Reduced Recruitment Performance in Natural

Populations of Anadromous Salmonids Associated with

Hatchery-reared Fish

Pacific Coast Steelhead Meeting – March 14, 2012

Mark Chilcote (USFS), Kevin Goodson (ODFW), Matthew Falcy (ODFW)

Oregon Recovery Planning

Quantitatively describe threat impacts to viability

Hatchery threat difficult to describe

Literature review of limited help

Studies of Reproductive Success (RSh)

Number of offspring produced per hatchery spawner relative to number produced per wild spawner

Evidence from 3 studies (all steelhead): Leider et al 1990 (Kalama River) McLean et al 2003 (Forks Crk,

Washington) Araki et al 2007 (Hood River)

RSh averaged about 0.10 for segregated stocks and 0.60 for integrated stocks

Supposition

IF reproductive success of hatchery fish (RSh) spawning in the wild is low,

THEN, should see evidence of this from recruitment performance

Relationship from Chilcote 2003*

y = -1.97x + 1.41R2 = 0.70

-0.50

0.00

0.50

1.00

1.50

0.00 0.25 0.50 0.75 1.00

Ph

Intr

insi

c P

rod ..

* Chilcote, M.W. 2003. Relationship between natural productivity and the frequency of wild fish in mixed spawning populations of wild and hatchery steelhead (Oncorhynchus mykiss). Can. J. Fish. Aquat. Sci. 60: 1057-1067

2011 Analysis – Key Questions

Does relationship hold for all populations?

Does it apply to other species (coho and Chinook)?

Is it sensitive to type of hatchery fish? Integrated versus Segregated

Two-Step Process

1. Estimate intrinsic productivity through fitting recruitment curves to data sets

2. Determine what variables (covariates) account for most of the variation in intrinsic productivity

Recruitment Model Fits

Looked at 93 populations From Washington, Oregon, Idaho

Fit recruitment model for 89 of these

Therefore, intrinsic productivity estimated Chinook (37), steelhead (29), and

coho (23)

Populations Well Distributed

Step Two

Develop productivity models with multiple covariates

Compare models Identify model that best explains

variability

Covariates

Species Hatchery location Hatchery program type

(integrated/segregated) Hatchery legacy Dams Proportion hatchery spawners

(Ph)

Models Considered

Covariate

Model

12

9 1 7 8 11

10

4 2 6 3 5

Ph X X X X X X X

Species X X X X X X X X X X X X

H type X X X X X X X

H legacy X X X X X X X

H location

X X X X X X X X

Dams X X X X X X X X X

Ph:Species

X X X X X

Ph:H type

X

BIC 144

148

157

161

166

170

175

211

215

218

230

239

Best Model Covariates

Covariate Sum of Squares

Ph 41

Species 13

Dams 7

Hatchery location 2

Best model did not include hatchery type or legacy

Modeled Relationship

Chinook – Coho – Steelhead -

Findings

The model explained 72% of the variability in the data

The slope suggests that productivity of 100% hatchery fish is 13% that of 100% wild fish

There was no relationship with integrated versus segregated broodstocks

Mechanism(s) Unknown

Analyses didn’t identify mechanisms

Maybe a combination of: Plausible RSh levels (segregated

RSh = 0.10) Ecological effects Multigenerational accumulation of

adverse impacts Note that analysis is not for single

generation but for a period of 20 years (4 to 6 generations).

For Consideration

If: Impact from segregated or integrated is

the same, Loss of fitness Araki and others found is

universal, Ph would be the same regardless, and Hatchery program is for harvest;

Should you choose integrated?

Integrated Harvest Programs

Pros Maintains genetic

similarity to wild population

Mimics wild run timing

Anglers love them

Cons Reduces fitness in one

generation Difficult to meet goals

consistently More effort required

to collect brood Requires mining of

wild population

A Hypothesis to Explore

Naturally spawning integrated fish appear to produce more offspring than segregated

Could lead to more F1s, F2s to interbreed with wild population

Might lead to more alteration of the genetic composition of wild population

Fishery benefits could be maintained by managing run timing of segregated broodstock

Might be better off with segregated programs

Questions ?