Inbreeding and inbreeding depression in hatchery steelhead K Naish, TR Seamons, M Dauer, T Quinn, L Hauser University of Washington School of Aquatic and Fishery Sciences K Naish, TR Seamons, M Dauer, T Quinn, L Hauser University of Washington School of Aquatic and Fishery Sciences

Acknowledgements Faculty Paul Bentzen, Dalhousie U Tom Quinn, UW Lorenz Hauser, UW Kerry Naish, UW Jeff Hard, NMFS Hatchery Crew George Britter, WDFW Rob Allan, WDFW Dave Shores, WDFW Kevin Flowers, WDFW Jenny Allan Merle Hash Larry Sienko Max Burleson Lab and Field Lyndsay Newton Duy Mai Will Atlas Many others... Funding Weyerhaeuser H. Mason Keeler Endowment Hatchery Science Reform Group National Science Foundation (DEB ) Bonneville Power Administration ( ) Former Students Greg Mackey Jennifer McLean Michael Dauer

Negative genetic risks of hatchery supplementation On hatchery fish –Loss of genetic diversity Inbreeding –Domestication On wild fish –Loss of genetic diversity –Introgression Outbreeding depression Loss of population structure Naish et al Advances in Marine Biology

Spawned and killed at the hatchery To Willapa River (0.1 km) Highway 6 Spawned Released as smolts Return to hatchery

WA State hatchery Provides fish for recreational fisheries No tribal or in- stream commercial harvest Also rear –Chinook –Coho

Hatchery population is losing genetic diversity Spawned a fraction of the population –Larger Assortatively spawned large fish –Earlier Earlier spawned fish had more surviving offspring Variance in reproductive success is high –Higher in males –Low effective number of breeders McLean et al Cons. Biology, McLean et al Cons. Genetics

Data and approach Pedigree – Inferred from genetic data Inbreeding? Inbreeding depression? –Change in traits correlated with fitness Fork length, body weight, day of return, gonad mass, fecundity, egg size

Study design: hatchery fish Molecular based pedigree 6602 hatchery fish over 14 return years 5738 (2952 males and 2546 females) were included in the pedigree (86.9% of all clipped fish) Initiatio n year Return year F 0 returnF 1 returnF 2 returnF 3 return Freshwater phase Marine phase

Identifying inbred individuals in a pedigree F - “the probability that both alleles at a locus are identical by descent” F ranges from 0 to B AC D E X “Traditional” pedigree “Inbreeding” pedigree

Inbreeding in the hatchery Delta F RY N return % Inbred Full sibHalf sibHalf second cousins Half first cousins First cousins ^^^^^ Increasingly inbred

Complexity in pedigrees A greater range of inbreeding classes can be detected with deeper pedigrees Lowest F F F F F F

Amount of inbreeding not unexpected given Ne Gen N return Sex N spawn kiki σ2iσ2i N e_sex N e­_var N e_both F0341F M F1444F M F21577F M Avg Avg. no. offspring by sex Variance in reproductive success by sex ^ N e based on variance in sex ratio and reproductive success v Expected F t in F3 = Actual F t in F3 = SD = ^

Breeding protocol –5 x 5 (+-) in one bucket –Average of 53 females 58 males –1 x 1 in one bucket –Average of 85 females 85 males

Total Spawned (males + females) Fraction of population spawned is low Adults (count) Year

Ways to improve Increase fraction of population spawned Decrease variance in family size –2003 unintentionally transferred or killed all but one spawning date Decrease variance in male reproductive success relative to female reproductive success –Water harden before combining More labor and space intensive

Inbreeding depression in O.mykiss In culture, close inbreeding (F=0.25) leads to a rapid decline in fitness (Pante et al. 1993) Results repeated in a controlled release in Alaska (Thrower and Hard, 2009) Decreased marine survival rates in inbred smolts released from two captive broodstocks.