Use of Parentage Analysis to Determine Reproductive Success of Hatchery‐Origin Spring Chinook Salmon Outplanted into Shitike Creek, Oregon

Abstract

Removal of fish passage barriers provides Pacific salmon Oncorhynchus spp. and steelhead O. mykiss the opportunity to recolonize previously accessible habitat, though the time scale of natural recolonization may not be sufficient for management or conservation goals. One strategy for accelerating recolonization is to outplant hatchery‐origin adults into newly restored habitats. In this paper, we describe how genetic parentage analysis was used to determine the reproductive success of adult stream‐type spring Chinook salmon O. tshawytscha taken from two localized hatchery stocks and outplanted into a stream. We defined reproductive success as the production of migratory juveniles. In 2002 and 2003, 83 and 265 adult hatchery salmon, respectively, were outplanted into Shitike Creek, Oregon, a tributary to the Deschutes River. Using 11 microsatellite markers, 799 and 827 migratory juveniles from the two brood years were genotyped and matched back to potential outplanted parents using genetic parentage analyses. Successful spawning of outplant–outplant, outplant–wild, and wild–wild fish occurred in Shitike Creek in both years. Adults outplanted in 2002 showed far fewer matches (18%) to sampled juveniles than those from 2003 (88%). Additionally, only 1% of juveniles had both parents identified as outplants in 2002, compared with almost 61% in 2003. Differences in the number of females outplanted each year appeared to account for the differential productivity. The number of offspring attributed to an individual outplant was variable, ranging from 1 to more than 10. Multiple outplant × outplant matings were identified for each sex as males mated with up to seven females and females mated with up to four males. This study shows that, under the right conditions, outplanted adult hatchery fish taken from localized hatchery stocks can contribute to the overall juvenile production in a natural stream.

Contribution of genetics to ecological restoration

“…; Baumsteiger et al . ) were assessed using parentage analyses and pedigree reconstruction (Blouin ; Jones et al . ).…”

Planning Pacific Salmon and Steelhead Reintroductions Aimed at Long‐Term Viability and Recovery

“…In a reintroduction or supplementation context, transplants often involve surplus hatchery adults. For example, hatcheryorigin spring Chinook Salmon were transplanted to Shitike Creek, Oregon because the habitat was considered underseeded 15 years after dam removal and produced a significant fraction of the juveniles captured the following spring (Baumsteiger et al 2008). Atlantic Salmon that had spent their entire lives in captivity successfully spawned following release into Wilmot Creek, Ontario (Scott et al 2005b).…”

Impacts of stock enhancement strategies on the effective population size of Murray cod, Maccullochella peelii, a threatened Australian fish

“…DNA analyses can be used to identify the hatchery of origin, family, date of birth, survival and growth rates and dispersal patterns of stocked fish recovered from the wild (e.g. Jeong et al 2007;Baumsteiger et al 2008;Rourke et al 2009). This monitoring technique is non-destructive as a small tissue sample (fin clip) only is required and fish can be released after sampling.…”