Linking freshwater habitat to salmonid productivity

Watershed Program1

1. NW Fisheries Science Center 2725 Montlake Blvd. East, Seattle, WA 98112-2097

Capacity and Survival Capacity

Maximum number of fish at a life stage that can be produced under average annual environmental conditions

Total surface area Instream habitat Food supply Water quality

Survival The number of fish that live between life stages

Flows Sedimenation Pollutants Water quality

Spawner recruit relations and the effect of altered capacity or survival

Number of spawners

Nu

mb

er

of r

ecr

uits

Spawner recruit relations and the effect of altered capacity or survival

Number of spawners

Nu

mb

er

of r

ecr

uits Change in capacity

Spawner recruit relations and the effect of altered capacity or survival

Number of spawners

Nu

mb

er

of r

ecr

uits Change in survival

Carrying capacity – life stage distinctions for fall & spring

chinookSpawning Fry

(<45mm)

Parr(45-70mm)

Smolt

(freshwater)(>70mm)

Smolt

(estuary/

nearshore)(>70mm)

Total habitat area

+/-, +/- +/- +/-,+/- +/- +/-,+/-

Food supply +/- +/- +/- +/-,+/-

Total habitat area Spawning capacity example - North Fork Stillaguamish

Total habitat areaNorth Fork Stillaguamish chinook spawning capacity

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

-2.0 0.0 2.0 4.0 6.0 8.0 10.0

Range

Es

tim

ate

d #

of

sp

aw

nin

g c

hin

oo

k

Total Area (m2)

Spawn Riffle area (%)

Spawn Pool area (%)

Spawn Glide area (%)

Riffle area (%)

Pool area (%)

Glide area (%)

Redd Size (m2)

Adults per Redd

0

50

100

150

200

250

300

350

400

450

0 25,000 50,000 75,000 100,000 125,000 165,000 190,000

Chinook redd capacity

Freq

uenc

y of

est

imat

e

Estimate w data source #1

Estimate w data source #2

Total habitat areaNorth Fork Stillaguamish chinook spawning capacity

How do we compare capacities among life stages and habitat types ?

habitat area × average fish density

n

1ii

n

1jij dAN

Aij = is the sum of areas of all habitat units (j

=1 through n) of type I.

di = density of fish in habitat type i.

Habitat type preference -juvenile salmonid use

Classification of habitat types allows assessment of fish use patterns and expansion to larger aggregate units (e.g., watersheds)

tribu

tarie

sm

ains

tem

side

chan

nel

pond

s

estu

ary

chinook(0)

coho (0,+1)

steelhead (+1,+2)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Juve

nile

sa

lmo

nid

/m2

How do we compare capacities among life stages and habitat types ?

Estimate (N) for each life stage in a given habitat

Multiply by density independent survival to smolt stage

habitat area × average fish density × survival to smolt

Smolt production potential can then be compared in terms of number of smolts ultimately produced.

Change in historic v. current coho smolt potential production

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

Skagit Stillaguamish

Co

ho

sm

olt

s Trib Loss

Mainstem Loss

Slough Loss

Pond Loss

Current

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

Skagit Stillaguamish

Co

ho

sm

olt

s Trib Loss

Mainstem Loss

Slough Loss

Pond Loss

Current

Range of current estimated v. measured coho smolt potential production

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

Stillaguamish(Pess

estimate)

Stillaguamish(Nelson

measuredCWT)

Skagit(Beechieestimate)

Skagit (Seilerscrewtrap)

Maximum

Mean

Minimum

Habitat preference – a change in freshwater rearing quality

There are 5.4 times as There are 5.4 times as many juvenile chinook many juvenile chinook salmon in natural wood salmon in natural wood banks as hydromodified banks as hydromodified banksbanks

Beamer et. al., 1998Beamer et. al., 1998

Expected change in juvenile salmonid abundance normalized to abundance in riprap (always = 1.0)

02468

101214161820

no c

over

boul

der

cobb

le

plan

ts

ripra

p

rubb

le

woo

d

w-

bank

root

sw

- deb

rispi

les

w-s

ingl

elo

gs w-

root

wad

s

Ele

ctiv

ity in

dex

Chinook (0+)

Summer rainbow (0+)

Summer coho parr

Winter rainbow (0+)

Beamer et. al., 1998Beamer et. al., 1998

From Beamer, From Beamer,

unpublished dataunpublished data

Habitat preference Chinook spawning

0

20

40

60

80

100

120

0 10 20 30 40

Pool spacing (Bankfull channel widths per pool)

Ch

ino

ok

sa

lmo

n r

ed

ds

pe

r k

m Forced pool-riffle

Plane-bed

Pool-riffle

Carrying capacity – Food supply and habitat capacity

Slaney and Northcote (1974) -Rainbow trout (0+) High prey density, less change in territory size

Giannico (2000) – Coho (0+) Food supply high – found in pools with little wood

cover Food supply low – found in pools with abundant wood

A small change in food supply can effect capacity by altering territory size and density of salmonids

Survival – life stage distinctions for fall & spring chinook

Egg to fry Fry to parr Parr to smolt Freshwater to estuarine/

nearshore

Temperature +/- +/- +/- +/-

Sedimentation +/- +/- +/- +/-

Food supply +/- +/- +/-

Flows +/- +/- +/- +/-

Water quality +/- (?) +/- (?) +/- (?) +/-

Peak flows and egg to migrant fry survival estimates - Skagit Chinook (1989-1996)

(Seiler & others 1998).

y = -4E-05x + 0.1745

R2 = 0.86

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

0 1000 2000 3000 4000 5000

Annual maximum discharge (cms)

Est

imat

ed e

gg t

o m

igra

nt

fry

surv

ival

Peak flow recurrence interval and egg to migrant fry survival estimates - Skagit Chinook

(1989-1996)

egg to fry survival = 0.1284e-0.0446(flood recurrence interval)

R2 = 0.97

0%2%4%6%8%

10%12%14%16%18%

0 20 40 60 80

Flood reccurence interval (years)

Est

imat

ed e

gg t

o m

igra

nt

fry

surv

ival

Chinook recruits/spawner v. flood recurrence interval

0

1

2

3

4

5

6

7

0 50 100 150Flood recurrence interval (FRI) (years)

Chi

nook

rec

ruits

per

spa

wne

r

Cascade summer runLower Skagit fall runUpper Skagit summer runUpper Sauk spring-runLower Sauk summer-runSuiattle spring-runStillaguamish summer-run

A change in peak flows in the North Fork Stillaguamish

y = 180.82x - 331389

R2 = 0.29p < 0.001

0

200

400

600

800

1000

1200

1920 1940 1960 1980 2000

Year

An

nu

al m

axim

um

d

isch

arge

(cm

s)

A change in peak flows in the North Fork Stillaguamish

0

200

400

600

800

1000

1200

1 10 100

Recurrence interval (year)

An

nu

al m

axim

um

d

isch

arge

(cm

s)

1972 to 19951950 to 19711928 to 1949

Sensitivity of regression to changes in peak flows in the North Fork Stillaguamish

0%

2%

4%

6%

8%

10%

12%

14%

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

Recurrence interval (year)

Est

imat

ed e

gg to

fry

surv

ival

Survival for 1928 to 1949 flow conditions

Survival for 1950 to 1971 flow conditions

Survival for 1972 to 1995 flow conditions

Survival – Scour? Entombment? Oxygenation?

Downstream displacement?

0

0.2

0.4

0.6

0.8

1

0 10 20 30 40 50

Scour depth (cm)(could also be fines %, peak flows (cms))

Est

imat

ed e

gg

to

fry

su

rviv

al (

%)

Survival – peak flow caveats

Cannot break down survival by mechanism Keep mechanisms lumped

Egg to fry Entombment Scour Oxygenation

Fry to smolt Predation Downstream displacement

Different relationship in Columbia River Basin Rain-on-snow v. snow-dominated

Survival – Food supply

Slaney & Ward (1993) – Steelhead (1+,2+) Increase in phosphorus & nitrogen

Increase in smolt to adult survival (1+) - +62% Smolts – +30% to 130%

Being clear about assumptions and model choice

Do a sensitivity analysis where possible

Run multiple scenarios with different datasets

Many relationships are not universal Puget Sound v. Columbia Basin flow example

Keep it simple Do not assume cause and effect mechanism unless it is clear

Egg to outmigrating fry example

Keep numbers local where possible

Check model numbers against real fish numbers