p r o v i d e d me w i t h f i n a n c i a l

s u p p o r t , l a b o r a t o r y s p a c e and i n t e l l e c t u a l s t i m u l a t i o n .

1 w ish t o e x p r e s s my h e a r t f e l t g r a t i t u d e and lo v e t o

ii

my w i f e , T i n a F i s h e r R o l l e r f o r h e r p a t i e n c e , l o v e , a n d

u n d e r s t a n d in g d u r in g t h e s e t r y i n g y e a r s .

A l s o , t h a n k ' s Amos.

i l l

TABLE OF CONTENTSPage

ACKNOWLEDGEMENTS..................................................................................................... i i

ABSTRACT........................................................................................................................ v

INTRODUCTION............................................................................................................... v i i

CHAPTER 1 ...................................................................................................................... 1

CHAPTER 2 ...................................................................................................................... 10

SUMMARY.......................................................................................................................... 83

BIBLIOGRAPHY.............................................................................................................. 86

COPYRIGHT PERMISSION........................................................................................... 89

VITA.................................................................................................................................. 90

iv

A B S T R A C T

S a l i n i t y e f f e c t s o n t h e d e v e l o p m e n t a l r a t e s , l a r v a l

t o l e r a n c e s an d v a r i o u s m e t a b o l i c p r o c e s s e s o f f i v e s p e c i e s o f

e c h i n o d e r m s w e r e i n v e s t i g a t e d . D e v e lo p m e n t o f L v t e c h i n u s

v a r l e e a t u s ( L a m a r c k ) , S t r o n g v l o c e n t r o t u s d r o e b a c h i e n s i s (O .F .

M u l l e r , 1 7 7 6 ) , S t r o n g v l o c e n t r o t u s n u r o u r a t u s (S t im p so n , 1 8 5 7 ) ,

S t r o n g v l o c e n t r o t u s p a l l i d u s (G .O . S a r s , 1 8 7 1 ) , and P l s a s t e r

o c h r a c e u s ( B r a n d t , 1 8 3 5 ) l a r v a e w ere o b s e rv e d . D ev e lo p m en ta l

r a t e s and l a r v a l s u r v i v a l t o m etam o rp h o s is o f £• d r o e b a c h i e n s i s

a n d £ . p a l l i d u s v a r i e d d i r e c t l y w i th s a l i n i t y and w ere w e l l

w i t h i n t h e o b s e rv e d s a l i n i t y t o l e r a n c e and d i s t r i b u t i o n a l l i m i t s

f o r t h e a d u l t s .

Fo r e a c h s p e c i e s , embryos and l a r v a e a t lo w e r s a l i n i t i e s

(2 0 , 2 2 .5 , and 2 5 ° /o o ) te n d e d t o d e v e lo p more s lo w ly th a n th o s e

a t h i g h e r s a l i n i t i e s . £ . o c h ra c e u s and S. d r o e b a c h i e n s i s s u r v i v e d

a l l s a l i n i t y t r e a t m e n t s th r o u g h o u t t h e e x p e r i m e n t a l p e r i o d . F j

h y b r i d l a r v a e e x h i b i t e d s a l i n i t y t o l e r a n c e s and d e v e lo p m e n ta l

r a t e s i n t e r m e d i a t e b e t w e e n v a l u e s r e p o r t e d f o r t h e m ore

s t e n o h a l i n e l a r v a e o f £.. p a l l i d u s a n d t h o s e f o r t h e m ore

e u r y h a l i n e l a r v a e o f £.. d r o e b a c h i e n s i s . £ . p u r o u r a t u s l a r v a e

w ere s t e n o h a l i n e and t o l e r a t e d s a l i n i t i e s a s low a s 2 7 .5 ° / o o S .

G onadal n i n h y d r i n p o s i t i v e s u b s t a n c e s w ere s i g n i f i c a n t l y

lo w e r a t 1 7 .5 ° /o o S and c o e lo m ic c a v i t y l a c t i c a c i d v a l u e s w ere

s i g n i f i c a n t l y h i g h e r a t 20 ° /o o S f o r £ . d r o e b a c h i e n s i s an d

p a l 1 l d u s . a l t h o u g h , h i s t o l o g i c a l e x a m i n a t i o n r e v e a l e d no

o b s e r v a b l e d i f f e r e n c e s i n g o n a d a l s t r u c t u r e b e tw e en a d u l t s

a c c l i m a t e d t o h i g h and low s a l i n i t y .

T e m p e r a t u r e a n d s a l i n i t y e f f e c t s o n t h e d e v e lo p m e n t ,

m e t a b o l i c r a t e s , and l a r v a l t o l e r a n c e o f L v te c h in u s v a r l e p a t u s

(Lam arck) w ere a l s o exam ined . D ev e lo p m e n ta l r a t e s and s u r v i v a l

t o m e ta m o rp h o s is o f l a r v a l L- v a r i e g a t u s v a r i e d d i r e c t l y w i t h

s a l i n i t y . R e s p i r a t i o n r a t e s o f I*, v a r l e p a t u s p l u t e i v a r i e d

d i r e c t l y w i th s a l i n i t y and t e m p e r a tu r e ; w h e re a s , e x c r e t i o n r a t e s

v a r i e d d i r e c t l y w i t h t e m p e r a tu r e and i n d i r e c t l y w i t h s a l i n i t y .

0 :N r a t i o s s u g g e s t i n c r e a s e d r e l i a n c e on p r o t e i n c a t a b o l i s m t h u s

i n d i c a t i v e o f p h y s i o l o g i c a l s t r e s s a t 2 7 . 5 ° / o o S . T he b a c k

t r a n s f e r o f j u v e n i l e £.. v a r l e e a t u s t o low s a l i n i t i e s c o r r e l a t e s

w e l l w i t h 28 day LC50 d a t a o f a d u l t s i n d i c a t i n g 1 8 ° /o o t o be

t h e low s a l i n i t y t o l e r a n c e l i m i t o f a d u l t u r c h i n s .

D a ta o b t a i n e d from t h i s s tu d y i n d i c a t e t h a t t h e l a r v a l

t o l e r a n c e s o f e ch in o d e rm s may l i m i t a d u l t d i s t r i b u t i o n s a lo n g

s a l i n i t y g r a d i e n t s .

vi

INTRODUCTION

Echinoderm s have b e e n lo n g c o n s i d e r e d t o be a n e n t i r e l y

m a r in e a s se m b la g e ; how ever , r e c e n t i n v e s t i g a t i o n s h a v e r e v e a l e d

t h a t s e v e r a l s p e c i e s a r e fo u n d i n b r a c k i s h w a t e r and a r e c a p a b le

o f t o l e r a t i n g r e l a t i v e l y w ide f l u c t u a t i o n s i n s a l i n i t y (B in y o n ,

1 9 7 2 ; S t i c k l e a n d D e n o u x , 1976; S a b o u r in and S t i c k l e , 1981;

S h i r l e y and S t i c k l e , 1 9 8 2 ) . The s a l i n i t y e x t r e m e s i n h a b i t a t e d by

s e v e r a l s p e c i e s v a r i e s f r o m 7 . 7 ° / o o S f o r t h e o p h i u r o i d

Q p h io p h r a p m u s f l l o g r a n e u s (T hom as, 1961) t o 6 0 ° /o o S f o r t h e

a s t e r o i d s A s t r o p e c t e n p o l v a c a n t h u s p h r a e m o r u s a n d A s t e r i n a

b u r t o n i ( P r i c e , 1982; a s r e v ie w e d i n S t i c k l e an d D i e h l , 1 9 8 7 ) .

P r e v i o u s l y i t was b e l i e v e d t h a t b r a c k i s h w a t e r p o p u l a t i o n s o f

e c h in o d e rm s were fou n d o n ly i n r e g i o n s , su c h a s t h e B a l t i c and

B la c k S ea , where th e d i l u t i o n o f s e a w a t e r h a s b e e n v e r y g r a d u a l ,

o c c u r r i n g o v e r g e o l o g i c a l epochs (B in y o n , 1966 , 1 9 7 2 ) . R e c e n t ly

ho w ev er , s e v e r a l p o p u l a t i o n s o f e c h in o d e rm s h a v e b e e n fo u n d i n

r e g i o n s s u b j e c t e d t o s e a s o n a l a n d / o r d i u r n a l f l u c t u a t i o n s i n

s a l i n i t y ( S t i c k l e , and Denoux, 1976; D ro u in £ £ f l l . , 1985; S t i c k l e

a n d D i e h l , 1 987 ) .

M arine i n v e r t e b r a t e l a r v a e a r e known t o be more s e n s i t i v e

t o f l u c t u a t i o n s i n e n v i r o n m e n ta l c o n d i t i o n s t h a n a d u l t s an d a r e

t h e r e f o r e c o n s i d e r e d t h e p r e c a r i o u s l i n k i n t h e l i f e c y c l e

( C a l a b r e s e a n d D a v i s , 1 9 7 0 ; W a t t s £ £ & I . , 1982; R o l l e r and

S t i c k l e , 1 9 8 7 ) . T h o r s o n (1950) i d e n t i f i e d s e v e r a l s o u r c e s o f

l a r v a l "w a s ta g e " i n c l u d i n g fo o d a v a i l a b i l i t y a n d t h e d u r a t i o n o f

vii

t i m e i n t h e p l a n k t o n . The l o n g e r a l a r v a e r e m a in s i n t h e

p l a n k t o n , t h e g r e a t e r i t s c h a n c e s o f succum bing t o p r e d a t i o n ,

s t a r v a t i o n , o r d e t r i m e n t a l e n v i r o n m e n t a l c o n d i t i o n s s u c h a s

p o l l u t i o n o r s a l i n i t y a n d t e m p e r a t u r e v a r i a t i o n s . S e v e r a l

i n v e s t i g a t o r s h a v e a l s o f o u n d e c h i n o d e r m l a r v a e t o b e

p a r t i c u l a r l y s e n s i t i v e t o low s a l i n i t y (T h o rso n , 1946; F e n c h e l ,

1 9 6 5 ; W a t t s fi_L. , 1 9 8 2 ) . G e z e l i u s ( 1 9 6 3 ) fo u n d t h a t t h e

c l e a v a g e r a t e o f f e r t i l i z e d Psammechinus m i l i a r i s eggs a t a

g iv e n t e m p e r a tu r e depended on t h e s a l i n i t y t o w hich t h e p a r e n t s

h a d b e e n a d a p te d . Greenwood and B e n n e t t (1981) p e r fo rm e d o s m o t ic

s h o c k e x p e r i m e n t s on t h e s p e rm a to z o a and ova o f P a r a e c h in u s

a n e u l o s u s b y p r e i n c u b a t i n g e a c h a t 45 t e m p e r a t u r e - s a l i n i t y

c o m b i n a t i o n s b e f o r e f e r t i l i z a t i o n u n d e r o p t im a l c o n d i t i o n s f o r

m a x im a l f e r t i l i z a t i o n . T h e y f o u n d t h a t t e m p e r a t u r e h a d t h e

g r e a t e s t e f f e c t on sp e rm a to z o a b u t s a l i n i t y p ro v e d i n j u r i o u s t o

t h e o v a . G ie s e an d F a rm a n fa rm a ia n (1963) found t h a t t h e g a s t r u l a e

o f S t r o n p v l o c e n t r o t u s p u r o u r a t u s t o l e r a t e d and d i f f e r e n t i a t e d i n

t h e same s a l i n i t y r a n g e ( 2 8 - 3 8 .5 ° /o o S ) a s t h a t t o l e r a t e d by th e

eg g s and a d u l t s . W a tts e £ &1. (1982) t r a n s f e r r e d 2 - d a y - o l d t y p e 1

and ty p e 2 l a r v a e o f t h e a s t e r o i d E c h l n a s t e r s p e c i e s com plex t o

t h r e e t e m p e r a t u r e s and t h r e e s a l i n i t i e s and fo u n d t h a t s a l i n i t y

w as t h e d o m in a n t f a c t o r a f f e c t i n g d ev e lo p m en t and g ro w th . F^

h y b r i d s showed i n t e r m e d i a t e deve lopm en t and and g ro w th r e s p o n s e s

a t t h e a p p a r e n t o p t im a l c o n d i t i o n s an d th e y e x h i b i t e d s t r o n g e r

m a t e r n a l c h a r a c t e r i s t i c s . These s t u d i e s s u g g e s t t h a t s a l i n i t y

t o l e r a n c e s and d e v e lo p m e n ta l r a t e s o f e ch in o d e rm l a r v a e c a n be

viii

m o d i f i e d by a c c l i m a t i n g a d u l t s t o r e d u c e d s a l i n i t y and t h a t t h e

o v a a r e m o r e s t r o n g l y i n f l u e n c e d b y lo w s a l i n i t y t h a n

s p e rm a to z o a .

The o b j e c t i v e s o f t h i s r e s e a r c h was t o (1 ) exam ine th e

e f f e c t s o f s a l i n i t y on t h e d e v e lo p m e n t , m e t a b o l i c r a t e s , and

l a r v a l t o l e r a n c e s o f f i v e s p e c i e s o f e c h in o d e rm s w hich a r e fou n d

i n w a t e r s o f v a r y i n g s a l i n i t y ( 2 ) a t t e m p t t o c o r r e l a t e t h e

o b s e r v e d d e v e l o p m e n t a l r a t e s an d t o l e r a n c e s w i t h known a d u l t

d i s t r i b u t i o n s a l o n g s a l i n i t y g r a d i e n t s ; an d (3 ) d e te r m in e i f

t h e r e i s any r e p r o d u c t i v e a d v a n ta g e o r p o t e n t i a l f i t n e s s g a i n i n

a c c l i m a t i n g a d u l t s t o low s a l i n i t y w a t e r s . The s p e c i e s c h o se n

f o r i n v e s t i g a t i o n w ere : t h e g r e e n s e a u r c h i n , S t r o n p v l o c e n t r o t u s

d r o e b a c h i e n s i s : t h e p u r p l e s e a u r c h i n , S t r o n g v l o c e n t r o t u s

p u r p u r a t u s : t h e w h i te s e a u r c h i n , S t r o n g v l o c e n t r o t u s p a l l i d u s :

t h e s e a s t a r , P i s a s t e r o c h r a c e o u s : a n d t h e F l o r i d a u r c h i n ,

L v te c h in u s v a r i e g a t u s . T h is work w i l l f u r t h e r o u r u n d e r s t a n d in g

o f e c h in o d e rm b i o l o g y by y i e l d i n g i n f o r m a t i o n c o n c e r n in g l a r v a l

s a l i n i t y t o l e r a n c e s and t h e i r e f f e c t on a d u l t d i s t r i b u t i o n a lo n g


T h i s d i s s e r t a t i o n i s d i v i d e d i n t o 2 c h a p t e r s . C h a p te r

one i s a r e p r i n t o f a p a p e r p u b l i s h e d i n t h e C a n a d ian J o u r n a l o f

Zoology (Vol 63 , pp . 1531-1538) e n t i t l e d " E f f e c t s o f s a l i n i t y on

l a r v a l t o l e r a n c e and e a r l y d e v e lo p m e n ta l r a t e s o f f o u r s p e c i e s

o f e c h i n o d e r m s " . C h a p t e r 2 i s a m a n u s c r i p t e n t i t l e d "Does

s a l i n i t y a c c l i m a t i o n a f f e c t t h e l a r v a l t o l e r a n c e , p h y s io lo g y ,

and e a r l y d ev e lo p m en t o f S t r o n g v l o c e n t r o t u s d r o e b a c h i e n s i s (O .F .

l x

M u l l e r , 1 7 7 6 ) , £• p a l l i d u s (G.O. S a r s , 1 8 7 1 ) , and L v te c h ln u s

v a r i e e a t u s (Lam arck) (E c h in o d e rm a ta : E c h in o id e a ) ? "

CHAPTER 1

EFFECTS OF SALINITY ON LARVAL TOLERANCE AND EARLY

DEVELOPMENTAL RATES OF FOUR SPECIES OF ECHINODERMS

R e p r i n t e d from : C an ad ian J o u r n a l o f Zoology 6 3 (7 ) :1 5 3 1 -1 5 3 8 (1985)

2

Effects of salinity on larval tolerance and early developmental rates of four species ofechinoderms

R i c h a r d A . R o l l e r a n d W i l l i a m B. S t i c k l e

Department o f Zoology and Physiology, Louisiana State University, Baton Rouge. LA. U.S.A. 70803

Received September 18. 1984

Roller, K. A ., and W . B. STICKLE. 1983. Effects o f salinity on Isrval (olennce and early developmental rales o r Tour species ofechinodenro. Can. J. Zool. <3: 1331-1338.

Larval lolerances and developmental rates of four species and one hybrid cross o f echinoderms were determined as a function of salinity. Fertilization and development o f Slrongylocentrotus droebachiensis (O.F. Muller. 1776), Strongylocemrotus purpuratus (Stimpson. 1837), Strongylocemrotus pallidus (G.O. Sors, 1871). snd Pisaster ochraceus (Brandt, 1833) larvae were observed. A hybrid was created by fertilizing eggs o f S. droebachiensis with sperm from S. pallidus. Fertilized eggs were placed in filtered, natural seawater <3(rX— S) diluted lo 30. 27.3, 23, 22.3, and 20%. S and cleavage and larval development were observed over 32 days. Developmental rales differed among salinity treatments within each species. For each species, embryos and larvae at lower salinities (20, 22.3, and 23%. S) tended lo develop more slowly than those ul higher salinities (27.3 and 30%. S). Pisaster ochraceus and S- droebachiensis larvae survived all salinity treatments throughout the experimental period. The hybrid larvae exhibited salinity tolerances and developmental rates Intermediate between values reported for the more stenohaline larvae o f S. pallidus and those for the more euryhaline larvae of S. droebachiensis. The interaction of a secondary stressor (food availability) with salinity was examined; algal concentration did not influence the survival, developmental rate, or length of P . ochraceus or S. droebachiensis larvae.

R o l l e r , R. A ., c t W . B. S t ic k l e , 1983. E ffe c ts o f sa lin ity o n larva l to le ran ce an d e a rly d ev e lo p m en ta l ra te s o f fo u r sp ec ie s or e c h in o d e rm s . Con. J. Z o o l. 63: 1 3 3 1 - 1 3 3 8 .

La toldrance larvairc 8 la satinifd et Ic laux de ddvcloppcmcnt en fonction dc la salinild ont fait 1‘objct d'unc dtudc ebez quatrc espbees et un hybride d'behinodermes. La fdcondation ct Ic ddvcloppcmcnt ont did dtudids chcz dcs larves dc Slrongylo- centrotus droebachiensis (O.F. Miller, 1776), dc Strtmgylocentrnlus purpuratus (Stimpson, 1837), de Strongylucenlrotus pallidus (G.O, Sors, 1871), ct dc Pisaster othraceus (Brandt, 1835). La fdcundulion d'ocufs dc S. droebachiensis par du spermc de S. pallidus a donnd lieu 8 un hybride. Les ocufs fdcondds ont did placds dans de 1'cau dc mer noturellc fittrdc (30%,) dilude 8 3 0 ,2 7 ,5 , 25, 22,5 et 20%.. La division el le ddvcloppcmcnt larvairc ont ensuite did suivis durant 32 jours. La vitesse du ddvcloppcmenl larvairc voriait cn fonction dc la salinild chcz loutcs les espiccs: les cmbryons ct les larves avaicnt tendance 8 sc ddvclopper moins vile aux salinilds les plus faibles (20 ,22 ,5 et 23% ) qu'aux salinilds les plus fortes (27,5 et 30% ). Les larves de P. ochraceus ct de S. droebachiensis onl survdcu durant toutc I'cxpdrience 8 toutes les salinilds. Les larves hybridcs ont manifcstd unc toldrancc 8 la salinild cl un taux de ddvcloppcmcnt inlcrmddiuircs cnlrc les valours obtcnucs chcz les larves plus stdnohalines de S . pallidus el les larves plus eury halincs de S. droebachiensis. L'oddilion d'un factcur de stress sccondairc (la disponibilitd de la nourriture) a rdvdld que la concentration dcs algues n'influencc ni la survie, ni le laux de ddvcloppcmcnt ou la longueur dcs larves dc P. ochraceus ou dc S. droebachiensis.

[Traduit par le journal]

IntroductionAlthough the phylum Echinodermata is well-known as an

exclusively marine assemblage, populations o f a number o f species have been found in brackish water habitats (Binyon 1966, 1972; Thomas 1961; Stickle and Denoux 1976; Slancyk and Shaffer 1977; Turner and Meyer 1980; Pagelt 1978; Himmelmann el al. 1983). The distribution o f echinoderms along salinity gradients is believed lo be limiied because they possess a permeable body wall and lack differentiated osmoregulatory and excretory organs (Binyon 1966, 1972). In addition, within the zone o f tolerance, the energy budget of Leptasterias hexactls was found to vary directly with environmental salinity (S) so that an average-wcight starfish accmed 14.7 cal/day (1 cal = 4.1868 J) at 30% S and 2.9 cal/day at 20 % S but lost 10.7 cal/day at 15% S (Shirley and Stickle 1982a, 1982b).

Stickle and Denoux (1976) have shown that populations o f four species o f echinoderms from the glacier influenced region o f the Lynn Canal in southeastern Alaska tolerated fluctuating salinity during the summer months when the amplitude o f salinity variation ranged from 11.4 to 17.2% during semidiurnal tidal cycles. Comparisons o f the salinity tolerance of the benthic stage o f three species o f echinoderms from the Alaskan populations (Sabourin and Stickle 1981; Shirley and

Stickle 1982a) with that o f populations o f those species from the high salinity environment near Friday Harbor, WA have shown that the populations o f Eupentacta quinquesemita and Leptasterias hexactls from the low salinity environment are more tolerant o f low salinity than populations from Friday Harbor (Stickle et a l .1). No significant difference existed between the salinity tolerances o f the two populations o f benthic Slrongylocentrotus droebachiensis.

Several investigators have shown echinoderm larvae lo be particularly sensitive lo low salinity (Thorson 1946; Fenchel 1963; Binyon 1972; Watts el a l. 1982). This project was designed to determine the effects o f salinity on the tolerance and developmental rates o f one species o f asteroid (P isas- ter ochraceus (Brandt, 1833)), three species o f echinoids (Slrongylocentrotus droebachiensis (O. F. Muller, 1776), Slrongylocentrotus purpuratus (Stimpson, 1837), and Slron- gylocentrotus pallidus (G. O. Sars, 1871)), and one hybrid (S. droebachiensis( 9 ) X S. pallidus ( 6) ) from Friday Harbor, WA, a high-salinity environment. The rationale for using the hybrid cross is to attempt to determine the role that a species'

'Stickle, W. B ., M. Rotcnbciry. and D. Follz. Population differences in the salinity tolerance, activity coefficients, and genetic composition o f three species of echinoderms. Submitted for publication.

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Flo. I. San Juan Archipelago; inset, collection site on San Juan Island,

genetic makeup plays in the adaptation to salinity gradients. The determination o f the salinity tolerance and growth or both the larval and benthic stages in the life cycle o f these echinoderms will provide insight into the selective forces that salinity gradients place on these species o f echinoderms.

Materials and methodsMature adults of four echinoderm species were collected from San

Juan Island, WA (U .S.A .) during May 1984 (Fig. I). Adult Pisaster ochraceus and Slrongylocentrotus purpuratus were collected during low tide at Lime Kiln Light on the west side o f San Juan Island. Strongylocemrotus droebachiensis was collected during low tide at Cattle Point, on the southwestern tip o f San Juan Island. Strongylocen- Iroluspallidus was collected al 7 0 -9 0 m depth during a dredging trip on the R /V N ugget in San Juan channel. All specimens were relumed to the Friday Harbor laboratories and maintained in a running seawater system.

Water temperature and salinity measurements in the seawater system were taken daily and both showed slight variation during the 32-day experimental period. Water temperature ranged from 9.0 to 11.0*C ( i ± SE = 9.9 ± 0. IU“C; n =■ 32) and salinity ranged from 30.0 to 32'/.. S (30.S i 0 .1 '/.. S; n * 32). Little seasonal variation occurs in the salinity o f the waters surrounding San Juan Island. In a 3-year study of seasonal variations in surface temperature and salinity at the Friday Harbor laboratory, Phifer and Thompson (1937) found mean monthly salinity to vary from 2 9 .7 /» in July to 30.7 '/.. in October. Furthermore, the water mass was nearly homogenous in salinity lo a depth of 100 m.

Male and female S. droebachiensis, S , purpuratus, and S . pallidus were induced to spawn by eoelomic injection with approximately 2 mL of 0.3 M KCI (Stralhmann 1974), Female P. ochraceus were dissected, and ovarian maturation was induced by immersion in a 10'* M solution of 1-mclhyladcninc in seawater (Stevens 1970; Stralhmann and Vcdder 1977). All eggs were washed in filtered seawater and were fertilized with sperm from males o r the same species. In the case of P. ochraceus, the testes were dissected from the adult to obtain sperm. A hybrid cross was created by fertilizing eggs of S . droebachiensis

with sperm ftum S . pallidus (Stralhmann 1981). The percent fertilization for each species was as follows: S. droebachiensis, 98%; S . purpuratus, 91%; S . pallidus, 90%; hybrid, 88%; P. ochraceus, 94%. The criteria used in determining the success o r fertilization were the formation o f the fertilization envelope and the first cleavage of the zygote.

Two hundred fertilized eggs from each species were placed in 200 mL of filtered (1.0 p.m) seawater at each of the following salinities: 30, 27.3, 25, 22.5, and 20%. (temperature was 9.9 ± 0 .10*C (£ ± SE); n - 32). Developing embryos and larvae were maintained at these salinities throughout the experimental period. The water in each culture was changed daily during the course of the experiment. When the bipinnaria or pluteus stage was reached the larvae were fed Dunaliella teniolecta daily.

During the early cleavage stages the cultures were examined hourly to determine developmental rales. After the swimming larval stage (bipinnaria or pluteus) was reached, the cultures were examined daily. A sample of 10 embryos or larvae was examined for the determination o f developmental rates. Since mortality of all of the embryos or larvae in a culture of a particular salinity occurred within a very narrow time span (hours), we were unable to obtain an estimate of percent survival for any culture to u given stage. Survival was instead expressed as the number of days to which the embryos ur larvae of a particular culture survived after fertilization. Length and width measurements (Fig. 2) were made on all-embryos and larvae al each examination with an ocular micrometer. For cchinoplutci, two length measurements were made: total length ( i ) was the distance from the posterior tip o f the pluteus to the lip o f the postoral arms; and midlinc length (£ ') was the distance from the posterior lip to the postural transverse ciliated band. Width measurements for the plutci were taken at the most posterior extent of the ciliated band, dorsal to the postoral arms.

The interaction o f a secondary stressor (low food availability) with salinity was examined for P. ochraceus by first dividing the cultures in half. One-half o f the blpinnariac o f P. ochraceus were fed a relatively high concentration o f D, tertiolecla (6000 cells/mL) which permits maximum ingestion by (Stralhmann 1971) and maximum growth of (Lucas 1932) some asteroid larvae. The other half of each P. ochraceus culture was fed a concentration of algnc (500 cells/mL)

ROLLER AND STICKLE

a bF ig . 2 . D iag ram illu s tra tin g m easurem ent* o r (a ) p lu te i o f Strongy-

locenlroius droebachiensis an d (t>) b ip in n a ria o f Pisaster ochraceus. L, to ta l len g th o f la rv ae ; L \ m id lin e leng th ; tV, w id th o f larvae.

well below the oatialion concentration. This experiment was repeated for the S. droebachiensis cultures. Two-way analysis o f variance (ANOVA) (Anonymous 1982) was used to determine significant variation among treatments, with tests of salinity and algal concentration main effects as well as their interaction. Scheffc’s test (Sncdccor and Cochran 1980) was used lo identify which treatments were significantly different from each other in the larval size experiments as a function of salinity and algal ration. Regression analyses were conducted using a general linear model (GLM) procedure (Anonymous 1982). Significance is reported for the f-tcsl of model versus error sums o f squares in this analysis of regression. The coefficient of determination (r ‘ ) values (Steel and Tonic 1980) ate from the fit of these linear regression models.

ResultsSurvival

Considerable variation exists in the salinity tolerance o f the four species o f echinoderm larvae, and the hybrid cross (Table I). The larvae of 5 . droebachiensis and P. ochraceus survived the 32-day exposure at all experimental salinities; he wever, the embtyos and bipinnariac of P. ochraceus at 20%, £ were very abnormal by the 32nd day compared with those at higher salinities (Figs. 3 - 6 ) . The plutei o f S. droebachiensis maintained at all o f the experimental salinities were normal in appearance (Figs. 7 and 8).

For S. pallidus and S . purpuratus only larvae maintained at 27.5 and 30%, S survived the 32-day experimental period. The length of survival o f larvae increased with increasing environmental salinity for both species. The hybrid plutei were normal in appearance at all salinities above and including 22.5% (Fig. 9). The survival data for S. purpuratus and S . pallidus at 20, 22.5, and 25%, S represent conservative estimates because there were many deformed larvae still moving during the early days o f the experimental period. Hybrid larvae from the S. droebachiensis ( 9 ) - S. pallidus ( d ) cross exhibited salinity tolerances that were intermediate between those of the two species.

Developmental ratesDevelopmental rales increased directly with increasing

salinity for larvae o f all four echinoderm species and the hybrid cross. The developmental rate o f P. ochraceus larvae was slower at 20, 22.5, and 25%, S in comparison with larvae cultured at 27.5 and 30%, S (Table 2). The presence o f abnormal gastrulae al 20%, S after 4 days exposure suggests that larvae cultured at 22.5 and 25%, S may also not develop nor*

T a b l e 1. S u rv iv a l tim e (d ay s) o s a fu n ctio n o f salin ity

Species

Salinity (%,)

20 22.5 25 27.5 30

P. ochraceus >32* > 32 >32 >32 >32S. droebachiensis >32 > 32 >32 >32 >32Hybrid 2 >32 >32 > 32 >32S. pallidus 1.3 1.5 7 >32 >32S. purpuratus 2 2.5 9 >32 >32

*Ab*ofiMl Iw tc ,

T ab le 2. Salinity influence on developmental rates for Pisaster ochraceus ate given as elapsed time to each developmental stage

Salinity (%.)

Stage 20 22.5 25 27.5 30

Two polar bodies 2 h 2 h 2 h 2 h 2 h8 -1 6 cell 15 h 15 h 12 h 12 h 12 hUnhalchcd

blastula 49 h 40 h 36 h 18 h 18 hHatching 70 h 48 h 42 h 36 h 36 hGosinila* 96 h 62 h 59 h 49 h 49 hBipinnoriat

with hydrocoel ♦ 10 days 7 days 6 days 6 days

*Buljr kn|th/«thcnlcron length U 3/1. t640 p m in total k ftp h .{Abnormal Urrae, 400 pm in length.

malty because of slower developmental rates relative to the developmental rates o f larvae at 27.5 and 30%, S.

The developmental rale o f the echinoid S. droebachiensis showed no evidence o f a salinity effect through the prism stage but development to the four-arm pluteus stage was slowed in larvae cultured at 20 and 22.5%, S (Table 3). In contrast there was a marked effect of salinity on the developmental rate of S. pallidus during the early stages o f development (Table 4). Furthermore, delayed development of the early stages of S. pallidus was correlated with larval mortality at those salinities during later developmental stages (Table I).

The developmental rates o f 5. droebachiensis ( 2 ) - S. pallidus (cf) hybrid larvae were intermediate between the developmental rates o f the parental species (Table 5). Normal developmental times were lengthened at 22.5%, for the hybrid, compared with developmental times at 25, 27.5, and 30%, S for S . droebachiensis but the hybrid developed normally at a salinity (22.5%,) that was 5%, lower than the salinity at which S. pallidus developed normally.

The developmental rate o f S . purpuratus larvae was greatly lengthened at 20 ,22 .5 , and 25%, S compared with rates at 27.5 and 3 0 % S (Table 6). Furthermore, slower developmental rates were correlated with eventual mortality o f larvae at 20, 22.5, and 25%, S (Table 1).

Algal concentrationAlgal concentration had no effect on larval size of cither

P. ochraceus or S. droebachiensis according to a two-way ANOVA with algal concentration and salinity as main effects. There were, however, significant effects o f salinity on the larval size o f both species. Since larval length and width measurements of both species yielded the same pattern when measurements were made on day 30 (Table 7) and no signifl-

FIG. 3. Norm*] blu lu l* o f Pisaster ochraceus cultured in 30%, S seawater (18 h postfertilization). F, fertilization envelope; P . petivilellinc space; B, blistocoel; arrows indicate margin of blastocoel. B o. 4 . Abnormal blastula o f Pisaster ochraceus cultured in 20%. S seawater (49 h postfertilization). F , fertilization envelope; P. pcrivitelline space; arrow, malformed cells. F ig . 3. Ventrolateral view o f abnormal Pisaster ochraceus bipinnaria in 20%> S seawater (2 weeks postfertilization). M, mouth; S, stomach. Note absence of preoral and anal loop dilation. F ig . 6. Ventral view of normal bipinnaria o f Pisaster ochraceus in 30/6. S seawater (6 days postfertilization). A , anal lobe; Al, anal loop cilia; B, blastopore (anus); C , left coelom; E, esophagus; In, intestine; M, mouth; P, preoral lobe; PI, preoral loop ciliation; S , stomach.

T a b l e 3 . Salinity influence on developmental rates for Slrongylo- ceturotus droebachiensis is given as elapsed lime to each stage

Salinity (%.)

Stage 20 22.5 25 27.5 30

S cell 7 h 7 h 6 h 6 h 6 h16 cell 8 h 8 h 7 h 7 h 7 hUnhatched

blastula 18 h 18 h 18 h 18 h 18 hPrism 3 days 3 days 3 days 3 days 3 daysFour arm*

pluteus 7 days 7 days 6 days 5 days 5 daysFour arm t

pluteus 9 days 9 days 7 days 7 days 7 daysT o u t tcn|Ul ta SQO |u n . t Vestibule present -

cant differences existed between larvae maintained al Duna- tiella tertiolecla concentrations o f 300 or 6000 cells/m L, length measurements are given for both species at 6000 algal cells/m L only (Fig. 10). The larval length o f both species fed 6000 cells/m L varied directly with ambient salinity as evidenced by significant ( r3) linear regressions o f larval length on salinity, and larvae maintained al 20%, S were significantly smaller than (hose maintained at all higher salinities (Scheffe's test). The regression equation for P. ochraceus is given as length (pm ) = -1 0 5 + (salinity x 30.24) (r1 = 0,736; n = 50; p < 0.001) and the equation for S. droebachiensis is length

T a b l e 4. Salinity influence on developmental rates for Slrongylo- centrotus pallidus is given as elapsed time to each stage

Salinity (%>)

Stage 20 22.5 25 27.5 30

8 cell 10 h 6 h 6 h 6 h 6 hUnhatched

blastula 36 h 36 h 20 h 20 h 20 hCastmls* — t — 48 h 45 h 45 hPrism — — 4 days 3 days 3 daysFour arm t

pluteus — — 6 days 6 days

•Body kfifth/irchciMCRin in 2 /1 .t —, tk id culture.iT«U) bod/ length u 300 pm.

(pm ) = 244 + (salinity x 14.97) ( r3 = 0,601; n = 50; p < 0.001). As indicated earlier many of the starfish bipinnariae cultured al 20%, S were abnormal and eventually died.

DiscussionThe pelagic periods of all four species o f echinoderm stud

ied suggest the potential for extensive dispersal in nature (Stralhmann 1978). The shorl-tcmi slcnohulinity of the larval stages o f S. pallidus and S. purpuratus likely limits (hose species to high salinity waters whereas salinity as low as 20%, S does not appear to be as great a selective force affecting the distribution o f (he larval stages o f P. ochraceus or S. droe-

T a b l e S . S a lin ity in flu en ce o n d ev e lo p m en ta l ra le s fo r h y b rid b etw e e n a 9S . droebachiensis an d a <SS. pallidus is g iv en as e lap sed

tim e lo each dev elo p m en ta l stage

Salinity (%,)

Stage 20 22.5 25 27.5 30

16 cell Unhalchcd

20 h 7 h 7 h 7 h 7 h

blastula _• 24 h 20 h 20 h 20 hGaslrutat _ 26 h 24 h 24 h 24 hPrism Four arm

— 4 days 3 days 3 days 3 days

pluteust — 6 days 4 days 4 days 4 days

*— . 4t*U cv tam .tbody fanlh/uthem eron length it 2/1. iToUl body length b 400 tun.

T a b l e 6 . S a lin ity in flu e n ce o n d ev e lo p m en ta l ra tes fo r Strongylo- centrotus purpuratus is g iv en as e lap sed tim e to each stage

Salinity (%.)

Stage 20 22.5 25 27.5 30

16 cell 20 h 10 h 6 h 6 h 6 hUnhatched

blastula _* — 20 h 20 h 20 hPrism — — 6 days 3 days 3 daysFour arm

pluteus — — 8 daysf 5 days 5 daysFour armf

pluteus — — — 8 days 8 days

*—. dead culturetVeiy detonned but Util living larvjc. SVcuibulc present.

bachiensis.Although Pisaster ochraceus larvae survived the entire

salinity range to which they were exposed, larval developmental rates were slower at 20 and 22.5%, S and bipinnaria were abnormal in appearance and smaller at 20%> S, which suggests that they would eventually die. Less than half of the pelagic larval period, found by Sliathmann (1978) to last between 76 and 228 days, had elapsed by the end o f the 32-day experimental period. The dominant carnivore on the lower rocky inienida! community of the outer Pacific coast of North America is P. ochraceus (Paine 1966), found from Silka, AK to Cedros Island, Baja California (Lambert 1981; Morris et al. 1980). In the inside waters o f the British Columbia coast, and in lower Puget Sound, Pisaster is replaced by Evasterias troschelii (Lambert 1981). Fifty-seven P. ochraceus were

Flo. 7. Ventral view o f noimal pluteus of Slrongylocentrotus droebachiensis in 30%, S seawater (5 days postfcnilization). A, anterolateral arms; E, esophagus; In. intestine; M. mouth; P, postoral arms; Pd, postcrodorsal aims; S , stomach; Sr, skeletal rods. Ftc. 8. Ventral view of normal pluteus of Slrongylocentrotus droebachiensis in 20%, S seawater (7 days postfertilization). A, anterolateral arms; E, esophagus; M, mouth; P, posloml arms; Pd, postcrodorsal arms; S, stomach; Sr, skeletal rods. Ftc. 9. Dorsal view of healthy hybrid (S. droebachiensis ( 9 ) x S. pallidus (d ) ) pluteus in 22.5%, S seawater (6 days postfertilization). A, anterolateral aims; E, esophagus; M, mouth; P, postoral arms; Pd, postcrodorsal arms; S, stomach; Sr, skeletal rods.

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E=L

800

700

600X f—CD 500LU

§cr<

400

700

P. ochraceus

D

- S. droebachiensis

6 0 0 -

500

0 20 25 30SALINITY (%o)

Fig. 10. Length o f Pisaster ochraceus bipinnarii end Slrongylo- centrotus droebachiensis plutei after 30 days exposure i t environ- menlil salinities o f 20, 22.5, 25, 27.5, and 30%. in the presence of 6.0 x 10' D umlieiia tertiolecta per millilitre. Mean lenglhs IN “ 10) arc plotted for each salinity and tellers near each data point indicate Scheffe's groupings; data points sharing the same letter arc not significantly different from each other. Regression of larval length as a function of salinity is also plotted.

recovered two summers after 87 adults from a high-salinity habitat (Prince William Sound, south-central Alaska) were transplanted to a low-salinity (as low as 12.5%) habitat (Auke Bay, AK) (W. B. Stickle and C. B. O’Clair, personal observation). No juveniles were recovered, however, which suggests that either P. ochraceus are incapable or reproducing al that location or the larval stages will not tolerate reduced salinity.

Larval survival o f S . droebachiensis was unaffected by 32 days exposure lo the entire 20 -30% , S range of our experimental design but normal development to the four-arm pluteus stage was slower at 20 and 22.5% S than at 25, 27.5, and 30% S and there was a direct relationship between larval size at 30 days and salinity. The planktonic larval stage o f the green sea urchin cultured at 30% S at Friday Harbor varies from 51 to 152 days (Stralhmann 1978). The habitat o f the benthic stage o f S. droebachiensis is circumpolar and green sea urchins from both the low and high salinity environments near Juneau, AK and Friday Harbor tolerate environmental salinities as low as 13% S (Sabourin and Stickle 1981; Stickle el at. sec footnote 1).

The hybrid-cross experiment between a female S. droebachiensis and a male S . pallidus supports the contention that there is a genetic component to the euryhalinity o f S . droebachiensis. Hybrid larvae exhibited survival and develop

mental rate patterns intermediate between those o r the two parental species. The conclusion would be stronger if the same observations had been made for the reciprocal cross (paternal S. droebachiensis) but with this cross the percent fertilization is near zero (Stralhmann 1981). The reciprocal cross, if feasible, and backcrosses between the F, hybrids and both species would allow further clarification of the genetic component o f euryhalinity in S. droebachiensis.

Larval tolerance and developmental rates of S. purpuratus and S . pallidus correlate well with the distributional pattern of the adult stages. Slrongylocentrotus purpuratus occurs from Alaska to Baja California, along the outer coast of British Columbia and Alaska (Ricketts and Calvin 1968) and is only encountered in the Puget Sound region on shores that are somewhat exposed to strong wave action such as the western side of San Juan Island (Kozloff 1983). Therefore, benthic urchins are not exposed lo brackish water. Larvae arc likely limited to salinities greater than 25% if stow developmental rates at 20, 22.5, and 25% are indicative o f eventual larval mortality during the later stages o f development. Giese and Farman- farmaian (1963) determined that the 35-day tolerance limit of S . purpuratus is 29% S and that the low salinity larval tolerance is 28% ; their larval tolerance limit agrees very well with our value o f 2 5 -2 7 .5 % S. Likewise, S. pallidus are usually restricted to depths greater than 50 m in the San Juan Archipelago (Kozloff 1974) where ambient salinity is always greater than 30% (Thomson 1981; Collias el al. 1974). The results of this investigation indicate that the larval stages of both S. purpuratus and S. pallidus are stenohaline and limited to salinities greater than 27.5% . Larval developmental times through settling at 30% S are considerably longer than the 32-day experimental period of this study: 6 3 -8 6 days for S . purpuratus and 63 days for S. pallidus (Stralhmann 1978). R. R. Stralhmann (personal communication) has indicated that the species used in this investigation could possibly be reared in a shorter time than previously reported (Stralhmann 1978).

Differences in food availability had no visible effect on the developmental rates, survival, or larval size of either P. ochraceus o r S. droebachiensis as a function of salinity. Two possibilities exist for the lack o f a statistical relationship between the algal ration o f Dunatiella tertiolecta provided to P. ochraceus and S. droebachiensis and their larval length or width after 30 days exposure to a salinity gradient (Table 7). Both algal concentrations, 500 and 6000 cells/m L, may be higher than the concentration necessary to saturate the feeding mechanism o f the larvae. Alternatively, algae may not be necessary to accomplish development through the first 30 days o f the planktonic phase o f the life cycle for either species.

The direct relationship between larval size and ambient salinity after 30 days exposure may be due lo variation in either the rate o f energy acquisition or metabolic maintenance costs. Stickle (1985) has found that variation in energy acquisition along gradients o f environmental factors is much more important than variation in metabolic maintenance costs for five species or carnivorous marine invertebrates but we do not know if this finding is also valid for planktonic larvae. It is likely that the interaction between the availability o f food and salinity would be important during later, critical stages of development such as settlement and metamorphosis.

The geographic area over which larvae are dispersed from a resident population can greatly influence the genetic composition o f isolated populations o f echinoderms. The duration o f the planktonic phase o f a species as well as larval behavioral

8

T a b l e 7. Anslysis of variance table of Strongylocemrotus droebachiensis and Pisaster ochraceuscultured312 0 .2 2 .5 .25,27.5, or 30%. S for 32 days and provided DuW/W/n

tertiolecta at concentrations o f 500 or 5000 cclls/mL

Species Source dr MS F

S, droebachiensis Total 99Food 1 154/1232 0.08NS/0.9INS

Salinity 4 98257/53310 5l.93*»/39.50**Food x salinity 4 6)8/1341 0.33NS/0.99NS

Error 90 1892/1350

P. ochraceus Total 99Food 1 615/1592 0.93NS/2.45NS

Salinity 4 347982/144174 527.I6** /22I.72«Food x salinity 4 1601/1558 2.42N5/2.40NS

Error 90 660/650

Non;: Luvsl knglh/whlth meatuicmcnu wen nude u itwwn in Fig. 2 end given in mkrumclnre. NS indieem ncnsignifKun effects il lt»c p 2 0.03 level; ' 1 indiceles/i < 0.001.

characteristics influence the degree o f dispersal and adaptation of isolated populations of a species to local environmental conditions (Burton and Feldman 1982). Echinoderm larvae ate not thought to utilize behavioral patterns to maintain their position in a geographic area, as crustaceans do (Cronin and Forward 1982). Stralhmann (1982) concluded on theoretical grounds that Ihc large-scale spread or larvae from a given population is an accidenial though important consequence o f a long planktonic period, but the spread of offspring confers no short-term advantage to that population. Large-scale larval dispersion between populations if associated with increased genetic variability may, however, increase the frequency of polymorphic loci in each population and increase the physiological fitness o f those individuals that contain a large number of heterozygous alleles at those loci (Garton 1984; Garton et al. 1984; Garton and Stickle 1985). Large-scale spread of S. droebachiensis larvae could account for the euryhalinity of a population o f green sea urchins from the high salinity environment near Friday Harbor (Stickle et a l., see footnote I). However, this process docs not appear to be operative for the other echinoderm species studied in which local selection may limit the species to near full-slrcnglh salinity.

Experimental design strongly influences the results obtained with respect to salinity tolerance and development o f echinoderm larvae along salinity gradients. The present experiment was designed to determine the tolerance and developmental capabilities o f fertilized ova upon transfer from full-sirenglh seawater (30% S), to which the parents were acclimitizcd, lo ambient salinities o f 20, 22.5, 25, 27.5, and 30%° S. Gezelius (1963) found that the cleavage rate of fertilized Psam- mechinus miliaris eggs at a given temperature depended on the salinity to which the parents had been adapted. Greenwood and Bennett (1981) performed osmotic shock experiments on the spcrmatazoa and ova of Parechinus angulosus by preincu- bating each at 45 temperature-salinity combinations before fertilization under conditions o f temperature (15°C) and salinity (34%, S) optimal for maximum fertilization. Temperature gradiants had the greatest effect on spermatozoa but salinity gradiants proved injurious to the ova. Giese and Farman- farmaian (1963) found that the gastrulae o f Slrongylocentrotus purpuratus tolerated and differentiated in the same salinity range (28-38 .5% , S) as that tolerated by the eggs and adults. Watts et al. (1982) transferred 2-day-old type I and type 2 larvae of the asteroid Echinaster species complex lo three tem

peratures and three salinities. They found that salinity was Ihc dominant factor affecting development and growth. Hybrids showed intermediate development and growth responses at the apparent optimal conditions. Hybrids also exhibited stronger maternal characteristics. Most larval mortality occurred after the mouth was formed. These studies indicate that Ihc salinity tolerance und developmental rule of echinoderm larvuc can tic modified by acclimating adults to reduced salinity and that ova are more strongly influenced by low salinity than spermatozoa. Only properly designed experiments which control for the acclimation history and genetic composition of parents will allow for a completely ecologically meaningful characterization o f larval tolerance and developmental rates along salinity gradients.

The stenohalinity o f the pelagic larval stages or Strongy- locentrotus purpuratus and S, pallidus likely limit the distributional patterns o f these sea urchins. Our experiments are inconclusive with respect to the correlation between the effects o f salinity on the larval tolerance and developmental rates of P. ochraceus and adult distributional patterns in estuarine waters. Larval survival and developmental rates are well correlated with the euryhalinity o f S. droebachiensis. Future research will compare results obtained with populations adapted to high salinity to those o f populations subjected in nature to fluctuating salinity which may have been influenced by local environmental selection.

AcknowledgementsWe thank Dr. A .O.D. Willows, Director of the Friday

Harbor laboratories, for facilities and financial assistance during the course o f the investigation. A scholarship was provided lo assist one of us (Roller) in attending the Larval Ecology course at the Friday Harbor laboratories during the spring term of 1984. Appreciation is extended to Dr. Richard R. Stralhmann, Dr. John W. Lynn, Dr. David W. Garton, and M. A. Rapper for reviewing and correcting parts o f the manuscript. H. Thompson aided in the statistical analysis and M. Had field provided valuable advice at various stages in the study. Special thanks arc extended to Tina F. Roller for the drawings and graphs. This investigation was funded in part by grams from Ihc Petroleum Refiners Environmental Council of Louisiana (PRECOL) and the Organizalional Relief Fund (ORF) o f Louisiana Slate University.

9

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C o l u a s . E. E ., N. M c G a r y , and C. A. B a r n e s . 1974. Allas of physical and chemical properties of Puget Sound and its approaches. University o f Washington Press, Seattle, WA.

C r o n i n , T. W .. and R. B. F o r w a r d , J r . 1982. Tidally limed behaviors: their effects on larval distributions in estuaries. In Estuarine comparisons. Edited by V. S. Kennedy. Academic Press, New York. pp. 505-320 .

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C a r t o n , D. W „ R. K. K o e h n . and T. M. S c o n . 1984. Multiple locus heterozygosity and the physiological energetics o f growth in the coot clam, Mulinia lateralis, from a natural population. Ccnclics, 108: 445-455 .

C a r t o n , D. W ., and W. B. S t i c k l e . 1985. Relationship between multiple locus heterozygosity and fitness in the gastropods Thais haemastoma and T. tamellasa. In Marine biology of polar regions and effects of stress on marine organisms. Edited by S. S. Cray and M. E, Christiansen. John Wiley & Sons, New York. pp. 543-553.

GEZEUUS, C. 1963. Adaptation of the sea urchin Psammechinus miliaris to different salinities. Zool. Bidr. Uppsala, 35: 329-337.

G iese, A. C ., and A. F a r m a n f a r m a i a n . 1963. Resistance of the purple sea urchin lo osmotic stress. Biol. Bull. (Woods Hole, M ass.), 124: 182-192.

G r e e n w o o d , P. J., andT . B e n n e t t . 1981. Some effects o f temperature-salinily combinations on Ihc early development of the sca urchin Parechinus angulosus (Leslie). Fertilization. J. Exp. Mar. Biol. Ecol. 51: 119-131.

H im m e lm a n , J . H , Y. L a v e r c n e . F. A x e l s e n , A. C a r d i n a l , and E. B o u r c e t . 1983. Sea urchins in the St. Lawrence estuary Canada, their abundance, size structure and suitability for commercial exploitation. Can. J. Fish. Aquat. Sci. 40: 474-486.

K o z l o f f , E . N . 1974. Keys to the marine invertebrates of Puget Sound, the San Juan Archipelago, and adjacent regions. University o f Washington Press, Seattle, WA.

1983. Seashore life o f the northern Pacific coast. An illustrated guide lo northern California, Oregon, Washington and British Columbia. University of Washington Press, Seattle, WA.

L a m b e r t , P. 1981. The sea stars of British Columbia. Handbook 39. British Columbia Provincial Museum, Victoria.

Lucas, J. S. 1982. Quantitative studies o f feeding and nutrition during larval development o f the coral reef asteroid Acaruhaster planci (L.). J. Exp. Mar. Biol. Ecol. 65: 173-193.

M o r r is . R . H . , D . P. A b b o t t , and E. C . K a d e r u e . 1980. Intertidal invertebrates o f California. Stanford University Press, Stanford, C A .

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P a in e , R. T. 1966. Food web complexity and species diversity. Am. Nat. 100: 6 5 -7 5 .

P h i f e r . L. D .. and T . C . T h o m p s o n . 1937. Seasonal variations in the surface waters of San Juan Channel during the five year period January 1931 to December 30, 1935. J. Mar. Res. 1: 3 4 -5 9 .

R icketts, E. F ., and J. Calvin. 1968. Between Pacific tides. 4th ed.

Revised by J. W. Hedgepeth. Stanford University Press, Stanford, CA.

S a b o u R in , T. D.. and W. B. S t i c k l e . 1981. Effects o f salinity on respiration and nitrogen excretion in two species of echinoderms. Mar. Biol. 6 5 : 91 -9 9 .

SHIRLEY, T „ and W. B. S t i c k l e . 1982a. Responses of Leptasterias hexactis (Echinodermata: Aateroidca) to low salinity. I. Survival, activity, feeding, growth and absorption efficiency. Mar. Biol. 69: 147-154.

19826. Responses o f Leptasterias hexactls (Echinodermata:Asleroidca) to low salinity. II. Nitrogen metabolism, respiration and energy budget. Mar. Biol. 69; 155-163.

S n e d e c o r , C . W ., and W. G. C o c h r a n . 1980. Statistical methods. Iowa Stale University Press. Ames, JA.

S t a n c y k . S. E „ and P. L. S h a f f e r . 1977. The salinity tolerance of Ophiothrix angulata (Say) (Echinodermata: Ophiuroidea) in lati- tudinally separate populations. J. Exp. Mar. Biol. Ecol. 29:35 -4 3 .

STEEL, R. G ., and J. H . T o r r i e . 1980. Principles and procedures of statistics. McGraw-Hill Publications, New York.

S t e v e n s , M. 1970. Procedures for induction or spawning and mciolic maturation o f starfish oocytes by treatment with l-mclhyladenine. Exp. Cell Res. 59: 482-484.

S tick le , W. B. 1985. Effects of environmental factor gradients on scope for growth in several species of carnivorous marine invertebrates, In Marine biology of polar regions and effects of stress on marine organisms. Edited by J. S. Gray and M. E. Christiansen. John Wiley & Sons, New York. pp. 601-616.

S t i c k l e , W. B., and G. J. D e n o u x . 1976. Effects of in situ tidal salinity fluctuations on osmotic and ionic composition of body fluid in Southeastern Alaska rocky intertidal fauna. Mar. Biol. 37: 125-135.

S t r a t h m a n n , M. 1974. Methods in developmental biology: techniques for the study of eggs, cmbiyos, and larvae o f marine invertebrates at Friday Harbor Laboratories. Friday Harbor Laboratories, Friday Harbor, WA.

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CHAPTER 2

DOES SALINITY ACCLIMATION AFFECT THE LARVAL TOLERANCE,

PHYSIOLOGY, AND EARLY DEVELOPMENT OF STRONGYLOCENTROTUS

DROEBACHIENSIS (O .F . MULLER, 1776) , £ . PALLIDUS (G.O. SARS,

1 8 7 1 ) , AND LYTECHINUS VARIEGATUS (LAMARCK) (ECHINODERMATA:

ECHINOIDEA)?

ABSTRACT

L a r v a l t o l e r a n c e a n d d e v e l o p m e n t a l r a t e s o f

S t r o n e v l o c e n t r o t u s d r o e b a c h i e n s i s . S . p a l l i d u s . and L v te c h in u s

v a r i e g a t u s w e re d e t e r m i n e d f o r two e x p e r im e n t s : 1) D i r e c t

t r a n s f e r o f f e r t i l i z e d e g g s t o l o w e r e d s a l i n i t y ; a n d 2 )

A c c l im a t io n o f a d u l t u r c h i n s t o low ered s a l i n i t y f o r 1 -4 wk p r i o r

t o spaw ning . F e r t i l i z e d eggs o f £ . d r o e b a c h ie n s i s and £ . p a l l i d u s

w ere d i r e c t l y t r a n s f e r r e d t o 30, 25, 20, 15, 1 2 .5 , and 1 0 ° / ° ° S a t

1 0 ° C . A d u l t S . d r o e b a c h i e n s i s a n d £ . p a l l i d u s w e re a l s o

a c c l im a te d t o t h e same s a l i n i t i e s f o r 2, 3, and 4 wk p r i o r t o

s p a w n i n g . F e r t i l i z e d e g g s o f JL. v a r i e g a t u s w e re d i r e c t l y

t r a n s f e r r e d t o 35, 30, 2 7 .5 , 25 , 20 , 15, and 1 0 ° / ° ° S a t 18 and

23°C. A d u l t Ij. v a r i e g a t u s were a c c l im a te d t o t h e same s a l i n i t i e s

and t e m p e r a tu r e s f o r 1, 2 , and 4 wk p r i o r t o spaw ning . F o r t h e

a c c l i m a t i o n e x p e r im e n t s , f e r t i l i z e d eggs w ere c u l t u r e d a t t h e

same te m p e ra tu re and s a l i n i t y a s a d u l t s . Development and s u r v i v a l

t o m e ta m o rp h o s is w ere examined i n a l l c u l t u r e s . D evelopm enta l

10

11

r a t e s and p e r c e n t s u r v i v a l t o m etam orphos is v a r i e d d i r e c t l y w i th

s a l i n i t y f o r l a r v a e o f a l l s p e c i e s . An o b s e rv e d i n c r e a s e i n t h e

n u m b e r o f a b n o r m a l p l u t e i a n d a d e c r e a s e i n s u r v i v a l t o

m e t a m o r p h o s i s o c c u r r e d a t s a l i n i t i e s b e lo w 3 0 ° / o o f o r £ •

p a l l i d u s . £,. d ro eb a c h l e n s i s p l u t e i s u r v i v e d t o s e t t l e m e n t and

m etam orphos is a t s a l i n i t i e s above 1 7 .5 ° / ° ° S . Fo r i . v a r i e g a t u s .

s u r v i v a l to m etam orphos is d e c re a s e d a t s a l i n i t i e s be low 3 5 ° / ° °

(Q lO v a l u e s f o r m e t a m o r p h o s i s - 0 , 3 8 0 - 0 . 3 8 4 ) . T h e r e w e re

s i g n i f i c a n t (ANOVA) t e m p e ra tu re and s a l i n i t y e f f e c t s on m e ta b o l i c

r a t e s o f i . v a r i e g a t u s p l u t e i . I*, v a r i e g a t u s and £ . p a l l i d u s

l a r v a e a r e s t e n o h a l i n e when c o m p a re d t o t h e l a r v a e o f S..

d r o e b a c h i e n s i s . Coelomic c a v i t y l a c t i c a c i d l e v e l s o f a d u l t £ .

d r o e b a c h i e n s i s and S. p a l l i d u s a c c l im a te d t o low s a l i n i t y were

s i g n i f i c a n t l y h i g h e r t h a n c o n t r o l s a t 30°/ooS b u t t h e r e was no

h i s t o l o g i c a l e v i d e n c e o f a l t e r e d g o n ad a l t i s s u e . Gonadal NPS

v a l u e s o f S. d r o e b a c h ie n s i s and £ . p a l l i d u s were s i g n i f i c a n t l y

low er a t 1 7 .5 ° /o o S th a n a t t h e h i g h e r s a l i n i t i e s . C e l l vo lum es o f

f e r t i l i z e d eggs o f a l l s p e c i e s e x h i b i t e d o sm o tic s w e l l i n g when

e x p o s e d t o lo w e re d s a l i n i t y . The p e r c e n t volume r e g u l a t i o n o f

f e r t i l i z e d e g g s o f t h e t h r e e s p e c i e s v a r i e d i n d i r e c t l y w i th

s a l i n i t y . The a n a e r o b ic en v iro n m en t o f t h e coe lom ic f l u i d s i n

u r c h i n s a c c l i m a t e d t o low s a l i n i t y a d v e r s e l y a f f e c t e d t h e

v i a b i l i t y o f gam e tes . LC50 v a lu e s ( ° / o o S ) , d e v e lo p m e n ta l r a t e s ,

and s u r v i v a l t o m etam orphos is i n d i c a t e t h a t a c c l i m a t i o n o f a d u l t

u r c h i n s t o low er s a l i n i t y p r i o r t o spaw ning and f e r t i l i z a t i o n

does n o t enhance deve lopm en t o r s u r v i v a l o f embryos exposed t o low

12

s a l i n i t y . The s t e n o h a l i n i t y o f l a r v a l L. v a r i e g a t u s and £ .

p a l l i d u s may l i m i t a d u l t d i s t r i b u t i o n s a lo n g s a l i n i t y g r a d i e n t s .

INTRODUCTION

E c h in o d e r m s a r e c o n s id e r e d t o be s t e n o h a l i n e o rg an ism s

w i t h r e s p e c t t o t h e i r d i s t r i b u t i o n a lo n g s a l i n i t y g r a d i e n t s

p r i m a r i l y b e c a u s e th e y p o s s e s s a p e rm e ab le body w a l l (D rou in

a l . , 1985) and l a c k d i f f e r e n t i a t e d o s m o re g u la to ry and e x c r e t o r y

o rg a n s (B inyon , 1966, 1972); how ever, s e v e r a l s p e c i e s have b e e n

fo u n d t o b e more e u r y h a l in e th a n p r e v i o u s l y b e l i e v e d (B inyon ,

1 9 6 1 ; L a w r e n c e , 1 9 7 5 ; S t i c k l e and Denoux, 1976; S ta n cy k and

S c h a f f e r , 1977; T u rn e r and Meyer, 1980; a s rev ie w e d by S t i c k l e

and D ie h l , 1 9 8 7 ) . Binyon (1972) s t a t e d t h a t t h e more e u r y h a l in e

p o p u l a t i o n s o f ech inoderm s o c c u r o n ly i n r e g i o n s su ch a s th e

B a l t i c a n d B l a c k S e a s , w h e re t h e d i l u t i o n o f f u l l s t r e n g t h

s a l i n i t y h a s b e e n g r a d u a l , t a k i n g p l a c e o v e r many g e o l o g i c a l

e p o c h s , r a t h e r t h a n i n t h o s e r e g i o n s s u b j e c t t o s e a s o n a l a n d /o r

d i u r n a l f l u c t u a t i o n s o f s a l i n i t y . R e c e n t ly how ever, p o p u l a t i o n s

o f ech inoderm s have b e e n fou n d i n h a b i t a t s s u b j e c t e d t o t i d a l

a n d / o r s e a s o n a l r e d u c t i o n s o f am b ien t s a l i n i t y (Thomas, 1961;

S t i c k l e a n d Denoux, 1976; S ta n cy k and S h a f f e r , 1977; P a g e t t ,

1978; T u rn e r and Meyer, 1980; Himmelman f i l . , 1983) .

P o p u l a t i o n s o f f o u r s p e c i e s o f e c h in o d e r m s from th e

g l a c i e r i n f l u e n c e d r e g i o n o f t h e Lynn C anal i n s o u t h e a s t e r n A lask a

t o l e r a t e d f l u c t u a t i n g s a l i n i t y d u r in g th e summer months when th e

a m p l i t u d e o f t h e s a l i n i t y r an g e v a r i e d from 1 1 .4 t o 1 7 .2 ° /o o

o v e r t h e c o u r s e o f s e m id iu r n a l t i d e s ( S t i c k l e and Denoux, 1976).

I t w a s a l s o d e m o n s t r a t e d t h a t p o p u l a t i o n s o f E u o e n t a c t a

q u in q u e s e m lta and L e p a s t e r i a s h e x a c t i s from low s a l i n i t y h a b i t a t s

a r e more t o l e r a n t o f low s a l i n i t y e x p o su re th a n a r e p o p u l a t i o n s

o f t h e same s p e c i e s from n o rm a l ly h ig h s a l i n i t y w a t e r s ; how ever,

no s i g n i f i c a n t d i f f e r e n c e e x i s t s be tw een th e s a l i n i t y t o l e r a n c e s

o f p o p u l a t i o n s o f S. d r o e b a c h ie n s i s from h ig h and low s a l i n i t y

h a b i t a t s (S a b o u r in and S t i c k l e , 1981; S h i r l e y and S t i c k l e , 1982;

S t i c k l e and D ie h l , 1987) .

The d e v e lo p m e n ta l p a t t e r n s o f many m ar ine i n v e r t e b r a t e s

a r e known t o be i n f l u e n c e d by v a r i a t i o n s i n s a l i n i t y (M aclnnes

a n d C a l a b r e s e , 1 9 7 9 ; L u c a s and C ostlow , 1979; J o h n s , 1981a,

1981b, 1982; L a u g h l in , 1983; R o l l e r and S t i c k l e , 1 987 ) . S e v e ra l

s p e c i e s o f e c h in o d e r m l a r v a e h a v e a l s o b e e n show n t o b e

p a r t i c u l a r l y s e n s i t i v e t o f l u c t u a t i n g s a l i n i t y (B inyon , 1972;

P e t e r s e n and A lm eida , 1976; Greenwood and B e n n e t t , 1981; W atts g t

a l . . 1982; D rou in e£ g l . , 1985; R o l l e r and S t i c k l e , 1985)

The o b j e c t i v e s o f t h e p r e s e n t i n v e s t i g a t i o n w ere to

( 1 ) compare t h e e f f e c t s o f lo w ered s a l i n i t y on t h e d e v e lo p m en ta l

p a t t e r n s a n d s u r v i v a l t o m e t a m o r p h o s i s o f l a r v a l

S t r o n g v l o c e n t r o t u s d r o e b a c h i e n s i s ( O . F . M u l l e r , 1 7 7 6 ) ,

S t r o n p v l o c e n t r o t u s p a l l i d u s (G.O. S a r s , 1871) an d L v te c h ln u s

v a r i e g a t u s (L a m a rc k ) ; (2) i d e n t i f y any p o s s i b l e b e n e f i t s t o th e

deve lopm en t o r s u r v i v a l o f l a r v a e i n c u r r e d by a c c l i m a t i n g a d u l t

u r c h i n s t o lo w ered s a l i n i t y p r i o r t o spaw ning;

14

(3 ) d e te rm in e i f s a l i n i t y and te m p e ra tu re v a r i a t i o n s a f f e c t th e

m e ta b o l i c r a t e s o f l a r v a l 1 . v a r l e p a t u s .

15

MATERIALS Aim METHODS

DIRECT TRANSFER STOBIBS

M ature a d u l t s o f S t r o n e v lo c e n t r o t u s d r o e b a c h ie n s i s and £ .

p a l l i d u s w ere c o l l e c t e d i n t h e v i c i n i t y o f San J u a n I s l a n d , WA

(U .S .A .) d u r in g F e b ru a ry 1986. Specimens w ere c o l l e c t e d a t 70-90

m d e p th d u r in g a d re d g in g t r i p on t h e R/V Nugg e t i n San J u a n

Channel (48 °3 5 'N 123°W). A l l u r c h i n s were r e t u r n e d t o t h e F r id a y

H arbor L a b o r a t o r i e s and m a in ta in e d i n a r u n n in g s e a w a te r sy s tem .

W a te r t e m p e r a t u r e a n d s a l i n i t y o f t h e s e a w a te r sy s tem were

m e a s u r e d d a i l y a n d b o t h show ed s l i g h t v a r i a t i o n d u r in g t h e

e x p e r im e n ta l p e r i o d . W ater t e m p e ra tu re v a r i e d from 9 .0 t o 10°C (x

t S . E . - 9 .9 + 0 .2 0 °C ; n - 45) and s a l i n i t y r a n g e d from 3 0 .0 t o

3 1 ° / o o ( 3 0 . 3 ± 0 . 8 ° / o o S ; n - 4 5 ) d u r i n g t h e c o u r s e o f t h e

e x p e r im e n t . L i t t l e s e a s o n a l v a r i a t i o n o c c u rs i n t h e s a l i n i t y o f

t h e w a te r s u r r o u n d in g San J u a n I s l a n d . P h i f e r and Thompson (1937)

fo u n d mean m onth ly s a l i n i t y o f w a te r s i n t h i s a r e a t o v a r y from

2 9 .7 ° / o o i n J u l y t o 3 0 .7 ° /o o i n O c to b e r . F u r th e rm o re t h e w a te r

mass was n e a r l y homogenous i n s a l i n i t y t o a d e p th o f 100 m.

F o r t h e d i r e c t t r a n s f e r e x p e r i m e n t s , male and fem ale

S.. d r o e b a c h i e n s i s a n d £.. p a l l i d u s w ere in d u ce d t o spawn by

co e lo m ic i n j e c t i o n w i th 2 ml o f 0 .5 M KC1 (S tra th m a n n , 1 9 7 4 ) . A l l

eggs w ere washed i n f i l t e r e d ( 1 .0 urn) s e a w a te r and w ere f e r t i l i z e d

w i t h sperm from m ales o f t h e same s p e c i e s . The c r i t e r i a u s e d i n

d e te r m in in g th e s u c c e s s o f f e r t i l i z a t i o n w ere th e f o rm a t io n o f

th e f e r t i l i z a t i o n e n v e lo p e and th e f i r s t c le a v a g e o f t h e z y g o te .

Two h u n d red f e r t i l i z e d eggs from e ach s p e c i e s w ere p l a c e d i n 200

ml o f f i l t e r e d ( 1 . 0 um) s e a w a t e r a t e a c h o f t h e f o l l o w in g

s a l i n i t i e s : 30, 25, 20 , 15, 1 2 .5 , and 1 0 ° /o o ( te m p e r a tu r e was

9 .9 t 0 .20°C (x * S .E . ; n - 6 5 ) , D ev e lo p in g embryos and l a r v a e

were m a in ta in e d a t t h e s e s a l i n i t i e s th ro u g h o u t t h e e x p e r im e n ta l

p e r i o d . C u l t u r e b o w ls w e r e m a in ta in e d i n a p l e x i g l a s s w a te r

t a b l e c o n n e c te d t o t h e f lo w - th ro u g h n a t u r a l s e a w a te r sy s tem o f

t h e l a b o r a t o r i e s . The w a te r i n e ach c u l t u r e was changed d a i l y

th ro u g h o u t t h e c o u rs e o f t h e e x p e r im e n t .

M ature L v te c h in u s v a r i e p a t u s w ere c o l l e c t e d a t S t . Jo se p h

Bay, F l o r i d a , U .S .A . (2 9°53 'N ; 85°24'W) d u r in g J u l y 1985 and May

1986. A l l u r c h i n s were h e ld o v e r n i g h t i n a f lo w - th ro u g h s e a w a te r

t a n k b e f o r e b e i n g t r a n s p o r t e d t o L o u i s ia n a S t a t e U n i v e r s i t y .

A d u l t s w ere h e l d i n 38-1 a q u a r i a (10 u r c h in s /a q u a r iu m ) a t t h e

same t e m p e ra tu re and s a l i n i t y a s th e c o l l e c t i o n s i t e f o r two days

p r i o r t o spaw ning . Spawning o f a d u l t s , and f e r t i l i z a t i o n o f eggs

w e re b y t h e same m e th o d s u s e d f o r £ . d r o e b a c h ie n s i s and £ .

p a l l i d u s .

Two h u n d r e d f e r t i l i z e d 1,. v a r i e g a t u s eggs w ere p l a c e d

i n 200 ml o f f i l t e r e d ( 1 .0 um) s e a w a te r a t e i t h e r 18 o r 23°C and

a t e a ch o f th e f o l l o w in g s a l i n i t i e s : 10, 15, 20, 25, 2 7 .5 , 30 and

3 5 ° / o o . C u l t u r e b o w l s w e r e m a i n t a i n e d i n a n i n s u l a t e d ,

f lo w - th ro u g h p l e x i g l a s s w a te r t a b l e c o n n e c te d t o a t e m p e ra tu re

c o n t r o l l e d w a te r r e c i r c u l a t o r . D e v e lo p in g embryos and l a r v a e were

m a i n t a i n e d u n d e r t h e s e c o n d i t i o n s th ro u g h o u t th e e x p e r im e n ta l

p e r i o d . The w a te r i n e a ch c u l t u r e was changed d a i l y th ro u g h o u t

t h e c o u r s e o f t h e e x p e r im e n t .

C e l l v o lu m e m e a s u re m e n ts w ere made on f e r t i l i z e d eggs

o f £ . d r o e b a c h ie n s i s and £ . p a l l i d u s 4 h a f t e r t r a n s f e r t o lo w ered

s a l i n i t y , and on 1 . v a r i e g a t u s eggs 3 h a f t e r t r a n s f e r t o low

s a l i n i t y . C o n t r o l s c o n s i s t e d o f f e r t i l i z e d eggs from t h e same

s a l i n i t y t o w hich th e a d u l t s were a c c l im a te d . P e r f e c t osmometer

c a l c u l a t i o n s were made by d i v i d i n g th e h i g h e s t s a l i n i t y u s e d f o r

ea ch s p e c i e s by th e low er s a l i n i t i e s . C e l l volume r a t i o s were

a l s o c a l c u l a t e d t o y i e l d w a t e r d i l u t i o n i n f o r m a t i o n f o r

n i n h y d r i n - p o s i t i v e s u b s ta n c e c o n c e n t r a t i o n s and p e r c e n t volume

r e g u l a t i o n in f o r m a t io n . The r a t i o s were o b t a i n e d by d i v i d i n g th e

c e l l v o lu m e a t 2 5 , 2 0 , and 1 7 . 5 ° / ooS by t h e c e l l volume a t

3 0 ° / o o S f o r b o t h S. d r o e b a c h i e n s i s a n d S.. p a l l i d u s and by

d i v i d i n g th e c e l l volume a t 30, 2 7 .5 , 25, and 2 0° /ooS by th e

c e l l v o lu m e a t 3 5 ° /o o S f o r J*. v a r i e g a t u s . P e r c e n t v o lu m e

r e g u l a t i o n m e a s u r e m e n ts w e re made b y f i r s t c a l c u l a t i n g th e

d i f f e r e n c e b e tw e e n th e p e r f e c t osmometer v a l u e s an d t h e c e l l

v o lu m e r a t i o s ; The r e s u l t a n t v a lu e s were t h e n d i v i d e d by th e

d i f f e r e n c e b e t w e e n t h e p e r f e c t osmometer v a lu e an d t h e h ig h

s a l i n i t y r e f e r e n c e .

D u r i n g t h e e a r l y c l e a v a g e s t a g e s a l l c u l t u r e s w e re

e x a m in e d h o u r l y t o d e t e r m i n e d e v e l o p m e n t a l r a t e s . Once t h e

p l u t e u s s t a g e was re a c h e d , t h e c u l t u r e s w ere exam ined d a i l y . Qio

v a lu e s were c a l c u l a t e d f o r m etam orphosis o f L. v a r i e g a t u s p l u t e i

a t e a c h s a l i n i t y . A l l p l u t e i were f e d D u n a l i e l l a t e r t i o l e c t a

d a i l y . C u l t u r i n g o f a lg a e was by th e m ethod o f G u i l l i a r d (1 9 7 5 ) .

P e r c e n t s u r v i v a l t o s e t t l e m e n t and m etam orphosis was d e te rm in e d

f o r e ach c u l t u r e .

The p e r c e n t synch rony o f e a r l y c le a v a g e was d e te rm in e d f o r

t h e 1 . v a r i e g a t u s c u l t u r e s a t e a c h s a l i n i t y 4 d a y s a f t e r

f e r t i l i z a t i o n . Synchrony was d e te rm in e d by c o u n t in g t h e number o f

e m b ry o s a t t h e m o s t p r e v a l e n t d e v e lo p m e n t a l s t a g e and th e n

d i v i d i n g by th e t o t a l number o f embryos i n t h e c u l t u r e .

F ou r days a f t e r s e t t l e m e n t and m etam orphos is 1200 j u v e n i l e

L- v a r i e g a t u s e a c h f ro m t h e 30 a n d 3 5 ° / o o S a t 23°C w e re

b a c k - t r a n s f e r r e d t o 10, 15, 20, 25, 2 7 .5 , 30, and 3 5° /ooS (200

u r c h i n s / s a l i n i t y ) . P e r c e n t s u r v i v a l a f t e r f o u r days e x p o su re was

d e t e r m i n e d on d u p l i c a t e sam ples from e a c h s a l i n i t y . J u v e n i l e s

w ere f e d a m o d i f i c a t i o n o f t h e a r t i f i c i a l d i e t o f K l in g e r a l .

(1 9 8 6 ) . The d i e t c o n s i s t e d o f : a 3% a g a r m a t r ix c o n t a i n i n g 5%

d r i e d fo o d . The d r i e d food c o n s i s t e d o f : 29% sh r im p , 19% s e a

t r o u t , 33% seaw eed, 17% w heat g l u t e n , 1% l e c i t h i n , 0.5% v i t a m i n

C, and 0.5% v i t a m i n B.

ACCLIMATION STUDIES

F o r t h e a c c l i m a t i o n e x p e r i m e n t s , 12 a d u l t s o f £..

d r o e b a c h ie n s i s and £ . p a l l i d u s w ere s t e p w is e a c c l im a te d t o 25,

2 0 , 1 7 . 5 , 15 a n d 1 0 ° /o o S ( 5 ° / o o p e r day) and h e l d a t e ach

s a l i n i t y f o r 2 , 3 , and 4 wk p r i o r to spaw ning . A f t e r t h e d e s i r e d

a c c l i m a t i o n was c o m p le te d , spaw ning and f e r t i l i z a t i o n o f gam etes

w as a t t e m p t e d . Upon s u c c e s s f u l f e r t i l i z a t i o n , t h e embryos and

l a r v a e w ere r e a r e d a t t h e s a l i n i t y a t w hich t h e p a r e n t s were

a c c l im a te d .

I n a s e c o n d s e t o f e x p e r i m e n t s , a d u l t L- v a r i e p a t u s

w ere c o l l e c t e d from th e same s i t e o f f F l o r i d a i n J u l y o f 1986.

A d u l t s were t r a n s p o r t e d to t h e l a b o r a t o r y and p l a c e d i n t o 38-1

a q u a r i a (1 0 u r c h i n s / a q u a r i u m ) a t t h e same t e m p e r a t u r e an d

s a l i n i t y a s t h e c o l l e c t i o n s i t e . Each aquarium was c o n n e c te d v i a

a f l o w - t h r o u g h a p p a r a t u s t o a n a d d i t i o n a l 5 0 - 1 s e a w a t e r

r e s e r v o i r . The u r c h i n s w ere s t e p - w i s e a c c l im a te d t o t h e f o l l o w in g

s a l i n i t i e s : 10, 15, 20, 25, 2 7 .5 , 30 and 35°/°<> a t 23°C. S a l i n i t y

was a d j u s t e d 5 ° /o o p e r day and te m p e ra tu re was a d j u s t e d 2°C p e r

day u n t i l t h e d e s i r e d f i n a l v a lu e s w ere a t t a i n e d . The u r c h i n s

w e r e a l l o w e d t o a c c l i m a t e t o e a c h s a l i n i t y / t e m p e r a t u r e

c o m b in a t io n f o r 1 , 2 o r 4 weeks. A f t e r t h e d e s i r e d a c c l i m a t i o n

t im e was c o m p le te d , spaw ning and f e r t i l i z a t i o n o f gam etes was

a t t e m p te d . Upon s u c c e s s f u l f e r t i l i z a t i o n , t h e embryos and l a r v a e

were r e a r e d a t t h e te m p e ra tu re and s a l i n i t y a t w hich t h e p a r e n t s

w ere a c c l im a te d .

C e l l v o l u m e m e a s u r e m e n t s , d e v e l o p m e n t a l r a t e s , a n d

s u r v i v a l t o m etam orphosis w ere d e te rm in e d a s above f o r a l l s p e c i e s

exam ined .

N i n h y d r i n - p o s i t i v e s u b s t a n c e s (NPS) w e re m e a s u re d i n

t h e g o n a d a l t i s s u e o f 2 , 3 , a n d 4 wk a c c l im a te d fem a le fi.

d r o e b a c h ie n s i s and £ . p a l l i d u s . Gonads w ere e x c i s e d , t h e n f r o z e n

i n l i q u i d n i t r o g e n and l y o p h i l i z e d . A f t e r g r in d i n g i n a W iley

m i l l , 1 0 mg o f t i s s u e w e r e l e a c h e d i n 5 ml o f 10%

5 - s u l f o s a l i c y l i c a c i d f o r 48 h . S a m p le s were c e n t i f u g e d a t

2 0 ,0 0 0 X £ f o r 15 rain and t h e s u p e r n a t a n t was a s s a y e d f o r NPS

a c c o r d in g to Rosen (1 9 5 7 ) . L euc ine was u s e d a s t h e s t a n d a r d . NPS

v a lu e s (uM’g - ^ d ry w t) a t 30, 25, 2 0 , and 1 7 .5 ° / ° ° S w ere a l s o

d i v i d e d b y t h e c e l l volume r a t i o s t o y i e l d NPS v a l u e s e x p r e s s e d

a s uM NPS p e r u n i t o f r e l a t i v e c e l l vo lum e.

G o n a d s w e r e r e m o v e d f r o m a c c l i m a t e d a d u l t £..

d r o e b a c h i e n s i s a n d £.. n a i l i d u s . f i x e d i n f o r m o l - a c e t i c

a c i d - a l c o h o l (Humason, 1 9 72 ) , d e h y d ra te d i n a l c o h o l and embedded

i n p a r a f f i n . S e c t io n s (7 um) were s t a i n e d w i th 1% t o l u i d i n e b l u e

and exam ined w i th a compound m ic r o s c o p e .

G o e lo m ic c a v i t y l a c t i c a c i d l e v e l s o f 10 a c c l i m a t e d

a d u l t S.. d r o e b a c h ie n s i s and £ . p a l l i d u s from e a c h s a l i n i t y w ere

m easu red by th e Sigma D ia g n o s t i c s ^ P y r u v a t e / L a c t a t e a s s a y . Two

h u n d re d spawned, n o n f e r t i l i z e d eggs o f b o th s p e c i e s a t 30 , 25,

and 2 0° /ooS were i n c u b a te d f o r 6 h i n 0 .0 5 , 0 .1 0 , 0 .1 5 , 0 .2 0 and

0 .2 5 mM l a c t i c a c i d p r i o r to f e r t i l i z a t i o n . C o n t r o l s c o n s i s t e d

o f spawned eggs a t e a ch s a l i n i t y i n c u b a te d f o r t h e same d u r a t i o n

i n n a t u r a l , f i l t e r e d ( 1 .0 um) s e a w a te r . Eggs w ere r i n s e d i n

2 changes o f f i l t e r e d ( 1 .0 um) s e a w a te r and t h e n f e r t i l i z e d w i th

sperm from m ales o f t h e same s p e c i e s . P e r c e n t f e r t i l i z a t i o n was

d e te rm in e d u s in g th e c r i t e r i a above .

METABOLIC RATE STUDIES

R e s p i r a t i o n r a t e s o f 4 and 8 -arm 1 . v a r i e g a t u s p l u t e i

w e re m ea su red u n d e r c o n d i t i o n s o f a c u t e l y d e c l i n i n g PO2 I n a

c l o s e d sys tem r e s p i r o m e te r ( S t r a t h k e l v l n ^ RC 200 m i c r o r e s p i r a t i o n

c e l l e q u ip p e d w i th a 1302 oxygen e l e c t r o d e ) . S i x t y - f i v e p l u t e i , i n

200 u l o f a i r - s a t u r a t e d s e a w a te r , were a l lo w e d t o a c c l im a te to

t h e a p p a r a tu s f o r 1 h . A f t e r t h i s t im e , t h e r e s p i r o m e t e r was

s e a l e d and t h e d e c l i n e i n PO2 was fo l lo w e d on a s t r i p c h a r t

r e c o r d e r c o n n e c te d t o a S t r a t h k e l v i n ^ Model 781 Oxygen M ete r .

O xygen c o n s u m p t io n r a t e s w e re c a l c u l a t e d by c o n v e r t i n g th e

o v e r a l l d e c l i n e i n PO2 i n t o u l O2 1 g*^ 1 h r ' ^ , u s in g c o n v e r s io n

f a c t o r s from th e nomograph i n S t r i c k l a n d and P a rso n s (1 9 6 8 ) . Q^q

v a lu e s w ere c a l c u l a t e d f o r r e s p i r a t i o n r a t e s a t e a c h s a l i n i t y .

One h u n d red ! • v a r i e g a t u s p l u t e i were p l a c e d i n t o m u ff le d

(450°C f o r 4 h o u r s ) chambers c o n ta i n in g 100 u l o f f i l t e r e d (0 .2 2

um) s e a w a t e r a t t h e a p p r o p r i a t e t e m p e r a t u r e a n d s a l i n i t y .

C o n ta in e r s f i l l e d w i th s e a w a te r o n ly w ere i n c lu d e d a s c o n t r o l s .

The p l u t e i w ere a l lo w e d t o i n c u b a te i n th e s e a w a te r f o r 4 -6

h o u r s . Ammonia l e v e l s w ere d e te rm in e d on d u p l i c a t e sam ples o f

i n c u b a t i o n w a te r by th e p h e n o l - h y p o c h lo r i t e m ethod o f S o lo rz a n o

( 1 9 6 9 ) a s m o d i f i e d by G r a s s h o f f a n d J o h a n n s e n (1 9 7 2 ) w i th

ammonium s u l f a t e a s t h e s t a n d a r d . E x c r e t io n r a t e s were c a l c u l a t e d

a s : uM NH4 • g*^ ■ h r * l . Qiq v a lu e s were c a l c u l a t e d f o r e x c r e t i o n

r a t e s a t e a c h s a l i n i t y . Oxygen : n i t r o g e n r a t i o s were c a l c u l a t e d

a s : uM O2 • g*^ ■ h r* * / uM NH4 • g'*- • h r ' ^ .

STATISTICAL ANALYSIS

The G e n e r a l L i n e a r M odel p r o c e d u r e u t i l i z i n g a n a l y s i s

o f v a r i a n c e (SAS I n s t i t u t e I n c . , 1985a and 1985b) w i th S c h e f f e ' s

v a lu e s ( S t e e l and T o r r i e , 1980) a s £ p o s t e r i o r i h y p o t h e s i s t e s t

w a s u s e d i n d a t a a n a l y s i s . O ne-w ay a n a l y s i s o f v a r i a n c e

c o m p a r i s o n s be tw een s a l i n i t y t r e a t m e n t s w ere made f o r p e r c e n t

f e r t i l i z a t i o n , d e v e l o p m e n t a l r a t e s , s u r v i v a l , c e l l v o lu m e ,

m e t a b o l i c r a t e s , NPS and l a c t i c a c i d l e v e l s f o r a l l s p e c i e s .

Two-way a n a l y s i s o f v a r i a n c e com parisons be tw e en t e m p e r a tu r e and

s a l i n i t y t r e a tm e n t s were made f o r 1*. v a r i e g a t u s . A p r o b a b i l i t y

l e v e l o f 0 .0 1 was s i g n i f i c a n t f o r a l l a n a l y s e s .

Mean l e t h a l s a l i n i t i e s (28 day LC5QS) were d e te rm in e d

from m o r t a l i t y c o u n ts o f a d u l t s , a c c l im a te d em bryos, and d i r e c t

t r a n s f e r embryos u s i n g l o g i t a n a l y s i s ( S i l v e r s t o n e , 1957) when

two o r more s a l i n i t i e s c o n ta i n e d b o th l i v e and dead u r c h i n s . The

S p ea rm an-K arber method (F in n e y , 1971) was u s e d when l e s s t h a n

two s a l i n i t i e s c o n ta in e d b o th l i v e and dead u r c h i n s .

RESULTS

FERTILIZATION SUCCESS AND CELL VOLUME MEASUREMENTS

The p e r c e n t f e r t i l i z a t i o n ( x + S . E . ) f o r t h e d i r e c t

t r a n s f e r e x p e r i m e n t w a s 9 8 . 3 * 2.7% ( n - 1 0 ) f o r t h e S..

d r o e b a c h ie n s i s c u l t u r e s , 9 7 .7 + 4.3% (n -1 0 ) f o r t h e £ . p a l l i d u s

c u l t u r e s , and 9 7 .5 + 4.3% ( n -5 ) f o r t h e L. v a r i e g a t u s c u l t u r e s .

The p e r c e n t f e r t i l i z a t i o n o f gam etes o b t a i n e d from a c c l im a te d

a d u l t s s i g n i f i c a n t l y d e c r e a s e d i n t h e lo w e r s a l i n i t i e s f o r a l l

s p e c i e s (T a b le s 1 & 2 ) . A l l gam etes from 3 and 4 wk a c c l im a te d £ .

p a l l i d u s w e re n o n v i a b l e ; t h e r e f o r e , a t t e m p t s a t f e r t i l i z a t i o n

23

w e re u n s u c c e s s f u l . p a l l i d u s w e re o b s e rv e d spaw ning a f t e r

a p p ro x im a te ly 5 -8 days a c c l i m a t i o n t o 15, 1 7 .5 , and 2 0 ° /o o S . £ .

d r o e b a c h ie n s i s gam etes a c c l im a te d t o 1 7 .5 , 15 and 10o/ o°S f o r 2 ,

3 , and 4 wk w ere a l s o n o n v ia b l e . T here was a l s o no f e r t i l i z a t i o n

o f L- v a r i e g a t u s eggs a t s a l i n i t i e s be low 20° / o o f o r any o f t h e

a c c l i m a t i o n t r e a t m e n t s o r f o r t h e d i r e c t t r a n s f e r c u l t u r e s . The

co e lo m ic f l u i d o f a d u l t u r c h i n s a t t h e s e low s a l i n i t i e s was d a rk

r e d t o brown i n c o l o r , and gave o f f an o f f e n s i v e o d o r .

Mean c e l l v o lu m e m easu rem en ts (T a b le s 3 & 4 ; F ig . 1)

i n d i c a t e e x t e n s i v e o sm o t ic s w e l l i n g o f f e r t i l i z e d eggs ex p o sed t o

low s a l i n i t y . E x te n s iv e s w e l l i n g i s a l s o i n d i c a t e d by t h e o b s e rv e d

d e c r e a s e i n p e r c e n t volume r e g u l a t i o n a t t h e low er s a l i n i t i e s f o r

a l l s p e c i e s ( T a b l e 5) . C e l l v o lu m e s i g n i f i c a n t l y i n c r e a s e d

(P < 0 .01 ) w i th d e c r e a s in g s a l i n i t y f o r a l l s p e c i e s . I,, v a r i e g a t u s

c e l l s a t 15 and 10°/ooS l y s e d b e f o r e t h e f i r s t c l e a v a g e c o u ld

o c c u r . T here was s i g n i f i c a n t s w e l l i n g o f ]*. v a r i e g a t u s c e l l s a t

2 7 .5 , 25 and 2 0 ° / ° ° S ; w hereas c e l l s a t 30 and 35° /ooS d i d n o t

s w e l l s i g n i f i c a n t l y from th e c o n t r o l s (T a b le 3 ) . T h e re was no

s i g n i f i c a n t ( P < 0 . 0 1 ) t e m p e r a t u r e e f f e c t on c e l l v o lu m e .

A c c l im a t io n t o low ered s a l i n i t y d i d n o t r e d u c e c e l l s w e l l i n g i n

S.. d r o e b a c h i e n s i s eg g s ; how ever , a c c l i m a t i o n d i d p r e v e n t c e l l

l y s i s a t 10°/ooS i n S . p a l l i d u s . £ . p a l l i d u s embryos ex p o sed t o

low s a l i n i t y e x h i b i t e d more a b n o r m a l i t i e s i n a p p e a ra n c e th a n

embryos a t 3 0 ° /o o ( F ig . 2 ) .

The f e r t i l i z a t i o n membrane o f S. d r o e b a c h i e n s i s a p p a r e n t l y

r e s t r i c t s e x t e n s i v e c e l l s w e l l i n g . C e l l s o f t h i s s p e c i e s were

o b s e rv e d t o s w e l l o u t t o t h e membrane a t 10°/ooS b u t n e v e r l y s e d .

T h is o b s e r v a t i o n i s s u p p o r te d by th e p e r c e n t volume r e g u l a t i o n

v a l u e s w hich d e c re a s e down t o 2 . 8 - 5 . 8% a t 1 7 .5 ° /o o S and th e n

i n c r e a s e b a c k up t o 16 .8 -36 .9% a t 10°/ooS (T ab le 5)

DEVELOPMENTAL RATES AND SURVIVAL 10 METAMORPHOSIS

D e v e l o p m e n ta l r a t e s a n d s u r v i v a l t o m e ta m o rp h o s is o£

a l l s p e c i e s w ere s i g n i f i c a n t l y a f f e c t e d by s a l i n i t y (T a b le s 6 & 7;

F i g s . 3 - 5 ) . There was no deve lopm ent a t s a l i n i t i e s be low 2 0 ° /o o

f o r any s p e c i e s .

M etam orphosis o c c u r r e d i n c u l t u r e s o f £ . d r o e b a c h ie n s i s a t

30 , 25 , and 20°/ooS f o r b o th t h e d i r e c t t r a n s f e r and a c c l i m a t i o n

e x p e r i m e n t s . O n ly p a l l i d u s l a r v a e a t 30°/ooS s u r v i v e d t o

m e t a m o r p h o s i s ( T a b l e 6 ) . D evelopm enta l r a t e s and s u r v i v a l t o

m e t a m o r p h o s i s was n o t s i g n i f i c a n t l y a f f e c t e d (P< 0 .01) by th e

d u r a t i o n o f a c c l i m a t i o n a t e i t h e r 20 o r 2 5 ° / o o S f o r £ .

d r o e b a c h i e n s i s . As p r e v i o u s l y m en tio n ed , o n ly 2 wk a c c l im a te d £ .

p a l l i d u s e m b ry o s w e re o b t a i n e d ; t h e r e f o r e , o n l y t h e 2 wk

a c c l i m a t i o n d a t a f o r b o t h s p e c i e s a r e t a b u l a t e d (T a b le 6 ) .

T here was no s i g n i f i c a n t d i f f e r e n c e i n d e v e lo p m e n ta l r a t e s be tw een

d i r e c t t r a n s f e r c u l t u r e s a n d a c c l i m a t e d c u l t u r e s (T a b le 6 ) ;

h o w e v e r , l a r v a l s u r v i v a l t o m e t a m o r p h o s i s o f b o t h

d r o e b a c h i e n s i s and £ . p a l l i d u s was s i g n i f i c a n t l y lo w e r i n th e

t h e 2 wk a c c l im a te d c u l t u r e s t h a n i n t h e d i r e c t t r a n s f e r c u l t u r e s

( F i g s . 3 & 4 ) .

T h e r e was no s i g n i f i c a n t d i f f e r e n c e i n th e c a l c u l a t e d

28 d a y LC50 v a lu e s o f d i r e c t t r a n s f e r embryos and a c c l im a te d

embryos o f £ . p a l l i d u s : how ever, b o t h v a l u e s f o r embryos were

s i g n i f i c a n t l y h i g h e r (P< 0 .01) t h a n t h e c o r r e s p o n d in g v a l u e f o r

a d u l t s ( F ig . 4 ) , The LC50 v a lu e f o r a c c l im a te d £ . d r o e b a c h ie n s i s

e m b ry o s was s i g n i f i c a n t l y h i g h e r t h a n t h e v a lu e f o r d i r e c t

t r a n s f e r embryos i n d i c a t i n g t h a t f o r t h i s s p e c i e s e x p o s u re o f

embryos t o low s a l i n i t y f o r an e x te n d e d p e r i o d was d e t r i m e n t a l

( F ig . 3 ) . The LC50 v a lu e f o r a c c l im a te d a d u l t £ . d r o e b a c h ie n s i s

was s i g n i f i c a n t l y low er t h a n th e c o r r e s p o n d in g v a lu e s f o r b o th

embryo c u l t u r e s .

T he d ev e lo p m en t o f 1,. v a r i e g a t u s i s a f f e c t e d by b o th

t e m p e r a t u r e a n d s a l i n i t y ( T a b l e 7 ; F i g . 5 ) ; h o w e v e r , t h e

c a l c u l a t e d Q^q v a lu e s and th e S c h e f f e ' s v a lu e s i n d i c a t e t h a t

t e m p e ra tu re i s more i n f l u e n t i a l on d e v e lo p m e n ta l r a t e s t h a n th e

5 ° / o o d i f f e r e n c e i n s a l i n i t y . The Q iq v a l u e s f o r d a y s t o

m e t a m o r p h o s i s a t 30 a n d 3 5 ° / o o S w e r e 0 . 3 8 0 a n d 0 . 3 8 4

r e s p e c t i v e l y . The d e v e lo p m e n ta l r a t e s o f L . v a r i e g a t u s a t 30 and

35°/ooS a t b o t h t e m p e ra tu re s w ere v e r y syn ch ro n o u s ( F ig . 6 ) . The

s y n c h ro n y o f deve lopm en t was s i g n i f i c a n t l y d e c r e a s e d a t 2 7 .5 ° /o o S

( F ig . 6 ) . The d e v e lo p m e n ta l r a t e s v a r i e d d i r e c t l y w i th s a l i n i t y

and t e m p e ra tu re f o r a l l c u l t u r e s . T here was no deve lopm en t a t

s a l i n i t i e s l e s s t h a n 2 7 .5 ° /o o (T a b le 7) a t e i t h e r t e m p e r a t u r e . At

2 7 .5 ° /o o S , deve lopm en t c e a s e d a t t h e 4 -arm p l u t e u s s t a g e and a l l

l a r v a e d i e d w i t h i n 4 - 5 d a y s a f t e r t h i s s t a g e was re a c h e d .

S e t t l e m e n t and m etam orphosis ( F ig . 7) o f L* v a r i e g a t u s o c c u r r e d

o n ly i n p l u t e i a t 30 and 35°/ooS a t b o t h t e m p e r a tu r e s (T ab le 7 ) .

T h e r e was a s i g n i f i c a n t l y h i g h e r (ANOVA; PC0.01) s u r v i v a l t o

m etam orphos is a t 35 t h a n a t 30°/ooS a t b o t h t e m p e r a t u r e s . There

was no s i g n i f i c a n t t e m p e ra tu re e f f e c t on s u r v i v a l o f p l u t e i t o

m e ta m o rp h o s is . T here was a s i g n i f i c a n t l y h i g h e r (ANOVA; P<0 .01)

p e r c e n ta g e o f abnorm al I*, v a r i e g a t u s p l u t e i a t 3 0 ° /o o (1 2 .3 +

0.5%) th a n a t 3 5 ° / ooS ( 9 .2 + 0 .8% ). A lm ost a l l o f t h e p l u t e i a t

2 7 .5 ° /o o S (9 8 .7 + 1.5%) were v e r y abnorm al i n a p p e a ra n c e when

compared t o l a r v a e a t t h e two h i g h e r s a l i n i t i e s ( F ig . 8 ) .

The 28 day LC50 f o r a d u l t L. v a r i e g a t u s was d e te r m in e d to

be 1 8 ° / ° ° S ( F ig . 5 ) . A c c l im a t io n o f a d u l t u r c h i n s t o 1 , 2 o r 4

w e e k s a t lo w e re d s a l i n i t y d i d n o t enhance l a r v a l s u r v i v a l o r

a l t e r t h e d e v e l o p m e n t a l p a t t e r n s o f t h i s s p e c i e s from t h a t

o b s e rv e d w i th t h e d i r e c t t r a n s f e r e x p e r im e n t a t t h e same c u l t u r e

s a l i n i t y ( F ig . 5) (ANOVA; P < 0 .0 1 ) . L a r v a l d e v e lo p m e n ta l r a t e s and

s u r v i v a l d a t a w e r e s o s i m i l a r t h a t t h e y w e r e v i r t u a l l y

i n d i s t i n g u i s h a b l e from th e d i r e c t t r a n s f e r d a t a .

The j u v e n i l e L. v a r i e p a t u s w hich w ere b a c k - t r a n s f e r r e d t o

t h e v a r i o u s s a l i n i t y r e g im e s a t 23°C, e x h i b i t e d no enhanced

s u r v i v a l ( T a b l e 8 ) o v e r a d u l t u r c h i n s e x p o s e d t o t h e same

s a l i n i t i e s ( F ig . 5 ) . By one week a f t e r t r a n s f e r t h e r e w ere no

u r c h i n s a l i v e a t 15 ° /o o o r low er s a l i n i t i e s . The p e r c e n t s u r v i v a l

o f j u v e n i l e u r c h i n s a t th e h i g h e r s a l i n i t i e s h a d n o t changed

s i g n i f i c a n t l y (ANOVA; P < 0 .0 1 ) b y one w eek f ro m t h e v a lu e s

c a l c u l a t e d a t f o u r days (T a b le 8 ) .

27

HISTOLOGY, EES, M£> LACTATE ANALY SIS

H i s t o l o g i c a l e x a m i n a t i o n r e v e a l e d n o o b s e r v a b l e

d i f f e r e n c e s i n gonada l s t r u c t u r e be tw een a d u l t u r c h i n s a c c l im a te d

t o h i g h and low s a l i n i t y ( F ig . 9 ) .

T here was no s i g n i f i c a n t e f f e c t o f a c c l i m a t i o n d u r a t i o n on

n i n h y d r i n - p o s i t i v e s u b s ta n c e s o r l a c t i c a c i d l e v e l s f o r e i t h e r £ .

d r o e b a c h i e n s i s o r S. p a l l i d u s (T a b le s 9 & 10; F ig . 1 0 ) . NPS

v a lu e s o f t h e gonads from a c c l im a te d a d u l t s o f b o t h s p e c i e s w ere

s i g n i f i c a n t l y low er a t 1 7 .5 ° /o o th a n c o r r e s p o n d in g v a lu e s a t th e

h i g h e r s a l i n i t i e s (T ab le 9; F ig . 1 0 ) . T here was no s i g n i f i c a n t

d i f f e r e n c e i n gonada l NPS v a lu e s a t 25 and 30°/ooS (T a b le 9 ) .

C o e lo m ic c a v i t y l a c t i c a c i d l e v e l s v a r i e d i n d i r e c t l y

w i th s a l i n i t y f o r a d u l t £ . d r o e b a c h ie n s i s and S. p a l l i d u s (T ab le

1 0 ) . L a c t i c a c i d l e v e l s o f u r c h i n s a t 2 0 ° /° ° S w ere s i g n i f i c a n t l y

h i g h e r t h a n c o r r e s p o n d i n g l e v e l s a t 25 and 30°/ooS f o r b o th

s p e c i e s .

The e x p o su re o f u n f e r t i l i z e d eggs o f S. d r o e b a c h ie n s i s and

£ . p a l l i d u s t o i n c r e a s i n g c o n c e n t r a t i o n s o f l a c t i c a c i d r e s u l t e d

i n a s i g n i f i c a n t d e c r e a s e i n p e r c e n t f e r t i l i z a t i o n ( F ig . 1 1 ) . The

p e r c e n t f e r t i l i z a t i o n o f eggs o f £ . d r o e b a c h ie n s i s a t 20°/ooS

exposed t o 0 ,1 5 mM l a c t a t e was 66% o f th e c o n t r o l v a lu e a t t h e

same s a l i n i t y . T h is c o n c e n t r a t i o n o f l a c t i c a c i d was 0 .0 2 5 mM

below t h a t found i n th e coe lom ic f l u i d o f a d u l t u r c h i n s a f t e r 2

wk a c c l i m a t i o n (T a b le 1 0 ) . S i m i l a r l y , t h e p e r c e n t f e r t i l i z a t i o n

o f t h e eggs o f £ . p a l l i d u s a t 20°/ooS and 0 .1 5 mM l a c t a t e was 40%

o f t h e c o n t r o l v a lu e a t th e same s a l i n i t y .

METABOLIC RATES

I n t h e d e c l i n i n g oxygen t e n s i o n e x p e r im e n t , L- v a r i e g a t u s

p l u t e i e x t r a c t e d a l l d e t e c t a b l e oxygen £rom th e r e s p i r o m e t e r i n

a l l t e m p e r a tu r e - s a l i n i t y c o n d i t i o n s . There was a s i g n i f i c a n t

t e m p e r a tu r e e f f e c t on r e s p i r a t i o n r a t e s a t b o t h 30 and 35°/ooS

f o r b o t h 4 and 8 -arm p l u t e i ( F ig . 12; T ab le 1 1 ) . T em pera tu re d i d

n o t s i g n i f i c a n t l y a f f e c t t h e r e s p i r a t i o n r a t e s a t 2 7 .5 ° /o o S f o r

t h e 4 -a rm p l u t e i . R e s p i r a t i o n r a t e s w ere s i g n i f i c a n t l y d e p r e s s e d

a t 2 7 .5 ° /o o S f o r th e 4 -arm p l u t e i . R e s p i r a t i o n r a t e s w ere n o t

s i g n i f i c a n t l y d i f f e r e n t be tw een 30 and 3 5 ° /° ° S f o r t h e 4 -arm

p l u t e i ; h o w e v e r , t h e r a t e s w e re d i f f e r e n t b e t w e e n t h e two

s a l i n i t i e s f o r t h e 8 -arm p l u t e i .

Ammonia e x c r e t i o n r a t e s o f 1 - v a r i e g a t u s p l u t e i w ere

s i g n i f i c a n t l y d i f f e r e n t a t b o th te m p e ra tu re s f o r a l l s a l i n i t i e s

( F i g . 1 2 ; T a b l e 1 1 ) . The e x c r e t i o n r a t e s w ere s i g n i f i c a n t l y

h i g h e r a t 2 7 .5 th a n a t 30 o r 35°/ooS f o r b o th t e m p e r a t u r e s .

I t . v a r i e g a t u s p l u t e i a t 2 7 . 5 ° / o o S p o s s e s s e d a

s i g n i f i c a n t l y l o w e r 0 :N r a t i o t h a n l a r v a e a t t h e h i g h e r

s a l i n i t i e s f o r b o t h t e m p e r a t u r e s ( F i g . 1 2 ) . T h e r e was no

s i g n i f i c a n t d i f f e r e n c e i n 0 :N r a t i o s be tw een 30 and 35°/ooS a t

e i t h e r t e m p e ra tu re f o r 4 -arm o r 8 -arm p l u t e i ( F ig . 12) w i t h mean

v a lu e s r a n g i n g from 1 2 .5 t o 4 .7 i n d i c a t i n g a n i n c r e a s e d r e l i a n c e

on p r o t e i n c a ta b o l i s m a t 2 7 .5 ° /o o S .

DISCUSSION

The z o n e o f l e t h a l i t y (zone o f r e s i s t a n c e a d a p t a t i o n )

( V e r n b e r g a n d V e rn b e rg , 1972; P r o s s e r , 1986) f o r s a l i n i t y o f

l a r v a l L . v a r i e g a t u s . £ , d r o e b a c h ie n s i s and £ . p a l l i d u s i s w e l l

w i t h i n t h e o b s e rv e d t o l e r a n c e l i m i t s o f t h e a d u l t s a s s u g g e s t e d

by t h e p r e s e n t d a t a and by p r e v io u s s t u d i e s (Moore £ £ f l l . , 1963;

S a b o u r in and S t i c k l e , 1981; K l in g e r a l . , 1986; S t i c k l e and

D i e h l , 1 9 8 7 ) . The z o n e o f l e t h a l i t y i s t h e e x t r e m e o f an

e n v i r o n m e n ta l f a c t o r g r a d i e n t ( i . e . , s a l i n i t y ) w hich r e s u l t s i n

t h e o r g a n i s m ' s d e a t h a n d c a n b e u s e d a s a m easu re o f t h e

r e s i s t a n c e a d a p t a t i o n o f v a r i o u s p o p u l a t i o n s . The l a r v a l s t a g e s

o f a l l t h r e e s p e c i e s a r e t h e m ost s e n s i t i v e l i f e h i s t o r y s t a g e

w i t h r e s p e c t t o s a l i n i t y g r a d i e n t s , a s i s t r u e f o r many g roups o f

i n v e r t e b r a t e s i n c l u d i n g m o l lu s c s ( C a la b r e s e and D a v is , 1970;

W a t t s e t a l . . , 1 9 8 2 ; R o l l e r a n d S t i c k l e , 1985, 1 9 8 7 ) . S in c e

a c c l i m a t i o n o f s e a u r c h i n s from h ig h s a l i n i t y h a b i t a t s to low

s a l i n i t y does n o t enhance l a r v a l s u r v i v a l , o u r u n d e r s t a n d in g o f

t h e m echanisms r e s p o n s i b l e f o r p o p u l a t i o n s a d a p te d t o low and

v a r i a b l e s a l i n i t y m ust a w a i t f u r t h e r s t u d i e s on t h e s e o rg a n is m s .

A p p a r e n t ly , t h e r a t e o f t r a n s f e r o f e c h inode rm s t o r e d u c e d

s a l i n i t y h a s a m in i m a l e f f e c t on t h e i r s a l i n i t y t o l e r a n c e

( S t i c k l e and D ie h l , 1 9 8 7 ) . D i r e c t l y t r a n s f e r r e d A s t e r i a s f o r b e s i

i n d i v i d u a l s h a d t h e same s a l i n i t y t o l e r a n c e a s I n d i v i d u a l s i n

w hich t h e s a l i n i t y was g r a d u a l l y r e d u c e d (L o o s a n o f f , 1 9 45 ) . The

same 14 day LC50 o f a d u l t S . d r o e b a c h i e n s i s i s o b t a i n e d w h e th e r

i n d i v i d u a l s a r e d i r e c t l y t r a n s f e r r e d o r s t e p w is e a d a p te d t o t h e

30

f i n a l s a l i n i t y ( S a b o u r in and S t i c k l e , 1 9 8 1 ) .

R o l l e r and S t i c k l e (1985) d e m o n s t ra te d t h e r e l a t i o n s h i p

b e tw e en t h e e a r l y p e r i o d o f l a r v a l t o l e r a n c e s t o s a l i n i t y and

a d u l t d i s t r i b u t i o n a lo n g s a l i n i t y g r a d i e n t s f o r f o u r s p e c i e s o f

e c h in o d e rm s from t h e F r id a y H arbor a r e a . The p r e s e n t d a t a on

s a l i n i t y t o l e r a n c e o f l a r v a l S. d r o e b a c h ie n s i s and £ . p a l l i d u s t o

m e t a m o r p h o s i s a l s o c o r r e l a t e s w e l l w i t h t h e d i s t r i b u t i o n a l

p a t t e r n o f t h e a d u l t s t a g e s . S t r o n g v l o c e n t r o tu s d r o e b a c h ie n s i s i s

a c l r c u m p o la r s e a u r c h i n which t o l e r a t e s e n v i r o n m e n ta l s a l i n i t i e s

a s low a s 1 3 ° /o o from b o th th e low and h ig h s a l i n i t y e n v iro n m e n ts

o f J u n e a u , A la sk a and F r id a y H a rb o r , r e s p e c t i v e l y (S a b o u r in and

S t i c k l e , 1981; S t i c k l e and D ie h l , 1987) . The d e v e lo p m e n ta l r a t e s

and l a r v a l t o l e r a n c e s t o m etam orphosis i n d i c a t e t h a t w h i l e t h e

em bryonic s t a g e s o f S. d r o e b a c h ie n s i s a r e more s t e n o h a l i n e and

f a l l w e l l w i t h i n th e t o l e r a n c e l i m i t s o f t h e a d u l t s , t h e l a r v a e

a r e a b l e t o t o l e r a t e a r e l a t i v e l y w id e r a n g e o f s a l i n i t y

g r a d i e n t s w i t h o v e r 50 t o 90% s u r v i v i n g t o m e tam orphos is a t 20

and 3 0 ° / ° ° S r e s p e c t i v e l y . £ . p a l l i d u s a r e u s u a l l y r e s t r i c t e d t o

d e p th s g r e a t e r th a n 50 m i n t h e San J u a n A r c h ip e la g o ( K o z lo f f ,

1 9 7 4 ) , w here t h e am b ien t s a l i n i t y i s a lw ays g r e a t e r t h a n 3 0 ° /o o

(Thomson, 1981; C o l l i a s e£ a l . , 1974) . The l a r v a e o f t h i s s p e c i e s

a r e v e r y s t e n o h a l i n e and w i l l n o t s u r v i v e s a l i n i t i e s l e s s th a n

2 7 .5 ° /o o S ( R o l l e r and S t i c k l e , 1985) .

L v t e c h i n u s v a r i e g a t u s i s a n a b u n d a n t u r c h i n a lo n g th e

s o u t h e a s t e r n c o a s t o f t h e U n i te d S t a t e s . 1 . v a r i e g a t u s r a n g e s

from N o r th C a r o l i n a t o B r a z i l on t h e A m erican c o a s t and i s a l s o

31

f o u n d o f f Bermuda and th e Cape Verde I s l a n d s (Moore ££ f i l . ,

1 9 6 3 ) . v a r i e g a t u s i s n o rm a l ly found i n s e a w a te r r a n g in g from

one f o o t i n d e p th t o g r e a t e r t h a n 30 f e e t ( J . Lynn, p e r s o n a l

c o m m u n i c a t i o n ) . The no rm al s a l i n i t y i n t h e a r e a w here a d u l t s

w ere c o l l e c t e d v a r i e s from 25 t o 3 5 ° / ° ° . w h e re as , t h e te m p e ra tu re

n o r m a l ly v a r i e s from 17 to 30°C ( J . Lynn, p e r s o n a l com m unica tion ;

Moore e t a l . , 1963).

The p e l a g i c p e r i o d o f l a r v a l I*, v a r i e g a t u s i s t y p i c a l

o f t e m p e ra te s p e c i e s (T ho rson , 1950); how ever, t h i s s u g g e s t s t h a t

t h e d i s p e r s a l o f l a r v a e o f t h i s s p e c i e s i s p r o b a b ly n o t a s

e x t e n s i v e a s f o r l a r v a e from more n o r t h e r n l a t i t u d e s (T ho rson ,

1950; S tra th m a n n , 1978) . S p e c ie s such a s £ . d r o e b a c h i e n s i s and

S. p a l l i d u s . which p o s s e s s a lo n g p e l a g i c l a r v a l p e r i o d , would

b e more v u l n e r a b l e t o any v a r i a t i o n s i n e n v i ro n m e n ta l c o n d i t i o n s

t h a n s p e c i e s such a s L. v a r i e g a t u s . w hich spend l e s s t im e i n th e

w a te r column (T h o rso n , 1950; S t ra th m a n n , 1978) .

R e s u l t s f ro m a p r e v i o u s i n v e s t i g a t i o n s u g g e s t t h a t

s a l i n i t y t o l e r a n c e o f t h e e a r l y s t a g e s o f ech inoderm l a r v a e may be

m o d i f i e d by a c c l im a t i n g a d u l t s t o r e d u c e d s a l i n i t i e s and t h a t

t h e o v a a r e m ore s t o n g l y i n f l u e n c e d by low s a l i n i t y t h a n

s p e r m a t o z o a . G e z e l iu s (1963) found t h a t t h e c l e a v a g e r a t e o f

f e r t i l i z e d Psammechinus m i l i a r i s eggs a t a g iv e n t e m p e r a tu r e was

r e l a t e d t o t h e s a l i n i t y a t w hich t h e p a r e n t s h a d b e e n a d a p te d .

T he p r e s e n t d a t a i n d i c a t e t h a t th e a c c l i m a t i o n o f a d u l t £ .

d r o e b a c h i e n s i s . £ . p a l l i d u s . a n d 1 . v a r i e g a t u s t o l o w e r e d

s a l i n i t y does n o t enhance t h e s u b s e q u e n t deve lopm en t o r s u r v i v a l

32

o f e m b r y o n ic s t a g e s t o m e t a m o r p h o s i s . I n t h i s s tu d y l a r v a l

m o r t a l i t y was f r e q u e n t l y p ro c e e d e d by t h e a p p e a ra n c e o f abnorm al

l a r v a e i n l a t e r deve lopm en t a s shown by d e a th o f v a r i e g a t u s

a t t h e 4 -arm p l u t e u s s t a g e 10-13 days a f t e r f e r t i l i z a t i o n a t

2 7 .5 ° /o o S . D elayed m o r t a l i t y o f t h i s n a t u r e would n o t be e v id e n t

w h e n s t u d y i n g o n l y t h e c l e a v a g e r a t e o f f e r t i l i z e d e g g s

( G e z e l iu s , 1963).

S in c e ech lnode rm s p o s s e s s a p e rm e ab le body w a l l (B inyon ,

1966, 1972) and a r e o sm ocon fo rm ers , th e gonads i n t h e c o e lo m ic

c a v i t y a r e n o t p r o t e c t e d from o sm o tic ch an g es and a r e t h e r e f o r e

ex p o sed t o s a l i n i t y changes i n t h e e n v iro n m e n t . T h is c o n d i t i o n i s

u n l i k e t h a t found i n o s m o r e g u la t in g m ar in e f i s h w hich may o f f e r

o s m o t i c p r o t e c t i o n t o g a m e te s ( H o a r , 1 9 6 9 ) ; t h e r e f o r e , th e

p r e i n c u b a t i o n o f gam etes t o low ered s a l i n i t y by th e a c c l i m a t i o n

o f a d u l t u r c h i n s may o n ly o f f e r t h e a d v a n ta g e o f t im e f o r gam etes

t o b e c o m e i s o s m o t i c t o r e d u c e d s a l i n i t y . H o w ev er , v o lu m e

r e g u l a t i o n o f f e r t i l i z e d ova was m in im al a s shown by o n ly 22%

r e g u l a t i o n f o r S. d r o e b a c h i e n s i s . 2% f o r £ . p a l l i d u s . and 0% f o r

L. v a r i e g a t u s a t 2 weeks a c c l i m a t i o n t o 2 0° /ooS (T a b le 5 ) .

I n m o s t m a r i n e i n v e r t e b r a t e s , t h e i s o s m o l a r i t y o f t h e

b o d y f l u i d s w i t h s e a w a t e r i s e s t a b l i s h e d by i n o r g a n i c i o n s ;

w h e r e a s , w i t h i n c e l l s o sm o t ic b a la n c e i s m a in ta in e d p a r t l y by

I n o r g a n i c i o n s a n d s m a l l - m o l e c u l a r w e i g h t o r g a n ic compounds

(Lange, 1 9 64 ) . High i n t r a c e l l u l a r c o n c e n t r a t i o n s o f amino a c id s

have b e e n d e m o n s t ra te d i n many m ar in e i n v e r t e b r a t e s (Lange, 1964;

B a g in s k i and P i e r c e , 1978; B u r to n and Feldman, 1982; Kapper £ t

f l l - . 1985; S t i c k l e ££ a l . , 1985; S t i c k l e and D ie h l , 1 9 8 7 ) . When

an an im a l i s t r a n s f e r r e d from a h ig h s a l i n i t y t o a low er s a l i n i t y

e n v iro n m e n t , and th u s exposed t o hyposm o tic s h o c k , c e l l volume

i s i n i t i a l l y i n c r e a s e d by th e o sm o tic i n f l u x o f w a t e r . T h is

p h a se i s f o l lo w e d by a r e d u c t i o n i n i n t r a c e l l u l a r c o n c e n t r a t i o n s

o f some am ino a c i d s i n r e s p o n s e t o t h e r e d u c e d e x t e r n a l

o s m o l a r i t y ( R a n k in a n d D a v e n p o r t , 1981; D ie h l , 1 9 8 6 ) . Lange

(1 9 6 4 ) f o u n d t h a t t h e t o t a l i n t e s t i n a l n i n h y d r i n - p o s i t i v e

s u b s ta n c e s o f a d u l t £ . d r o e b a c h ie n s i s c o r r e l a t e d l i n e a r l y w i th

w i th t h e s e a w a te r s a l i n i t y . The NPS l e v e l s o f t h e o v a r i e s o f

a d u l t u r c h i n s i n t h e p r e s e n t s tu d y showed a s i g n i f i c a n t d e c r e a s e

upon 2 , 3 , and 4 wk a c c l im a t i o n t o s a l i n i t i e s be low 25* 3 0 ° /o o ,

t h u s i n d i c a t i n g t h e p o s s i b l e e x p u l s i o n o f i n t r a c e l l u l a r amino

a c i d s i n r e s p o n s e t o hyposm o tic s t r e s s . The r e l a t i o n s h i p be tw een

th e s e a w a te r s a l i n i t y and t o t a l NPS on a r e l a t i v e c e l l volume

b a s i s i s l a r g e l y p a s s i v e due t o w a te r lo g g in g a t low s a l i n i t y as

o b s e rv e d i n t h e p r e s e n t i n v e s t i g a t i o n and by Lange (1 9 6 4 ) . There

w a s , h o w e v e r , no o b v i o u s e v i d e n c e o f t i s s u e dam age f ro m

h i s t o l o g i c a l d a t a , most l i k e l y due t o more s u b t l e p h y s i o l o g i c a l

e f f e c t s .

B ookbinder and S h ic k (1986) found t h a t £ . d r o e b a c h ie n s i s

o v a r i e s have a h i g h c a p a c i t y f o r t h e p r o d u c t i o n o f l a r g e amounts

o f l a c t a t e u n d e r imposed a n o x ia ; how ever , th e y a l s o found t h a t

l a c t a t e a c c o u n t e d f o r o n l y 37% o f t h e t o t a l a n o x i c h e a t

d i s s i p a t i o n , w h ic h s u g g e s t e d t h a t o t h e r end p r o d u c t s may be

p r e s e n t . The i n c r e a s e i n coe lom ic c a v i t y l a c t i c a c i d l e v e l s o f

a d u l t u r c h i n s u p o n e x p o su re t o low s a l i n i t y o b s e rv e d i n t h e

p r e s e n t i n v e s t i g a t i o n n a y be i n d i c a t i v e o f a more e x t e n s i v e

a n a e r o b ic en v iro n m en t f o r t h e e n t i r e gonad, n o t j u s t i t s i n t e r i o r

a s a r e s u l t o f p e r f u s i o n l i m i t a t i o n s , w hich i n t u r n may be

d e t r i m e n t a l t o t h e v i a b i l i t y o f g a m e t e s . T h e s e c o n d i t i o n s

r e s u l t e d i n a r e d u c t i o n o f th e v i a b i l i t y o f £ . d ro e b a c h ie n s i s

a n d S., p a l l i d u s g a m e te s i n i n d i v i d u a l s e x p o s e d t o r e d u c e d

s a l i n i t y and p r e i n c u b a t e d i n l a c t i c a c i d s o l u t i o n s s i m i l a r t o

c o n c e n t r a t i o n s fou n d i n s e a u r c h i n s .

P re v io u s s t u d i e s have p ro v id e d a t h e o r e t i c a l fram ew ork f o r

i n v e s t i g a t i o n s o f t h e r e s p o n s e s o f m a r i n e i n v e r t e b r a t e s t o

v a r i a t i o n s i n e n v i ro n m e n ta l f a c t o r s ( F ry , 1947, 1971; P r e c h t ,

1958; K inne , 1964; P r o s s e r , 1986) . V a r i a t i o n s i n e n v i ro n m e n ta l

f a c t o r s c a n r e s u l t i n p h y s i o l o g i c a l s t r e s s f o r many o rg an ism s

(Bayne £ t a l . , 1979; tfiddows e t a l* , 1981; R o l l e r and S t i c k l e ,

1985; S t i c k l e , 1985; R o l l e r and S t i c k l e , 1987; S t i c k l e and D ie h l ,

1 9 8 7 ) . Bayne (1985) d e f i n e d s t r e s s a s "an e n v i ro n m e n ta l s t i m u lu s ,

w h ic h b y e x c e e d i n g a t h r e s h o l d v a l u e , d i s t u r b s no rm al an im a l

f u n c t i o n . "

The d e v e lo p m en ta l p e r i o d o f l a r v a e p r i o r t o m etam orphosis

t o a b e n t h i c e x i s t e n c e i s an e x t r e m e ly im p o r ta n t a t t r i b u t e o f

l a r v a l "w as tage" a s d e s c r i b e d by T horson (1 9 5 0 ) . A c co rd in g t o

T h o rson (1 9 5 0 ) , t h e m o r t a l i t y o r w a s te o f l a r v a e i s c o n t r o l l e d by

t h e i r dependance on th e p l a n k to n a s a s o u rc e o f fo o d and by th e

t i m e t h e y s p e n d i n t h e p l a n k t o n . S p e c i e s s u c h a s

d r o e b a c h i e n s i s and S . p a l l i d u s . w hich have a p r o lo n g e d p l a n k t o n i c

e x i s t a n c e 50-151 days (S tra th m a n n , 1 9 78 ) , w ould have a g r e a t e r

l a r v a l w a s ta g e t h a n a s p e c i e s su ch a s S o l r o r b l s b o r e a l i s . which

s p e n d o n l y a few h o u rs i n t h e p l a n k t o n (T ho rson , 1 9 50 ) . The

l o n g e r a l a r v a i s i n t h e w a t e r column, t h e g r e a t e r i s t h e

p o s s i b i l i t y o f e n c o u n t e r i n g p r e d a t o r s o r d e t r i m e n t a l

e n v i r o n m e n t a l c o n d i t i o n s , s u c h a s s a l i n i t y f l u c t u a t i o n s . I n

a d d i t i o n , t h e r e s u l t s from t h e p r e s e n t s tu d y i n d i c a t e t h a t low

s a l i n i t y p r o l o n g s t h e l e n g t h o f t h e p l a n k t o n i c e x i s t e n c e o f

ech inoderm l a r v a e , t h u s i n c r e a s i n g p o s s i b l e l a r v a l w a s ta g e . B ased

on t h i s o b s e r v a t i o n , a n d s i n c e L. v a r i e g a t u s h a s a s h o r t e r

p e l a g i c e x i s t a n c e , one m igh t s p e c u l a t e t h a t v a r i e g a t u s m ig h t

h a v e l e s s t o t a l l a r v a l w a s t a g e t h a n £.. d r o e b a c h i e n s i s even

though £ . d r o e b a c h ie n s i s p l u t e i a r e more e u r y h a l i n e .

O xygen : n i t r o g e n r a t i o s have b e e n u s e d a s a g e n e r a l

in d e x o f s t r e s s i n v a r i o u s m ar in e o rg an ism s (Bayne, 1985; Bayne ££

a l . . 1 9 7 9 ; t f id d o w s £ t a l . , 1981, S h i r l e y and S t i c k l e , 1982;

S t i c k l e , 1 9 8 5 ) . The l o w e r r e s p i r a t i o n r a t e s o b s e rv e d i n th e

p r e s e n t i n v e s t i g a t i o n , c o u p l e d w i t h t h e e n h a n c e d e x c r e t i o n

r a t e s , r e s u l t e d i n d e p r e s s e d 0:N r a t i o s o f 4 and 8 -arm p l u t e i a t

2 7 . 5 ° / o o S w h ic h i n t u r n i n d i c a t e s a n i n c r e a s e d r e l i a n c e on

p r o t e i n a s a m e ta b o l i c s u b s t r a t e . P h y s i o l o g i c a l s t r e s s in d u c e s

p r o t e i n c a t a b o l i s m w i t h a r e s u l t i n g d e c r e a s e i n 0:N r a t i o .

I n c r e a s e d r e l i a n c e on p r o t e i n c a ta b o l i s m i s l i k e l y due t o r e d u c e d

f e e d i n g a t 2 7 .5 ° /o o S , b e c a u s e t h e r e s p i r a t i o n r a t e i s r e d u c e d .

I t i s a c c e p te d t h a t e c to t h e r m ic m e ta b o lism i s c o m p l ic a te d

w i t h v a r i o u s t e m p e r a t u r e r a n g e s a s s o c i a t e d w i t h d i f f e r e n t

36

s y s te m ic s t a t e s o f t e n i n v o lv i n g s p e c i f i c i o n i c a r r a n g e m e n ts and

a l t e r n a t i v e e n z y m a t ic p a t t e r n s (W lese r , 1 9 7 3 ) . Many o rg an ism s

e x h i b i t a t y p i c a l t e m p e r a t u r e r e l a t i o n s h i p w i t h a Q^q

a p p ro x im a te ly 2 o v e r t h e e n t i r e b i o l o g i c a l r a n g e (V a le n , 1958;

Fuhrman and Fuhrman, 1959; Mangum and Sassam an, 1 9 69 ) . A r i s e o f

10°C i n te m p e ra tu re g e n e r a l l y r e s u l t s i n a two o r t h r e e - f o l d

i n c r e a s e i n m e t a b o l i c r a t e ( S c h m i d t - N i e l s e n , 1 9 80 ) . The Q^q

v a l u e s o b t a i n e d i n th e p r e s e n t s tu d y a r e i n d i c a t i v e o f i n c r e a s e d

m e t a b o l i c r a t e s a t h i g h e r t e m p e r a t u r e s . The Q^q v a l u e s , i n

c o n j u n c t i o n w i th t h e d e v e lo p m en ta l r a t e s , m e ta b o l i c r a t e s , and

s u r v i v a l d a t a , i n d i c a t e t h a t f o r v a r i e g a t u s . s a l i n i t y a p p e a r s

t o b e t h e m a in f a c t o r i n d e t e r m i n i n g l a r v a l s u r v i v a l , t h u s

i n f l u e n c i n g t h e d i s t r i b u t i o n o f t h e s p e c i e s . T e m p e r a t u r e ,

h o w e v e r , seem s to be t h e c o n t r o l l i n g f a c t o r o f d e v e lo p m e n ta l

r a t e s d u r in g e a r l y e m b ry o g e n e s i s .

P r e v i o u s a t t e m p t s t o c u l t u r e 1*. v a r i e g a t u s embryos a t

2 7 -2 8 ° C r e s u l t e d i n c u l t u r e s w h ic h e x h i b i t e d h ig h m o r t a l i t y

d u r i n g e a r l y e m b r y o g e n e s i s . F u r t h e r m o r e , n o n e s u r v i v e d t o

s e t t l e m e n t and m etam o rp h o s is . Our d a t a i n d i c a t e t h a t t h e b e s t

t e m p e r a tu r e r a n g e f o r c u l t u r i n g 1 . v a r i e g a t u s i n te rm s o f o p t im a l

d e v e lo p m e n ta l r a t e s and s u r v i v a l to m etam orphos is a p p e a r s t o be

23-25°C .

The p r e s e n t d a t a , i n c o n ju n c t io n w i th a p r e v i o u s s tu d y

( R o l l e r and S t i c k l e , 1985) , i n d i c a t e t h a t b o th a d u l t and l a r v a l

p a l 1 i d u s a n d i . v a r i e g a t u s a r e m ore s t e n o h a l i n e t h a n

c o r r e s p o n d in g S. d r o e b a c h ie n s i s l i f e s t a g e s ; how ever, t h e l a r v a l

s t a g e s o f a l l t h r e e s p e c i e s a r e d i s t i n c t l y more s e n s i t i v e t o low

s a l i n i t y v a r i a t i o n s t h a n a r e a d u l t s . T e m p e r a t u r e w as m ore

i m p o r t a n t i n v a r y i n g d e v e l o p m e n t a l r a t e s o f 1 . v a r i e g a t u s :

w h e r e a s , s a l i n i t y was more i n f l u e n t i a l on o v e r a l l s u r v i v a l t o

m e ta m o rp h o s is . Osm otic sh o c k , a s d e te rm in e d from t h e c e l l volume

d a t a , s u g g e s t t h a t t h e g r e a t e s t m o r t a l i t y due t o s a l i n i t y s t r e s s

o c c u r s d u r i n g e a r l y e m b r y o g e n e s i s a t s a l i n i t y e x t r e m e s , b u t

a b n o r m a l d e v e lo p m e n t o c c u r s l a t e r i n l a r v a l l i f e a t s l i g h t l y

h i g h e r s a l i n i t i e s . I n a d d i t i o n , d a t a o b t a i n e d f ro m t h e

b a c k * t r a n s f e r o f j u v e n i l e s c o r r e l a t e s w e l l w i th t h e t o l e r a n c e

l i m i t s o f a d u l t s . A p p r o x i m a t e l y 84% o f t h e b a c k - t r a n s f e r r e d

j u v e n i l e s s u r v i v e d a t 2 0 ° /o o S , w hereas none s u r v i v e d a t t h e

l o w e r s a l i n i t i e s . The LC50 d a t a i n d i c a t e t h a t 18°/ooS i s t h e

l o w e r t o l e r a n c e l i m i t f o r v a r i e g a t u s . The l a r v a l t o l e r a n c e

l i m i t s o f t h e t h r e e s p e c i e s c o r r e l a t e s w e l l w i t h t h e known

d i s t r i b u t i o n o f a d u l t s . T here was no a d v a n ta g e t o l a r v a l s u r v i v a l

i n low s a l i n i t i e s i n c u r r e d b y a c c l i m a t i n g a d u l t u r c h i n s t o

h y p o s m o t i c c o n d i t i o n s . T h e s e d a t a s u g g e s t t h a t t h e zone o f

l e t h a l i t y f o r l a r v a l u r c h i n s may p o s s i b l y l i m i t t h e d i s t r i b u t i o n

o f a d u l t s a lo n g s a l i n i t y g r a d i e n t s .

ACKNOWLEDGEMENTS

A p p r e c i a t i o n i s e x t e n d e d t o A .O .D . W i l lo w s , D i r e c t o r

o f t h e F r id a y H arbor L a b o r a t o r i e s , f o r p r o v id i n g f a c i l i t i e s f o r

t h i s r e s e a r c h . We a r e in d e b te d t o J . C a p r io , H. S i lv e rm a n , E.

W eidner, and J . F l e e g e r f o r r e v ie w in g e a r l i e r v e r s i o n s o f t h i s

m a n u s c r i p t . He t h a n k R. S t r a t h m a n n and H. Kapper f o r t h e i r

i d e a s a n d com m ents . S p e c ia l a p p r e c i a t i o n i s e x te n d e d t o T .F .

R o l l e r f o r t h e g r a p h i c s . T h is s tu d y form ed p a r t o f a d i s s e r t a t i o n

s u b m i t t e d i n p a r t i a l r e q u i r e m e n t f o r t h e Ph.D. o f R .A .R. T h is

r e s e a r c h was s u p p o r t e d by g r a n t s from Sigma Xi and t h e P e tro le u m

R e f in e r s E n v iro n m e n ta l C o u n c i l o f L o u i s ia n a (PRECOL).

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Table I. % Fertilization of Eggs from Acclimated Adult Urchins

Acclimation Species Time 25

Salinity (%o) 20 17.5 15 10

S.droebachiensis 2wk 9 0 .7 ± 5 .2 (A)* 8 2 .9 ± 2 .8 (BC) 0 0 03wk 9 2 .2 ± 3 .8 (A) 81 . 3 ± 4.2(CD) 0 0 04wk 8 5 .6 ± 4 .8 (BC) 7 6 .7 ± 5.3(D) 0 0 0

S. pallidus 2wk 71. 2 ± 3 .9 (A) 4 1 .4 ± 5.4(B) 0 0 0

3wk 0 0 0 0 0

4wk 0 0 0 0 0

* - Scheffe Values for comparisons belween salinities. Values with the same letter are not significantly different (P<0.01)

TABLE 2 .% FERTILIZATION OF EGGS FROM ACCLIMATED ADULT L. VAR I EG AT US

ACCLIMATION TIME SALINITY (%«,)35 30 27.5 25 20

1 Week 97 .9 ± 4 .6 (A )* 8 9 .3 ± 4.7(B) 5 4 .7 ± 5 .7 (C ) 10.2 ± 2 .4(D ) 1 1 .3 + 5 .6 (D )2 Weeks 95 .2 ± 4 .9 (A ) 9 0 .2 + 2.3(B) 57. 3 ± 4 .2 (C ) 11.3 ± 3.7(D ) 10.8 ± 3.8(D )3 Weeks 98 .2 ± 5 .7 (A ) 8 8 .6 ± 4.7(B) 6 1 .4 ± 3 .9(C ) 9 .8 ± 4 .4 (D ) 8 .9 ± 4.9(D )

♦Scheffe Values for comparisons between salinities.Means with the same letter are not significantly different (P<0.01).

T A B L E 3 . MEAN CELL VOLUME ( ^ x 10‘ 3 ) ( x + S E ;n « 2 0 ) OF LYTECHINUS VARIEGATUS*

acclim ationTIME

ACCLIMATION SALINITY

( 7 « ) 35

TRANSFER

30

SALINITY ( % o )

2 7 .5 25 20

1 wk 35 0 .8 2 0 + 0 .0 5 1 (D ) 0 .8 4 6 + 0 .0 3 7 (D ) 0 .9 6 6 ± 0 .033 (C ) 1 .2 5 3 ± 0 .0 5 3 (B ) 1 .371 ♦ 0.025(A )30 0 .8 0 1 + 0 .0 6 8 (D ) 0 .8 5 1 + 0 .0 3 6 (D ) 0 .9 5 1 ± 0 .021 (C ) 1 .1 9 4 ± 0 .0 4 2 (B ) 1 .3 8 3 0.043(A )

2 7 .5 0 .8 6 2 + 0 .0 3 3 (D ) 0 .8 4 2 0 .0 4 2 (D ) 0 .9 6 8 ± 0 .023 (C ) 1 .201 ± 0 .0 6 3 (B ) 1 .377 ■¥ 0.011(A )25 0 .8 6 0 + 0 .0 4 1 (D ) 0 .8 1 1 + 0 .0 6 9 (D ) 0 .9 3 3 ± 0 .013 (C ) 1 .1 8 2 ± 0 .0 2 1 (B ) 1 .363 ± 0.024(A )20 0 .8 8 6 + 0 .0 2 1 (D ) 0 .8 2 4 + 0 .0 5 7 (D ) 0 .9 5 4 ± 0 .024 (C ) 1 .2 6 3 ± 0 .0 6 4 (B ) 1 .448 + 0.035(A )

2 wk 35 0 .8 6 1 + 0 .0 3 2 (D ) 0 .8 8 0 + 0 .0 2 1 (D ) 0 .9 5 1 ± 0 .022 (C ) 1 .2 3 4 + 0 .0 7 2 (B ) 1.382 0.021(A )30 0 .8 0 1 + 0 .0 6 1 (D ) 0 .8 6 6 + 0 .0 3 4 (D ) 0 .9 2 9 ± 0 .011 (C ) 1 .2 4 8 ± 0 .0 4 3 (B ) 1 .374 + 0.024(A )

2 7 .5 0 .8 4 0 + 0 .0 4 6 (D ) 0 .8 8 0 + 0 .0 2 3 (D ) 0 .9 3 2 ± 0 .014 (C ) 1 .2 6 6 ± 0 .0 4 2 (B ) 1 .357 ♦ 0.028(A )25 0 .8 0 2 + 0 .0 7 1 (D ) 0 .8 2 3 + 0 .0 5 7 (D ) 0 .9 3 1 ± 0 .015 (C ) 1.210 ± 0 .0 6 3 (B ) 1 .3 5 8 + 0.028(A )20 0 .8 1 1 + 0 .0 6 2 (D ) 0 .8 2 0 + 0 .0 4 3 (D ) 0 .9 7 8 ± 0 .0 3 3 (C ) 1 .1 9 4 ± 0 .0 7 7 (B ) 1 .364 + 0.024(A )

4 wk 35 0 .7 9 6 + 0 .0 9 4 (D ) 0 .8 5 2 + 0 .0 4 1 (D ) 0 .9 4 3 ± 0 .042 (C ) 1 .1 9 1 ± 0 .0 6 3 (B ) 1 .374 + 0.026(A )30 0 .8 2 7 + 0 .0 7 3 (D ) 0 .8 6 4 + 0 .0 3 6 (D ) 0 .9 5 7 ± 0 .036 (C ) 1 .2 6 2 ± 0 .0 4 7 (B ) 1 .388 0.021(A )

2 7 .5 0 .7 9 9 + 0 .0 9 8 (D ) 0 .8 2 7 + 0 .0 6 3 (D ) 0 .9 6 4 ± 0 .053 (C ) 1 .2 7 3 ± 0 .0 6 1 (B ) 1 .373 0.024(A )25 0 .8 4 3 + 0 .0 4 1 (D ) 0 .8 6 6 + 0 .0 4 7 (D ) 0 .9 3 5 ± 0 .0 1 1 (C ) 1 .187 ± 0 .0 5 5 (B ) 1 .367 0 .036(A )20 0 .8 2 7 + 0 .0 5 5 (D ) 0 .8 4 5 + 0 .0 4 2 (D ) 0 .9 4 3 ± 0 .0 5 3 (C ) 1.221 ± 0 .0 4 3 (B ) 1 .394 + 0.042(A )

* - A l l c e l l s a t 15 6 10 % e S ly s e d .

TABLE 4. CELL VOLUME ((jji x 10 (x ± SE;n=10) OF S . DROEBACHIENSIS AND S . PALLIDUS ACCLIMATED TO5 SALINITIES FOR 2 , 3 , & 4 WEEKS.

ACCLIMATION ACCLIMATION TIME (WEEKS)SPECIES SALINITY(°/0 o ) 2 3 4

S. d r o e b a c h l e n s i s 30 2 .5 6 ± 0 .1 2 (D )* 2 .7 8 ± 0 .2 1 (D ) 2 .4 7 ± 0 .3 4 (D )25 2 .7 6 ± 0 .21 (D ) 2 .8 9 + 0 .2 0 (D ) 2 .5 9 ± 0 .1 5 (D )20 3 .5 6 ± 0 .3 2 (C ) 3 .4 4 + 0 .4 1 (C ) 3 .2 9 ± 0 .2 7 (C )

1 7 .5 4 . 32 ± 0 . 2 1 (B) 4 .6 4 + 0 .1 6 (B ) 4 .1 9 ± 0 .2 5 (B )10 6 .4 3 ± 0 .34 (A ) 6 .2 9 + 0 .3 6 (A ) 6 .5 8 ± 0 .2 9 (A )

S. p a l l i d u s 30 2 .5 2 ± 0 .3 6 (C ) 2 .3 9 + 0 .4 2 (C ) 2 .4 3 ± 0 .4 0 (C )25 2 .8 1 + 0 .2 9 (C ) 2 .7 7 + 0 .3 9 (C ) 2 .6 2 ± 0 .2 0 (C )20 3 .7 6 ± 0 .2 1 (B ) 3 .5 9 + 0 .1 5 (B ) 3 .7 2 ± 0 .1 7 (B )

1 7 .5 4 . 3 0 ± 0 .21 (A ) 4 .0 1 + 0 .1 8 (A ) 4 .2 8 t 0 .1 2 (A )10 — **

* S c h e f f e v a l u e s c a l c u l a t e d a c r o s s s a l i n i t i e s by week f o r e a c h s p e c i e s . Means w i t h th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t (P (O .O l ) .

x*Cells lysed

I

TABLE 5 . PERCENT VOLUME REGULATION FOR FERTILIZED EGGS OF S. DROEBACHIENSIS, S. PALLIDUS, AND L. VARIEGATUS.

SPECIESACCLIMATION

TIME 10 17.5SALINITY (° /o o )

20 25 27.5 30 35

2 wk 24.5 2 .8 22 60 ______ *S. d ro e b a c h ie n s is 3 wk 36.9 5 .8 52 80 ---------- * ----■

4 wk 16.8 2 .8 34 76 ---- *

Z wk ** 0 2 40 * rr -r-r-

S. p a l l id u s 3 wk ** 4 .5 0 20 — * ----4 wk ** 0 0 60 — — — * —

I wk ___^ — — — 0 0 34-1 77.2 *L. v a r le g a tu s 2 wk ---- 0 0 70 96.4 *

4 wk _ _ _ 0 0 22.7 49.1 *

* - R eference S a l in i ty - No Data** - No Data - C e l ls Lysed

No Data

LnN)

\

TABLE 6 . E lapsed Days to D evelopm ental S tage

S. droebachiensis S. oallidus

30%oS 25%oS 20%. S 30%oS 25°/.»S 20%<>S

STAGEDirect

Transfer2 wk

AcclimationDirect

Transfer2wk

AcdlmationDirect

Transfer2 wk

AcdlmolionDirect

Transfer2 wk

AcdimalionDirect

Transfer2 wk

AcdimalionDirect

Transfer2 wk

Acdimalion

2 Cell 0 . 1 2 0 . 17 0 . 1 2 0 . 17 0 . 1 2 0 . 2 1 0 . 10 0 .1 2 0 .1 0 0 .1 2 0 . 12 0 . 14

8-16 Cell 0 .2 7 0 . 3 3 0 . 2 9 0 . 3 3 0 . 2 9 0 . 3 3 0 . 2 5 0 .2 9 0 . 2 5 0 .3 8 0 .4 1 0 . 4 5

Hatched Blastulo 0 .7 5 0 . 86 0 .7 5 0 . 8 6 1 .0 1 . 0 0 .7 5 0 .8 2 1 .2 1 .3 1 .5 1 .5

Prism 3 3 . 5 3 .5 3 . 5 4 4 3 3 .5 4 t t t

4-A rm Pluteus 5 6 6 6 7 7 . 5 6 6 t t t t

6 -Arm Pluteus 12 12 . 5 13 1 3 .5 14 14 13 14 t t t t

8-Arm Pluteus 17 17 19 2 0 21 2 2 19 20 t t t t

Echinus Rudiment 35 3 7 4 2 4 5 4 8 5 0 4 0 4 6 t t t t

Metamorphosis 58(C)*f 59(C) 64(B) 63(B) 74(A) 79(A) 66(B) 69(B) t t t t

1" — no data,dead culture* - Scheffe Values for comparisons between salinities. Values with the same letter are not

significantly different (P < 0 .0 1 )

inu>

\

TABLE 7. DAYS TO DEVELOPMENTAL STAGE OF L . VARIEGATUS

23°C 18°C

S T A G ESALINITY(%o)

3 5 30 27.5SALIN ITY(%o)

35 30 27.5Fertilized egg 0 0 0 0 0 01st cleavage 0 .06 0.17 0.17 0 .5 4 0 .6 2 0 .9 88-16 Cell 0 .18 0.42 0.79 1 1 1.5Hatched blastula 0.17-1.0 2 - 3 4 - 6 1.5-2 2 - 2 .5 2 - 2 . 5Late gastrula 1 .5 -2 .0 3 - 4 6 - 7 2 - 3 5 - 6 6 - 74-Arm Pluteus* 4 - 5 5 - 6 10-11 7 - 8 11-12 1 2 -1 34-Arm Pluteus** 5 - 6 6 - 8 - t 9-11 13-15 - t6-Arm Pluteus 8 -1 2 13-17 — 1 4-15 17-18 —8-Arm Pluteus 1 5 -1 7 2 0 - 2 3 — 2 1 - 2 5 2 2 -2 5 —Echinus rudimenKw/primary

podia)20-21 2 5 -2 6 — 2 9 -3 1 3 3 -3 5 —

Metamorphosis 2 4 -2 5(A) 27-31(A)

— 3 7 - 4 2(B)

4 5 -4 9 { B)

—

* Total Length = 2 5 0 /x m ** Total Length = 500yxm 1* No d a ta - D ead Culture

( )V a lu e s with th e sa m e le tte r are not sign ifican tly different ( P < 0 .0 1 )

TABLE 8 . % SURVIVAL OF JUVENILE L. VARIEGATUS 4 DAYS AFTER BACK-TRANSFERTO LOWER SALINITIES1-

ORIGINAL CULTURE SALINITY (% .) 35

TRANSFER SALINITIES (%•) 3 0 2 7 .5 25 20 15 10

30 96.1 ± 2 .7 (A ) 9 5 .2 ± 1 .3(A )* 9 6 .8 ± 3 .2 (A) 9 0 .6 ± 4 .3(B ) 8 4 .7 + 1.1 (C) 1.5 ± 0 .3 (D ) 0

35 95 .6 ± 1 .4 (A )* 9 5 .9 ± 4 .3(A ) 9 4 .8 ± 4 .2 (A) 8 9 .9 ± 3.3(B ) 8 3 .8 ± 1.2(C) 2.7 ± 0 .7 (D ) 0

t X ± S E f N*200Urchins/Treatment * Controls

( ) Scheffe values - Means with the some letter are not significantly different (P<0.01)

mLn

I

TABLE 9 - NPS (/*M-g“1 Dry w t) VALUES FOR OVARIES OF S^ DROEBACHIENSIS AND £L PALLIDUS AFTER 2 , 3 , & 4 WEEKS ACCLIMATION TO 1 7 .5 , 2 0 , 2 5 , & 30 % o S*

SPECIESACCLIMATION

SALINITYACCLIMATION TIME (WEEK)

3

S. d r o e b a c h i e n s i s

S. p a l l i d u s

30 2 6 3 .8 + 1 4 .8 (A ) 2 7 4 .6 + 2 6 . 7 (AB) 2 9 9 .5 + 4 0 .2 ( A )25 2 4 2 .3 + 2 1 .6 (A ) 3 1 7 .7 + 2 9 .3 ( A ) 3 2 5 .1 + 3 2 .3 ( A )20 2 1 7 .8 + 1 4 .7 (B ) 2 6 9 .4 + 1 0 .4 ( B ) 2 6 1 .0 + 1 1 .2 ( B )

1 7 .5 2 0 6 .3 + 1 0 .8 (B ) 2 2 8 .6 + 1 4 .3 ( C ) 2 1 4 .3 + 2 1 .1 ( C )

30 4 8 7 .6 + 2 1 .6 (A ) 5 1 7 .4 + 4 5 .8 ( A ) 5 2 6 .3 + 2 5 .2 ( B )25 4 2 1 .7 + 2 0 .3 (B ) 5 6 9 .8 + 3 5 .7 ( A ) 5 6 3 .4 + 4 8 . 3(AB)20 4 3 2 .8 + 1 4 .8 (B ) 5 9 4 .3 + 4 8 .7 ( A ) 5 8 6 .2 + 1 9 .5 (A )

1 7 .5 4 1 4 .3 + 1 1 .7 (B ) 4 4 8 .6 + 2 1 .8 ( C ) 3 4 7 .3 + 4 2 .4 ( C )

* S c h e f f e v a l u e s c a l c u l a t e d a c r o s s s a l i n i t i e s by w eek f o r e a c h s p e c i e s . M eans w i t h t h e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t ( P < 0 .0 1 ) .

TABLE 10-COELOMIC LACTATE LEVELS (mM/Jt) (x ± SE;n=10) OF ADULT DROEBACHIENSIS AND S^ PALLIDUS ACCLIMATED TO 30, 25, & 20°/BO S FOR 2 ,3 , & 4 WEEKS.

SPECIESACCLIMATION

TIME 30SALINITY ( 7 oo )

25 20

S. d r o e b a c h ie n s i s 2 wk 0.0801 ± 0 .0074(H )* 0.0903 + 0.0088(FGH) 0.1392 ± 0.0088(D)

3 wk 0.0906 ± 0.0092(FGH) 0.0942 + 0.0073(FGH) 0.1694 ± 0.0083(C)

4 wk 0.0823 ± 0.0098(GH) 0.1004 + 0 .0090(F ) 0 .1866 ± 0.0078(B)

S. p a l l i d u s 2 wk 0.0834 ± 0.0079(GH) 0.0994 0.0082(FG) 0.1772 ± 0.0074(BC)

3 wk 0.0797 ± 0.0088(H) 0 .1192 ± 0.0073(E) 0 .2073 i 0.0087(A)

4 wk 0.0861 ± 0.0062(GH) 0.1255 ± 0.0096(DE) 0.1991 ± 0.0098(AB)

* Scheffe v a lu e s c a l c u l a t e d f o r each s a l i n i t y . Means w i th th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t .

TABLE 11. Q 10VALUES FOR METAMORPHOSIS TIMES, RESPIRATION RATES,

AMMONIA EXCRETION RATES FOR L. VARIEGATUS PLUTEI

4 - A R M PL U T E I 8 - A R M PLUTEI

SALINITY (%o) SALINITY(%o)27.5 30 35 30 35

R esp ira tio n R ates 1.46 2 .0 7 2.32 2 .2 5 2 . 9 0E xcretion R a tes 2 .85 2 .2 5 2 .9 0 2 .5 4 1 .94

l_n00

!

59

F ig u re 1 . C e l l volume m easurem ents f o r eggs o f £ . d r o e b a c h ie n s i s

and S. p a l l i d u s U h o u r s a f t e r f e r t i l i z a t i o n . Means w i th

th e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t (P< 0 .01 ;

n - 30 eggs p e r t r e a t m e n t ) .

MEAN

CE

LL

VOLU

ME

(fit

x 10

'*)

7.0 -6.0 -5.0-6.0-3.0- tja-1.0-

7.0-6.0-

5.0-4 .0 -3 .0 -2 .0-1

1.0 -

Ic1 l

2LLControl

S. droeboeNensb

30 27.9

I

D‘

i 1

S. pollidus

[E

+ No Data -Cell* Lysed

oe

20 15 12J5 10 Control 30 27.9 29SALINITY (% o)

22J5 20 15 12.9 10

2 wkACCLIMATION(GONTROL~20%<$)

DIRECTTRANSFER

(C0NTR0L-30%»S)

O'o

i

61

F i g u r e 2 . N orm al b l a s t u l a ( a ) and abnorm al embryo (b ) o f £ .

p a l l i d u s i l l u s t r a t i n g s a l i n i t y e f f e c t s on dev e lo p m en t.

The norm al embryo was c u l t u r e d a t 3 0 ° /o o S . The abnorm al

e m b r y o w a s o b t a i n e d f r o m a d u l t s w h ic h h a d b e e n

a c c l im a te d t o 2 0 ° / ° ° S f o r 2 wk.

63

F ig u r e 3 . Twenty e i g h t day LC50 v a lu e s ( ° /o o ) f o r d i r e c t t r a n s f e r

em bryos, a c c l im a te d embryos and a c c l im a te d a d u l t s o f £ .

d r o e b a c h i e n s l s . 95% c o n f id e n c e i n t e r v a l s were s m a l l e r

t h a n symbols u s e d . Means w i th t h e same l e t t e r a r e n o t

s i g n i f i c a n t l y d i f f e r e n t (P C 0 .01 ) .

T

35

S. droebachiensis30

25

(B)c oo 20

ot o (C)o

AdultsDirect Transfer Embryos

Acclimated Embryos

25 3010 15 20DAY OF EXPOSURE

65

F ig u re 4 . Twenty e i g h t day LC50 v a lu e s ( ° /o o ) f o r d i r e c t t r a n s f e r

em bryos, a c c l im a te d embryos and a c c l im a te d a d u l t s o f £ .

p a l l i d u s . 95% c o n f id e n c e i n t e r v a l s w ere s m a l l e r th a n

s y m b o ls u s e d . Means w i t h t h e sam e l e t t e r a r e n o t

s i g n i f i c a n t l y d i f f e r e n t (P < 0 .0 1 ) .

I

35

S. Pallidus30

(A)

25

(B)c o

o> e

20

oi n

O

AdultsDirect Transfer Embryos

Acclimated Embryos

3010 15 20DAY OF EXPOSURE

25

&

67

F ig u r e 5 . Twenty e i g h t day LC50 v a l u e s ( ° / ° ° ) f ° r d i r e c t t r a n s f e r

em bryos, a c c l im a te d embryos and a c c l im a te d a d u l t s o f

v a r i e e a t u s . 95% c o n f id e n c e i n t e r v a l s were s m a l l e r th a n

s y m b o ls u s e d . M eans w i t h t h e same l e t t e r a r e n o t

s i g n i f i c a n t l y d i f f e r e n t (P < 0 .0 1 ) .

LC

5o(%

°) S

68

B B S S B B B B S BBB-fl(A)3 0

2 5

20

A dultsD irect T ran sfe r E m b ry o s

A cc lim a ted E m b ry o s

10 15 2 0

DAY OF EXPOSURE

2 5 3 0

69

F ig u r e 6 . P e r c e n t synchrony o f deve lopm ent o f L- v a r i e g a t u s eggs

d u r in g e a r l y c le a v a g e a s a f u n c t i o n o f t e m p e ra tu re and

s a l i n i t y . M e an s w i t h t h e s a m e l e t t e r a r e n o t

s i g n i f i c a n t l y d i f f e r e n t (P cO .O l) .

1

r o

cn

CO>

■50 so

OJO

OJCJ1

rorJCJl

\ \V > \ \ \ \ \ \ \ \ \m \

OJOJOs

OJcn

% Synchrony of Development

roo

T

(T>OT"

W W w v

WW'wV

oo o o o "I rro

OJo

O

00o

O

71

F ig u re 7. L ig h t m ic ro g ra p h i l l u s t r a t i n g : (a ) 8 -arm L. v a r i e e a t u s

p l u t e i (w /p r im a ry p o d ia ) one ho u r p r i o r to s e t t l e m e n t

a n d m e t a m o r p h o s i s ; ( b ) y o u n g j u v e n i l e u r c h i n

a p p r o x i m a t e l y 45 m i n u t e s a f t e r s e t t l e m e n t a n d

m e ta m o rp h o s is .

72

a

b

73

F ig u re 8 . ( a ) Normal 8 -arm p l u t e u s (15 days o ld ) c u l t u r e d a t 23°C

and 3 5 ° /o o S ; (b) abnorm al p l u t e u s c u l t u r e d a t 23°C and

2 7 .5 ° /o o S and e x h i b i t i n g r e d u c e d l a r v a l arms and v i s c e r a l

m ass . The abnorm al p l u t e i d i d n o t f e e d .

75

F ig u re 9 . L ig h t m ic ro g ra p h s o f 7 um s e c t i o n s o f o v a r i e s o f £ .

d r o e b a c h l e n s i s an d p a l l l d u s . ( a ) o v a r i e s o f £ .

d r o e b a c h ie n s i s a c c l im a te d t o 30°/ooS f o r 4 w eeks; (b)

o v a r i e s o f S. d r o e b a c h ie n s i s a c c l im a te d t o 20° /ooS f o r

4 weeks; (c ) o v a r i e s o f £ . p a l l l d u s a c c l im a te d t o 30°/ooS

f o r 4 weeks; (d) o v a r i e s o f S. p a l l l d u s a c c l im a te d to

20°/ooS f o r 4 weeks. M a g n i f i c a t i o n - 120x.

77

F ig u r e 10. T o ta l n i n h y d r i n - p o s i t i v e s u b s ta n c e s (NPS) i n o v a r i e s

o f a d u l t S. d r o e b a c h ie n s i s and S . o a l l i d u s a c c l im a te d

t o 30, 25, 2 0 , and 1 7 , 5 ° / 0°S f o r 1 , 2, 3 , and 4 w eeks.

D a ta a r e e x p re s s e d a s uM N P S /u n i t o f r e l a t i v e c e l l volume

i n f e r t i l i z e d e g g s .

78

350S- droebachiesis

300

^ 250

200

O 1 5 0

LjJ > 100.

S. pallidusLl) 500

b 450

400

350

300

250 a 2 Weeks Acclimation 0 3 Weeks Acclimation ■4 Weeks Acclimation200

17.5 20 25 30S A L IN IT Y (%o)

79

F i g u r e 1 1 . P e r c e n t f e r t i l i z a t i o n o f eggs o f d r o e b a c h ie n s i s

a n d g.. n a l l i d u s a f t e r 6 h o u r s e x p o s u r e t o v a r i o u s

c o n c e n t r a t i o n s o f l a c t i c a c i d p r i o r t o f e r t i l i z a t i o n

( n - 2 0 0 ) . Means w i th t h e same l e t t e r a r e n o t s i g n i f i c a n t l y

d i f f e r e n t (P < 0 .0 1 ) .

80

S. droebachiensis

0.05 0.10 0.15 0 .20 0.25 Control

S. pallidus

8030

_J 60

40Ll_

20

0.25 Control0.10 0.15 0.200.05

LACTIC ACID CONCENTRATION mM

81

F ig u re 12. M e ta b o l ic r a t e s o f 4 and 8 -arm I,, v a r i e q a t u s p l u t e i

a s a f u n c t i o n o f t e m p e ra tu re and s a l i n i t y . Means w i th

t h e same l e t t e r a r e n o t s i g n i f i c a n t l y d i f f e r e n t be tw een

s a l i n i t i e s (P < 0 .0 1 ) . L e t t e r s i n d i c a t e d by a s i n g l e q u o te

( ' ) a r e s i g n i f i c a n t l y d i f f e r e n t from l e t t e r s w i t h o u t a

q u o te be tw een t e m p e r a tu r e s (P<0 . 0 1 ) .

SA

LINITY

(%

<>)

EXCRETION RATE 0 : N RATIO {jjlU NH3 * g ^ - h r -1) V O a ^ - g ^ - h r " * )

ro oj a cn cncn o O o o O o o Oro

- >cn

o jo CD roro ro roro

rororo roojro

ojcn roro

o j ooo °

o o oo

ooK>

I

4-AR

M

PLUTEI

8-ARM

PLU

TEI

SUMMARY

P o p u l a t i o n s o f s e v e r a l e c h in o d e r m s p e c i e s a r e fo u n d

i n b o th b r a c k i s h w a te r ( 0 .5 -3 0 ° /o o S ) and h y p e r s a l i n e (4 0 -8 0 ° /o o S )

e n v iro n m e n ts (K inne, 1964; S t i c k l e and D ie h l , 1 9 87 ) . The r e s u l t s

o f t h e p r e s e n t s t u d y i l l u s t r a t e t h a t n o t o n l y a r e a d u l t

e c h i n o d e r m s a b l e t o t o l e r a t e f l u c t u a t i o n s i n s a l i n i t y ; b u t

t h a t t h e l a r v a l s t a g e s a r e a l s o c a p a b l e o f s u r v i v i n g some

e x p o s u r e t o h y p o s a l i n e e n v iro n m e n ts . The s a l i n i t y l i m i t s t h a t

m a r i n e i n v e r t e b r a t e l a r v a e a r e a b le t o t o l e r a t e w i l l i n t u r n

p l a y a r o l e i n l i m i t i n g th e d i s t r i b u t i o n o f t h e s p e c i e s a lo n g

s a l i n i t y g r a d i e n t s ; t h e r e f o r e , i t i s n o t s u r p r i s i n g t h a t th e

zone o f l e t h a l i t y o f t h e l a r v a e o f a l l s p e c i e s exam ined f a l l

w e l l w i t h i n t h e o b s e rv e d t o l e r a n c e l i m i t s o f t h e a d u l t s a lo n g


The d u r a t i o n o f l a r v a l deve lopm ent w i l l i n t u r n d e te rm in e

t h e am o u n t o f t im e th e l a r v a e s t a y i n t h e w a te r column and

t h e r e f o r e how l o n g t h e y a r e e x p o s e d t o a n y v a r i a t i o n s i n

e n v i r o n m e n t a l f a c t o r g r a d i e n t s ; i n o t h e r w ords , t h e l o n g e r a

l a r v a re m a in s i n t h e p l a n k to n , t h e p o t e n t i a l f o r h i g h l a r v a l

w a s tag e (T h o rso n , 1950) i n c r e a s e s . The l a r v a e o f £ . o c h r a c e u s . £ .

d r o e b a c h i e n s i s . £J. p a l l l d u s . and S. p u r p u r a t u s a r e a l l fo u n d i n

c o l d w a t e r s ( 9 . 0 - 1 0 ° C ) , h a v e a p l a n k t o n i c e x i s t a n c e be tw een

51-151 d a y s , and a r e p o t e n t i a l l y d i s p e r s e d o v e r a w ide g e o g ra p h ic

r a n g e ( S t r a t h m a n n , 1 9 7 8 ) . L a r v a e o f t h e s e s p e c i e s c o u l d

p o t e n t i a l l y have a g r e a t e r r i s k o f b e in g exposed t o f l u c t u a t i n g

83

84

e n v iro n m e n ta l c o n d i t i o n s th a n t h e l a r v a e o f a s p e c i e s w i t h a much

s h o r t e r p l a n k t o n i c e x i s t a n c e such a s 1*. v a r l e e a t u s .

T h e r e s u l t s o f t h i s r e s e a r c h c a n b e s u m m a r iz e d a s

f o l l l o w s : ( 1 ) S a l i n i t y d o e s i n d e e d a f f e c t t h e d e v e lo p m e n ta l

r a t e s , m e t a b o l i c r a t e s , l a r v a l t o l e r a n c e s , and m orphology o f

e m b ry o n ic e c h in o d e rm s . For t h e s p e c i e s o b s e rv e d , d e v e lo p m e n ta l

r a t e s and s u r v i v a l t o m etam orphosis d e c r e a s e d upon e x p o s u re to

low s a l i n i t y ; ( 2 ) R e s p i r a t i o n r a t e s o f L . v a r l e g a t u s v a r i e d

d i r e c t l y w i th b o th te m p e ra tu re and s a l i n i t y ; w h e re a s , e x c r e t i o n

r a t e s v a r i e d i n d i r e c t l y w i th s a l i n i t y b u t v a r i e d d i r e c t l y w i th

t e m p e r a t u r e . ( 3 ) D e p r e s s e d 0 :N r a t i o s a t 2 7 . 5 ° / o o S f o r

v a r l e g a t u s i n d i c a t e p h y s i o l o g i c a l s t r e s s a t low s a l i n i t y ; (4)

l a r v a l zones o f l e t h a l i t y f e l l w e l l w i t h i n t h e o b s e rv e d t o l e r a n c e

l i m i t s o f t h e a d u l t s ; (5) Gonadal NFS v a lu e s w ere s i g n i f i c a n t l y

low er a t 2 7 . 5 ° / ooS : w h e re as , c oe lom ic c a v i t y l a c t i c a c i d l e v e l s

w ere s i g n i f i c a n t l y h i g h e r a t 2 0 ° /o o f o r S. d r o e b a c h i e n s i s and

p a l l l d u s : ( 6 ) H i s t o l o g i c a l e x a m in a t io n r e v e a l e d no o b s e r v a b le

d i f f e r e n c e s i n gonad s t r u c t u r e be tw een a d u l t u r c h i n s a c c l im a te d

t o h i g h a n d low s a l i n i t y ; (7 ) T h e r e f o r e , p r e - a c c l i m a t i o n o f

a d u l t s t o lo w e re d s a l i n i t y does n o t enhance l a r v a l t o l e r a n c e s o r

o f f e r t h e e m b r y o s a n y a p p a r e n t a d v a n t a g e i n h y p o s m o t l c

e n v iro n m e n ts ; ( 8 ) O bserved l a r v a l s a l i n i t y t o l e r a n c e s c o r r e l a t e

w e l l w i th known a d u l t d i s t r i b u t i o n s a lo n g s a l i n i t y g r a d i e n t s ; (9 )

N ew ly s e t t l e d j u v e n i l e s p o s s e s s no a p p a r e n t a d v a n ta g e i n low

s a l i n i t y w a te r s when compared t o a d u l t s o r p l u t e i . (10 ) L a r v a l

s a l i n i t y t o l e r a n c e s may i n f a c t l i m i t t h e a d u l t d i s t r i b u t i o n o f

e c h l n o d e r m s a l o n g s a l i n i t y g r a d i e n t s . Few i n v e s t i g a t o r s have

s t u d i e d th e e f f e c t o f l a r v a l t o l e r a n c e on t h e d i s t r i b u t i o n o f

a d u l t ech lnoderm s a lo n g s a l i n i t y g r a d i e n t s . The r e s u l t s o f t h e

p r e s e n t i n v e s t i g a t i o n s u g g e s t t h a t l a r v a e a r e more i n t o l e r a n t o f

low s a l i n i t y t h a n a r e a d u l t s . Most ech inoderm b i o l o g i s t s s u g g e s t

t h a t p h y s i o l o g i c a l c o n s t r a i n t s o f a d u l t s p r o h i b i t e n t r y i n t o

b r a c k i s h w a te r ; t h e r e f o r e , f u r t h e r i n v e s t i g a t i o n s s h o u ld fo c u s on

t h e p h y s i o l o g i c a l c a p a b i l i t i e s o f l a r v a e w i th r e s p e c t t o s a l i n i t y

t o l e r a n c e s a f f e c t i n g p o p u l a t i o n d i s t r i b u t i o n .

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a n d s u r v i v a l t o h a t c h i n g o f T h a i s h a e m a s to m a (G r a y )

( P r o s o b r a n c h i a : M u r ic id a e ) u n d e r l a b o r a t o r y c o n d i t i o n s . J .

Exp. Mar. B i o l . E co l . ( S u b m i t te d ) .

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e c h ln o d e rm s . M arine B io lo g y 6 5 :9 1 -9 9 .

S h i r l e y , T. , and W.B. S t i c k l e . 1982. R esponses o f L e p t a s t e r i a s

h e x a c t i s ( E c h l n o d e r m a t a : A s t e r o i d e a ) t o low s a l i n i t y . I .

S u r v i v a l , a c t i v i t y , f e e d i n g , g row th and a b s o r p t i o n e f f i c i e n c y .

M arine B io lo g y 6 9 :1 4 7 -1 5 4 .

S t i c k l e , W .B ., and G .J . Denoux. 1976. E f f e c t s o f i a s i t u t i d a l

s a l i n i t y f l u c t u a t i o n s on o sm o tic and i o n i c c o m p o s i t io n o f

b o d y f l u i d i n S o u th e a s t e r n A la sk a ro c k y i n t e r t i d a l f a u n a .

M arine B io lo g y 3 7 :1 2 5 -1 3 5 .

S t i c k l e , W.B. a n d W .J . D i e h l . 1 9 8 7 . E f f e c t s o f s a l i n i t y on

e c h i n o d e r m s . E c h in o d e rm S t u d i e s I I . M. Ja ngoux and J .M .

Law rence, e d s . A.A. Balkema, R o t te rd a m , ( i n p r e s s ) .

S tra th m a n n , R. 1978. L eng th o f p e l a g i c p e r i o d i n ech lnode rm s w i th

f e e d in g l a r v a e from t h e N o r th e a s t P a c i f i c , J . Ex p . War. B i o l .

E c o l . 3 4 :2 3 -2 7 .

T hom as, L . P . 1961 . D i s t r i b u t i o n and s a l i n i t y t o l e r a n c e i n t h e

a m p h iu r id b r i t t l e s t a r Qphlophragmus f l l o g r a n e u s (Lyman, 1875) .

B u l l , mar. S c i . G u lf . C a r ib b . 1 1 :1 5 8 -1 6 0 .

T ho rson , G. 1946. R e p ro d u c t io n and l a r v a l deve lopm en t o f t h e D anish

m ar ine b o t to m i n v e r t e b r a t e s , w i t h s p e c i a l r e f e r e n c e t o th e

p l a n k t o n i c l a r v a e o f th e Sound (O re s u n d ) . Medd. Komm. Dan.

F i s k . H a v u n d e rs . S e r . P la n k to n 4 :1 -5 2 3 .

T ho rson , G. 1950. R e p ro d u c t iv e and l a r v a l e c o lo g y o f m ar in e b o ttom

i n v e r t e b r a t e s . B io l . B u l l . 2 -4 5 .

W a t t s , S .A . , R .E . S c h e ib l in g , A.G. M arsh, and J .B . M cC lin tock .

1 9 8 2 . E f f e c t s o f t e m p e r a t u r e a n d s a l i n i t y on l a r v a l

d eve lopm en t o f s i b l i n g s p e c i e s o f E c h i n a s t e r ( E c h in o d e rm a ta :

A s t e r o i d e a ) and t h e i r h y b r i d s . B i o l o g i c a l B u l l e t i n 163 :3 4 8 -3 5 4 .

89

ISSN 0008-4301 CJZOAG 65(1) 1-218 (1987)

Canadian Journal of ZoologyPublished byTHE NATIONAL. RESEARCH COUNCIL OF CANADA

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RICHARD A. ROLLER CURRICULUM VITAE

JULY, 1987

Persona lBom: June 29,1956, E ta in A ir Force Base Phone:O ffice-(504)388-1132

(USAF), E ta in , France Home-(504)355-6767MarriedS o c ia l S e c u r i ty Number: 431-11-2144Home Address: 4551 Shelly S t , Baton Rouge, LA 70805

EducationU n iv e rs i ty o f Arkansas a t L i t t l e Rock B.S. cum laude 1980 BiologyU n iv e rs i ty o f Washington- Friday Harbor Labs- In v e r t . Embryology Course, 1981 Louis iana S ta te U n iv e rs i ty - Baton Rouge M.S. 1983 Zoology/Physiology

T hesis TopicE f fe c ts o f tem pera ture and s a l i n i t y on the rep roduction and embryological development o f the sou the rn oys te r d r i l l Thais haemastoma (Prosobranchia: M uric idae)(A dvisor- Dr. William B. S t ic k le )

U n iv e rs i ty o f Washington- Friday Harbor Labs- Larval Ecology Course, 1984 Louis iana S ta te U n iv e rs i ty - Baton Rouge Ph.D. (A n tic ipa ted 1987)

Zoology/PhysiologyD is s e r t a t i o n TopicS a l in i ty e f f e c t s on the l a r v a l to le ran c e and development o f f iv e spec ies o f echinoderms (Advisor- Dr. William B. S t ic k le )

P ro fe s s io n a l ExperienceTeaching A s s i s t a n t , U n iv e rs i ty of Arkansas a t L i t t l e Rock, Biology

Department, 1977-1980. Courses: I n v e r te b ra te Zoology, General Zoology, General Biology, V er teb ra te Embryology, V e r te b ra te Histology, Entomology

Research A s s i s t a n t , U n iv e rs i ty of Arkansas a t L i t t l e Rock, BiologyDepartment, Summer 1980

Research A s s i s t a n t , E lec tron Microscopy F a c i l i t y , U n ive rs i ty o f Arkansas a tL i t t l e Rock, 1979-1980

Teaching A s s i s t a n t , Lou is iana S ta te U n iv e rs i ty , Department ofZoology/Physiology, 1980-1986. Courses: General Zoology, I n v e r te b ra te Zoology, V erteb ra te Embryology, Mammalian Physiology, Environmental Physiology, Comparative Physiology

Research A s s i s t a n t , Louis iana S ta te U n iv e rs i ty , Department ofZoology/Physiology, Summer 1981-1986

Independent Research, U n iv e rs i ty of Washington, Friday Harbor Labs, Spring,1986

Research A ssoc ia te I I I , (E le c tro n Microscopy), Louisiana S ta te U n iv e rs i ty ,Department o f Zoology/Physiology, 1987

Lecture ExperienceDevelopmental Biology/Embryology, Mammalian Physiology, Comparative Physiology, Human Physiology, Environmental Physiology, General Biology, General Zoology, In v e r te b ra te Zoology, Entomology

90

91

Membership i n P ro f e s s io n a l S o c ie t ie s Am erican S o c ie ty o f Z o o lo g is tsAm erican A s s o c ia tio n f o r th e Advancement o f Science Am erican M a la c o lo g ic a l UnionSigma X i: The S c i e n t i f i c R esea rch S o c ie ty (F u l l Membership)L o u is ia n a S o c ie ty f o r E le c tro n M icroscopy A rkansas Academy o f S c ien ce

M isce llan eo u s E x p erien ce1 . E ig h t y e a rs (1978*1986) a c t iv e r e s e a rc h ex p e rien ce in scan n in g e le c t r o n

m icroscopy (Cam bridge S*600 and H ita c h i S-SOO SEMs) and t ra n s m is s io n e le c t r o n m icroscopy (RCA, H ita c h i HU-11, and JEOL 100CX Terns).

2 . P r e s id e n t , Zoology & P h y sio lo g y G rad u ate S tu d en t O rg a n iz a tio n (ZPGSO), L o u is ian a S ta te U n iv e r s i ty , 1984*1986

Honors and Awards Deans L i s t , U n iv e r s i ty o f A rkansas N a tio n a l Deans L i s t P h i Kappa P h i Honor S o c ie tyM artha Couch G ivens Award in B io logy , U n iv e r s ity o f A rkansas N a tio n a l R e g is te r o f O u ts tan d in g C o lleg e G raduates Who's Who among S tu d e n ts i n Am erican U n iv e r s i t i e s and C o lleg es R.A. L eF leu r F e llo w , L o u is ia n a S ta te U n iv e r s ity A rceneaux M em orial Award f o r R esearch in E le c tro n M icroscopy

U nderg radua te B io lo g y C ourses B io lo g y , M ic ro b io lo g y , B otany, V e r te b ra te Zoology, In v e r te b r a te Zoology, Mammalian P h y s io lo g y , M icro tech n iq u e (L ig h t , SEM & TEM), H is to lo g y , Embryology, Anim al B eh av io r, Entom ology, P la n t Taxonomy, N a tu ra l H is to ry o f V e r te b ra te s , G e n e tic s , C e ll B io lo g y , C om parative V e r te b ra te M orphology, P a leo n to lo g y

G raduate Z o o lo g y /P h y sio lo g y C oursesP ro to zo o lo g y , C om parative P h y sio lo g y , E nvironm ental P h y sio logy o f E s tu a r in e A nim als, M arine E cology , C e ll P h y sio lo g y , N eurosensory P h y sio lo g y , H is to c h e m is try , P o p u la tio n G e n e tic s , S cann ing E le c tro n M icroscopy, T ran sm iss io n E le c tro n M icroscopy, Advanced C e l lu la r T echniques in E le c tro n M icroscopy, I n v e r te b r a te Embryology (F r id a y Harbor L a b o r a to r ie s ) , L a rv a l Ecology (F r id a y H arbor L a b o ra to r ie s )

M isce llan eo u s G rad u ate C oursesB io ch em is try , E x p erim en ta l S t a t i s t i c s , SAS Seminar

R esearch I n t e r e s tE nv ironm ental P h y sio lo g y and Embryology o f M arine and E s tu a r in e Anim als

F in a n c ia l S upportSigma Xi G ran t i n A id (N a tio n a l H ead q u a rte rs - $325.00; LSU C h ap te r- $250 .00) f o r d i s s e r t a t i o n re s e a rc h (1986)

P u b lic a t io n sR o l le r , R .A ., D.W. G arton and W.B. S t i c k le . 1984. R eg en e ra tio n o f th e

p ro b o s c is , r a d u la and o d o n to p h o ra l c a r t i l a g e o f th e s o u th e rn o y s te r d r i l l T h a is haemastoma c a n a l i c u l a t e (G ray )(P ro so b ran ch ia : M u ric id ae ) a f t e r am p u ta tio n . Am erican M a lac o lo g ic a l B u l le t in 2 :63*73.

1976-19801979-1980

19791980 1980 1980

1981-19861982

92

Carton, D.W., R.A. R o l le r and J . Caprio. 1984. Fine s t r u c tu r e and v i t a l s t a i n in g o f the osphradium o f the southern o y s te r d r i l l , Thais haemastoma c a n a l i c u l a te (Gray)(Prosobranchia: M uric idae ) . B io lo g ic a l B u l l e t i n 167:310-321.

R o l le r , R.A. and W.B. S t i c k l e . 1985. E f fe c ts o f s a l i n i t y on l a r v a l to le ra n c e and e a r ly developmental r a t e s o f four species o f echinoderms. Canadian J o u rn a l o f Zoology 63(7):1531-1538,

R o l le r , R.A. and W.B. S t ic k le . 1987. In t ra c a p s u la r development o f Thais haemastoma c a n a l i c u l a ta (Gray)(Prosobranchia: Muricidae) under l a b o ra to ry c o n d i t io n s . American Malacological B u l l e t in , ( in r e v i s i o n ) .

DOCTORAL EXAMINATION AND DISSERTATION REPORT

Candidate:

Major Field:

Title of Dissertation:

R ic h a rd A. R o l l e r

Z oo logy

S a l i n i t y E f f e c t s on th e D evelopm en t an d L a r v a l T o le ra n c e o f

F iv e S p e c ie s o f E ch in o d erm s

Approved:

L i z a * -Major Professor and Chairman

iJPU'- hDean of the Graduate

EXAMINING COM M ITTEE:

\

Date of Examination:

J u ly 7 , 1987

salinity effects on the development and larval tolerance

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