34th ANNUAL FISH CULTURE CONFERENCE

Moscow, Idaho, December 7-8, 1983

mlh #4 11/28/83

TITLE: Growth and seawater tolerance of fall chinook smolts (Oncorhynchus tshawytscha) after prerelease treatment with formalin and potassium permanganate.

BY: Stanley D. Smith, USFWS Seattle National Fishery Research Center Marrowstone Field Station Nordland, WA 98358

Rowan W. Gould, USFWS National Fishery Research and Development Laboratory R.D. No. 4, Box 47A Wellsboro, PA 16901

Wally S. Zaugg, NMFS Northwest and Alaska Fishery Center Cook Field Station Cook, WA 98605

Lee w. Harrell and c.v.w. Mahnken, NMFS Northwest and Alaska Fishery Center Manchester Field Station P.O. Box 38 Manchester, WA 98353

In trod uc tion

For many years Federal, State and private salmon and trout hatc her ies have used various medications to treat the many maladies incurred by stocks of fish in crowded rearing systems. Among the more common drugs used f o r therapeutic and prophylactic treatments are formalin and potassium permanganate (KMn04)

Formalin ( 37% by weight formaldehyde) is used. extensively for the control of ectoparasites. Although formalin toxicity is infrequent in young salmonids, treatment with a 1:4000 dilution in water warmer than 10°C can cause a loss if the fish have bacterial gill disease (Wood 1974). Piper and Smith (1973) found, after conducting an extensive survey of 74 United States hatcheries, that few problems developed from formalin toxicity if the chemical was properly used. Wedemeyer (1971) observed that the prescribed dosage of 1:6000 for ectoparasitic treatment caused a significant drop in blood Cl-, ca++, t o tal co2 , and tissue vitamin C levels in rainbow trout (Salmo gairdneri). However, coho salmon smolts (Oncorhynchus kisutch) were less affected. Bouck and Johnson (1979) found that formalin treatments produced low level mortality i n coho salmon smolts upon direct transfer to seawater and no mortality after four days delayed transfer to seawater.

KMno4 has been used quite regularly since 1904 for the treatme nt o f numerous parasitic outbreaks. TJse of the drug has also been effective against bacterial gill disease, providing certain precautions are taken; i.e., allowing for temperature variations and changing of rear i ng water (Wood 1974). Tucker and Boyd (1977) stated that varying organic load levels caused incon s i s t e ncies in effectiveness aqainst bacterial gill disease , and that the value o f t he compound in the aquatic environment is inversely proportional t o the l oad o f the oxidizable organic matter in the water. Jee and Plumb (1 98 1) observed that the effectiveness of KMn0 4 was much greater when treating fathead minnows (Pimephales promelas) infected with Flexibacter columnaris in organically depleted tap water vice organically enriched po nd water. Bo uc k and ,Johnson ( 1 979) indica ted that presecribed trea tments with KMn04 caused a n 80% mortality in coho salmon smolts when the fi s h were tr a nsfer r ed to 28 parts per thousand (ppt) seawate r i mmed ia t e ly a fter trea tm e nt. However, if the fish were held for four days post-treatment in freshwater, the morta l .i. ty rate dropped t o 12%.

At present, formalin is registered with the FDA as a parasi t icide and KMno4 has been exempted from regi s tratio n (Sc hnick a nd Meyer 19 79).

Our objective in these stud ies was to determine if tim i ng and medica t.i. o n treatment effects smoltification as meas ured by g ill Na+K+ ade nosine triphosphatase (ATPase) activity, sea wa t er survival and g r owth.

154

Methods and Materials

Experimental Animals

In both the 1981 formalin study and the 1982 KMn04 study, eyed fall chinook eggs were transported to the USFWS, Seattle Nation~l Fishery Research Center's Marrowstone Field Station in October, disinfected in a 1:100 solution of Argentine1/ (an iodine base disinfectant) and reared to swim-up in an eight tray Heath-Tecna incubator with a fresh water flow rate of approximately 3 gallons per minute (gpm).

In February, the fry (weighing approximately 450/lb) were placed in 68-liter rectangular glass aquaria in lots of 50 with each aquarium receiving about 1 liter per minute fresh water. The fry were allowed to acclimate t o their new surroundings for about two weeks prior to commencing treatments.

Experimental Design

For the 1981 formalin study, the aquaria were randomly divided in t o two groups~ 103 for formalin and "sham" treatment controls and ATPase analysis and 10 for unhandled, untreated controls. Of the 58 aquaria in the KMn04 study, 36 were randomly divided into two groups~ 18 each for KMn0 4 treatments and "sham" treatment controls. Of the remaining 22 aquaria, four were used as untreated, unhandled controls and 18 were used to monito r ATPase activity. Bi-weekly treatments were begun in February and continued through May (Figs . 1 and 2). ATPase analysis was conducted according to Zaugg (1982).

Once smelting was determined by gil ATPase activity analysis, the fish were acclimated to 28 ppt seawater by exposure to 12-15 ppt seawater (isoto nic) f o r 48 hrs for formalin treated fish and 24 hrs for KMn0 4 treated fish. Once the acclimation period was complete, the fresh water was turned off and the seawater flow rate increased to approximately 1 liter/minute. In both studies, smoltification occurred in May. Mean loading densities at the time o f seawater entry in 1981 and 1982 were 4.1 gm fish and 4.6 qm fish per liter of water respectively. Lightinq was simulated to approximate the natural photoperiod by weekly adjustments to overhead florescent lamps.

The 1981 formal i n treatments were conducted according to Wood (1974) using a 1:6000 dilution in static fresh wate r for one hour. KMn04 treatments in 1982 were also according to Wood (1974) using 2 mg KMno 4 per l iter static fresh water for one hour each on three consecutive days. In both studies the aquaria were not drained at the end of the treatment, but thoroughly flushed with fresh water. In both studies, "sham" treatments were conducted in static situations and stirred as i f the medications had been used.

1/Reference to trade names is for identification only and does not imply U. S . Gove rnment endorsement of commercial products.

All study fish were fed once daily to satiation with OMP II. However, feed was withheld for 24 hrs prior to KMn04 treatments to reduce the organic load.

Microbial Examination

In both studies, all post treatment mortalities, other than those which were lost to system failures, were examined microbiologically for pathoge~s using sterile brain heart infusion agar and asceptically removed kidney rna terial.

Results

Na+~+-ATPase Activity Analysis

Some significant differences at the 95% confidence level did occur in formalin treated fish when compared to their "sham" treated controls using a "t" test for comparison. ATPase activity was analyzed for those fish treated 60 days or less prior to seawater entry (Figs . 3-7). However, the enzymes' activity was not consistent in those groups; i.e., when Group 2's activity was monitored on May 7, one day before seawater entry (Fig. 4), the treatment group was lower than the control but when Group 6 was monitored on May 7, the treatment group was higher than the control (Fig . 7). When Group 6 was again analyzed five days after seawater entry, the treatment group was lower than the control.

ATPase activity in KMno4 treated fish responded similarly to the formalin treated fish. Significant differences at the 95% confidence level occurred between "sham" treatments and unhand led, untreated controls (Fig. 8) and between treatments and unhandled, untreated controls (Fig. 9). However, the treatment and "sham" treatment groups were consistently lower than the untreated, unhandled controls.

Growth and Seawater Survival

No significant differences occurred in growth and seawater s urvival (20 day challenge) in the formalin and KMn04 treated fish when compared to their respective "sham" treated g roups and unhandled, untreated controls .

Mortalities, post seawater exposure, were practically none in both studies for treatment and control groups. Formalin treated fish demonstrated ~ 97% survival and KMn04 treated groups were~ 99% (Figs. 11 and 12).

Discussion

The inconsistencies observed in the ATPase activity of the formalin treated fish indicates that something may be occurring during the smolti f ication process with recently treated fish, but given the good growth and seawater performance, it may not be enough to cause alarm. We feel the important point to remember is that the ATPase levels, when compared between treatments, "sham" treatments and unhandled, untreated controls over time, d i d rise as expected, the fish did convert to 28-29 ppt seawater and did survive very well (97% overall) for at least 20 days (Fig. 11).

KMno4 treated fish were also determined to be unaffected by the treatments and demonstrated a 99% survival after 20+ days on seawater. Even when technical problems were included in the losses, the survival rate was 94% (Fig. 12). The 12 deaths in the KMn04 group that did occur post seawater acclimation were determined to be those fish not able to cross the fresh to seawater threshold. The mean fork length of the 12 was 20 mm less than that o f the survivors. Again, the point to remember is that even though a few significant differences did occur in ATPase activity, the young smelts did very well when acclimated to seawater. However, a possible latent ATPase rise ma y be occurring if the fish are treated with KMn04 20 days or less prior to seawater entry.

In conclusion we feel that when properly used, formalin and KMno4 will not affect the ability of smelts to enter seawater. However, care sho uld b e taken when using the chemicals because if i mproperly used, both c he mical s could cause unnecessary damage to the health of the workers and the fish. Also of importance is the fact that this was a laborato ry s ituation a nd the e nvironmental factors at var i ous rearing facilities may cause somewha t va r ied results when using the drugs.

1 c:-7

Literature Cited

Bouck, G.R., and D.A. Johnson. 1979. Medication inhibits tolerance t o seawater in coho salmon smolts. Trans. Am. Fish. Soc. 108(1 ):63-66.

Jee, L.K., and J.A. Plumb. 1981. Effects of organic load on potassium permangenate as a treatment for Flexibacter columnaris. Trans. Am. Fish. Soc. 110:86-89.

Piper, R.G., and C.E. Smith. 1973. Factors influencing formal toxicity i n trout. Prog. Fish-Cult. 35(2):78-80.

Schnick, R.A., and F.P. Meyer. 1979. Announcement of compounds registered for fishery uses- Special report. Prog. Fish-Cult. 40(1 ):36-37.

Tucker, c.s., and C.E. Boyd. 1977. Relationships between potassium permangenate treatment and water quality. Trans. Am. Fish. Soc. 106(5):481-488.

Wedemeyer, G.A. 1971. The stress of formalin treatments in rainbow trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch). J. Fish. Res. Board Can. 28(12):1895-1904.

Wood, J.W. 1974. Diseases of Pacific salmon: Their prevention and treatment. State of Washington, Dept. of Fisheries. Hatchery Div. pp. 10-11, 13-15.

Zaugg, w.s. 1982. A simplified preparation for adenosine triphosphatase (ATPase) determination in gill tissue. Can. J. Fish. Aquat. Sci . 39:215-217.

Figure 1.

Date --Feb 26

Mar 2

Har 26

Apr 9

Apr 23

May 7

Experimental procedur e tn te s t th e effec t n f f .') rmalin treat;:J e nt growth, and freshwater-seawater tran s ition o f fCJ.l1 chinook salmon.

"' + . + . -· on ,.,:1 - L ;_; 1l ;

TREAr1ENT PHASC ll,\ TE COLLEC:TIO~·l ~' lL\Si~

Date and !! Tanks Sa:n plc-1 l + + ' f o r fish ~J a - K g i 1 1 AT P a s e a c t i v i :: y n n rl r: r u \.J t h

II Tanks Treatment Treatcd

3

Formal in b

11 Controlc 11

Formalin 10 Control 11

Formalin 9 Control 9

Formalin 8 Control f3

Form a l in 7 Control 7

Fonnal in 6 Control 6

Non-Treatment, 10 Unhandled Control

a Each tank contained appro xima t ely 50 fish.

b Treatment procedures were according to Wood (1979).

c Control fish were handled exactly the same as fish exposed t o forr.~a] in.

.\T Pase act ivity.

' la t e and II Tanks converted to

s ea1va ter inflow

:1ay 17- ~ay 19e

5 5

5 5

5 5

5 5

5 5

5 5

10

d Thirty fish, ten pools of three , were sampl ed for Na +- K+ gil l ATPa ~;e ac L iv l ty . the nearest 0.1 gm and men su red (fork length) to the nea re s t mm.

Ench fish 1.;as weighed to

e Fish were exposed to 12-1 5 ppt sa linity on Hay 17 and convert ed tu ~C) ppt ,.;:1linity on :· !c:; v 19. survival 1vas mon it ored fot- 20 day s .

.·

Sea1va ter

(J\

Ul .--<

GROTJP NO.

l

2

3

4

5

6

.L J..UUJ.'\.J.::.. .L. •

EXPT~RIHENTAL DESIGN, AQTJARIA ALLOCATION AND SAMPLING TH1ES TO DETERMINE THE IMPACT OF KMn04 TREATMENTS ON FALL CHINOOK SAU10N SMOLTIFICATION AND SEAWATER SURVIVAL

0:

1! AQTTAR.IA TR~l.\'I'MEN'T'

USED

3 3 1

3

3 l

3 3 l

3 3 1.

3 3 l

4 4

3 3 l

4 4

KHn0 4 SHAM STOCK

KMn0 4 SHM~

STOCK

KMn0 4 SHAM STOCK

'f<Mn0 4 SHM-1

STOCK

KMn04 SHAM STOCK

KMn0 4 SHAM

KMn0 4 SHAM STOCK

KMn0 4 SHAM

w

l

1982- - 2/25

FH70 I I

SSAH20 1------)1 I

j ,----41 I

----------------------------~' ''------~ I I

-------- --~

[1

I

3/ll

I I I I

~------------------~~ I ;::::;------------~ _.,-------"~ []

I

3/25

111 )_" I 1

lJ')

I ' ir-f

@) m 1d )d

I

4 / 8

rj __ _ --1.9' m

I

~]I ~rol

I

HI . (!) I +JI ; r0 1

3: ' .--l rtl '

._I~~ [] IHI __ _

ffi-l ;:j l

~·g 1~1 j''JI

I I

4/22 5/6 5/7-8 6/l

Q w 0::: ;::J Cf)

.:r: w :2

c: z .:r: Q w

z::r:: Ol'.J HH E- : ~1 .:r:::.s: z HC!l

~~ w:> 1:--tH

:> p:; ,_, ,_ Cf)

H H .:r:

INDICATES ALL FISH IN NUMBER OF AQTJARIA INDICATED WERE TERMINALLY SAMPLED FOR FORK LENGTH, WEIGHT AND GILL Na+K+-ATPase @ 50 FISH PER AQUARIA

c \C

FIGURE 3. COMPARISON OF GILL Na+K+-ATPase ACT IVITY BETWEEN TREATMENT AND CONTROL GROUPS TREATED WITH FORMALIN. VALUES ARE MEANS :!: STANDARD DEVIATION. 30 FISH \.-JERE SAMPLED FOR EACH VALUE INDICATED.

CD: CONTROL CJ : TREATED WITH FORMALIN

24

22

20 l 9 M I I 0:: 18 I :::J

~ 0 ::r:: 16

M + 9 I I ..--<

14 + \.()

;::..;z; ..--<

E-<H HW

9 >E-< 12 HO +¢ .,9 E-<0:: +9 UP..

,:t: 10 tJI <lJ E Ul• rU · .-i 8 p...p...

E-< ,:t:U) Ill.-' 6 + .....:1 GROUP 1

:>::0 DATE TREATED + ::s I rU ::l 4 FRESH H20 SEA H20 z - I I

I I (28-29 ppt)

l 2 I

l ..J.-

1981 - 2/2 6 3/12 4/9 4/23 5/ 7 5/21

,·

FIGTJR8 4 COMPARISON OF GILL Na+K+-ATPase ACTIVITY BETWEEN TRE~TMENT AND CONTROL GROUPS TREATED V'HTI1 FOP-MALIN. VALUES ARE MEANS :!:: STANDARD DEVIATION. 30 FISH WERE S~~PLED FOR EACH VALUE INDICATED.

ID: CONT?.OL 0 : 'T' P.EATED VJI TB FOm1ALJN

2.1

22 I

I

20 r + ~+ rl

18 I I ~ 0 0 9 ::r:: 16

('

rl \.l I

!>-< z 14 +9 E-i H H ~-1 :>8

12

++ H O 8~ UP-< .:C

10 l +cp tJ1 (j) 8 Ul • m·ri 8 p...p... 8 .:CU'J l ii:1 6 + H

::>::0 GROU P 2 + :::8 DATE TREATED FRESH H?O I SEA H 0 m ::l 4 2 z- - I I (28 - 29 ppt)

I I I

2 I

I

"' u 1981 - 2/26 3/12 4/9 4/23 5/7 5/21

..--i I ~ ::::> 0 :I:

.-1 I

:>-I:Z E-!H H ~'-1 > f:--i HO E-1~ UP-. .:r:

tJ'I (1) 8 Ul • rU ·rl 1=41=4 E-1 .:t:U) I~

+ H ~0 + ~

rU ::l z-

FIGTJRE 5. ~OMPARISON OF GILL Na+K+-ATPase ACTIVITY BETWEEN TREATMENT AND CONTROL GROUPS TREATED WITH FORMALI N . VALUES ARE MEANS ~STANDARD DEVIATION . 30 FIS H WERE SA1,1PLED FOR EACH VP,LUE INDICATED.

11.1: C:ONTROL 0 : 'I'REATED WITH FORI'1ALIN

24 ~ 22

I I

20

18 r :r~ 16

+ +? ? 14 r I

12

:0 ~ + ~

6

f

GROUP 4 FRESH H20 I SEA H2 0 4 DATE TREATED I (28-29 ppt) I I I

2 I

I ~

L I 1981 - 2/2 6 3 / 12 4/9 4/23 5/ 7 5 / 21

(Y")

~ .....-<

FIGTJRE 6. COMPARISON OF GILL Na +K+ - ATPase ACT I VITY BETWEEN TREATMENT AND CONTROL GROUPS TREATED WITH FOPJ-1ALIN. VALUES ARE MEANS 2: ST.ANDARD DEVIATION. 30 FISH v~ERE SN1PLED FOR EACH VALUE IND I CATED.

18: CONTROL CJ : TREATED WITH FORMALI N

2.1 ..-- '

I 22

20 ..-1

~ I p:: 18 ::J I 0 ::r: 1 6 + I

9 I -0 ..-1 + 'J: I

14 :>iZ ¢ f-lH H~ :>f-l

12 H O 80:::

1 0 t ¢ uo..

~ tJ'I

Q) 8 Ul • rd ·rl 8 0.. 0.. E-; ~(/)

I ~ 6 + t--4 ~0

+ :8

~ FRE SH H20 I SEA H20 rd ::J 4 I z ~ (28 - 29 ppt)

GROUP 5 I

2 ~ DATE TREATE D I I ~

198 1 - 2/ 26 3/ 1 2 4/9 4/23 5/7 5/ 21

FIGURE 7 . COMPARISON OF GILL Na+K+-ATPase ACTIVITY BETWEEN TREATMENT AND CONTROL GROUPS TREATED WI TH ~FOffi.1ALIN. VALUES ARE MEANS 2: STANDARD DEVI ATION. 30 FISH vJERE

"" SAMPLED FOR EACH VALUE I NDICATED.

8: CONTROL 0 : TREATED ~'HTH FORMALIN

24

22

20

f :t H I p::; 18 8 0 ..... ....... 1 6 .

I 9 lfl H ~

I 14 +

I ..--;

!>-<Z f:4H H ~ :>1:4 HO 12 1:4 0::: UP. .::r:

1 0 r GROUP 6 tJ1 Q.J 8 DATE TREATED Ul • ctl ·rl 8 P-< P-<

1:4 tct:Cfl

I ~ 6 + ~ ~0

+ ::s

~ I

ctl ::J 4 F RESH H20 SEA H20 z ~ I I (28 - 29 pp t )

I ' 2 I ..J-

1981 2/26 3/12 4/9 4/23 5/7 5/21

24

22

20

~

I 18 o::; ;:::, 0

16 -~ .... . .-i

I >~ z 14 E-• H H (Lj >[-I HO 12 [-I C:::: CJP-< ·~

tJl 10 <1J E Ul • C1j •rl p_,p., 8 E-1 ,::C (/) IW

6 + ....:I :-<:;0

+· :8 rd :::l

4 r-.7 _... ,_,

2

FIGURE 8. CO:lP _:;RISON OF GE,l. N a +l(+ - l._T Pa se !'\C 'I' I"JITY B CT~'iY:~!..:N ...-. P E 7 'T -'" ' 7 I'T' '' T~" l\7 - , '1 - -TJ-.' :'\PE ' F'A' ' ~ + , , .,.,.,,,D " -.-1 ~ . • A .i:, •J 1'11 .:-1 ·\1Tl ·1C 4 . · HL t~::O : • .-'J . ' . . :. _ ,, ~ - .::. _..,__,hl<.:....

USED FO ~~- E r...r ..: :1 'JT,LT_T !~ T~miC.I\Ts D.

151 : CONTRCJ L 0 : T ?C_T.\.TED P I Til K:T'.~;') 4 (SHAM)

I L I i f-I I

t i

+ I

[ +

I

~ t t

t

TfJ~ '\ 'IT S~; '~ .~,-m C•J!·JT SJ) I, C ~' _. ~J p ;:;

:J'C::'.' I i'.?I O ~ J.

f 5+ I

5

FRESH H 20

• .1 ~~ .0_~ .. 1 P L· G ;.; ~~: ·~: ·c~ E

• ~ I I

6

-s n LI 0 ~ g ~a · ~ ~ ,: - ~ [ 2 - L I L _/ I.) f-l L

L __ _L L

3/11

----'---· - - ___ _ __ _L _ ·---- --- - - l_ _ _ ____ ______ ___ _L__ _____ _J__ ___ _

2/2 s 4/8 - . ..., c ,,. j 3/ 2 5 -1/2 2 5/E - 8 s;:) 1

1 9 8:'.

\! \!

24

22

20

r-1 I 18 cr: ·~ >-'

0 16 •'-<

r-1 i

::-l z 14 E-1 H H~ >8 HO 12 8 p~ CJP.. «

tn 10 ([) E UJ • m ·rl p.,p., 8 8 ~U) I~

6 + ..:1 ~0

+ :E m ::J

4 z-

2

FIGURE g. COf·1P.;RI S O:-..J OF GILL Na+ K+ - Fl' J? ase l\CT I VI'I'Y BS ·n,n:::;::;~J TPI~~T i ?NT .i'\:;JD COTJ'ROL G?.OUPS '1'[-;.~J· "'l'T;'r', ''7I'T' e T' NO \ 7 1, ~· fJP~ i'\PE ~,1,.7'•·s + 'C 'T'""'DAP ' ' " """T "-:'T t' ' ·l l r·. · ~ TJ. \·!•.) r r.s r•"'''"E '- . Jl""\ . · .. J \' LJ. l \m <.l • ~ .. .LJ..__.~ • . , .J •• • JL"'\. . \1 - .._.1: .'--"\.~ ... . _.JJ . _j ';_ r•.,_ ~ -~ -- . . . ;.__, .._ , L _ .._.&....! J....I o~ ! t .' . \.

USSD FOR EACI '.Ji,T.,UE FWICAT C'J .

-: \.ONJ:'ROL 0: TREATCD PI TH Y- :nN0 4

~ ~ ~ I ,-

l I

I t-I

f + I t t

~ L_l

}./ 2 ~~ 3/ 11 3/25

6

+ 5 + 5~

fRESH H20

___ . __ L ___ _

4/ 8 4/ 22

1 98 2

_ L__

S/E - 8

I ,. +

' ., E i'l " 0 2 8 '; o ,_ 0 •, i - l1 2 - - I ~ .,/ [.J IJ L

_.__ _ _______ l ___ _

.S / 21 6 /3

r-­~ .--<

E 8

100

90

80

::r: 7 0 E-i l? z ~ H

~ 60 0 ~

50

40

FIGURE 10. COMPAFUSON OF GROWTH (FORK LENGTH ) BETi'iEEN KMnO 4 TREATED, SHP.J-1 TREATED AN D CONTROL FALL CHINOOK SMOLT S. SAEPLES SIZE S ARE >20 ~HTH HOST > 30.

GROUP NO. 6

a Indicates Significant Difference at the 0 . 95 Confidence Leve l

-: CONTROL 0 : TREA'l'ED ~11TH KMn04

~: SHAM TREATED

+ t + +

I • I

+

FRESH H20

I I I I I I I I I

t a

SEA H2

0

~ I L ! I II I

2/11 2/2 5 3/ 11 3/25 4/ 8 4/2 2 5/G 5/21

19 8 2

L I I

I

6/ 8

co \,()

..--<

Fi g ur e ll. Seawat e r challe ng ~ survival (20 ,! exn o su r e) o f f a ll chin oo k .s :1lmon tre a t ed o r sha m-tr e ,1 [ e d (control ) with for~al i n at differen t t i m~s pr i n r t 0 seawa t - ~ r c nt ~v .

I·: a n ·? ~ i n n :.~ r c (·r:. t

llumber To t <1 l T0t al Sun: iv a ] r ,) ta 1 T n : a tm e n t T;mk s pe r ·:urnh.' i .-J:

1 ~: um he:. nF F, P t ~.: c C'. n Pe r c c a t

Da !~81) Tr ea tme nt T:: e a tmc n l f' i sl : Ch a 1! e nc~ c ~~ ) :: 1 lt"Vi'.' O r ~; Ta nks ;..; ~! r ·.r i ~/;] 1 - ----- ·- --- --- -··- - -- --- -·-- -------

Feb 26 formal in 5 23q . ) ~- : .... ....)· 1 l fJ iJ~( - Jh /. g p ~·

Contr o l 5 239 n:. 1 ou~< - 9 ) ·;:. 9R~~

~!a r 2 Form a l in 5 23'1 : ~ 3 ·_) l tYJ/, - 9 ~ ~~ 97% Co ntrol I d

'I ' 81 lh 98 !>•J :,·':, ')6%

.'"la r 2 6 Formal in 5 2 :j 5 ~ ·:, \ <J 3?-9 J/, 96 ~~

Control 5 249 '1 .'. l 1 0 0~< - 9 <:; :/ 97% - -t .:.

;\p r 9 Form a l in I a -~ ~0~ l fJ'l lOU / - '·J-'17 96 '/,

Co ntr o l 5 266 } ) S 9:3~~ - ~ 2? 9fJ );

Apr 2 3 Fo rmal in 5 ? , ' 2 1 l l 00 1- 94 ~~ 98% -1 0

Co n trol I a 200 I ~•7 l () 0 >;- 9 6 ~; 99% 'I

~!ay 7 Fo rmAl jn 5 245 2 3 ') 1 ou?> 94 ~< 98% Co ntrol 5 :.?.4 !1 2 4:J l 00"!': - C) f) 'l, 98%

NO TREA TI1ENT 10 48 1 41) 5 1 oo ~; - g r; 97?,

a Fish in t a nk wr:' rc lost due t o a c eidental water t:hut ·- o ff.

b Totnl numb e r s of fish in the tank..s not equaLling multiple r of SO .Jrc 2 ttr ib11t eJ to e xp e rimental ( c ounting) error a nd "jttmp-outs."

0' \,()

..--<

FIGURE 12. SEAWATER CHALLENGE SURVIVAL (20+d EXPOSURE) OF FALL CHINOOK SALMON TREATED OR "SHAM" TREATED (CONTROL) WITH KMn04 AT DIFFERENT TIMES PRIOR TO SEAWATER ENTRY.

RANGE IN PERCENT

NUMBER TOTAL TOTAL SURVIVAL TOTAL TREATMENT TANKS PER NUMBER OF NUMBER OF BETWEEN PERCENT DATE ( 8 2) TREATMENT TREATMENT FISH CHALLENGEDb SURVIVORS TANKS SURVIVAL -

Feb 25 KMn0 4 3 149 149 - 100 % Control 3 149 149 - 100 %

Mar 11 KMn0 4 3 150 147 100 %-98 % 98 % Control 3 150 150 - 100 %

Mar 25 KMno 4 3 149 148 100 %-98 % 99 % Control 2a 128 124 100 %-94 % 97 %

Apr 8 KMn04 2a 137 137 - 100 % Control 3 149 141 98 %-90 % 95 %

Apr 22 KMn0 4 3 150 147 100 %-96 % 98 % Control 3 150 145 100 %-90% 97 %

2a 133 May 6 KMn0 4 133 - 100% Control 3 150 148 100 %-96 % 99 %

a Fish in tank lost due to system failures post treatment date.

b Total number of fish in tanks not equalling multiplier of 50 are attributed to experimental (counting) error and "jump-outs''.

c r-