Breeding Success of Wild and First‐Generation Hatchery Female Spring Chinook Salmon Spawning in an Artificial Stream

Abstract

First-generation hatchery and wild spring Chinook salmon Oncorhynchus tshawytscha from the upper Yakima River, Washington, were placed into an artificial stream and allowed to spawn. Seven independent test groups were placed into the stream from 2001 through 2005. No differences were detected in the egg deposition rates of wild and hatchery females. Pedigree assignments based on microsatellite DNA, however, showed that the eggs deposited by wild females survived to the fry stage at a 5.6% higher rate than those spawned by hatchery females. Subtle differences between hatchery and wild females in redd abandonment, egg burial, and redd location choice may have been responsible for the difference observed. Body size did not affect the ability of females to spawn or the survival of their deposited eggs. How long a female lived was positively related to her breeding success, but female origin did not affect longevity. The density of females spawning in portions of the stream affected both egg deposition and egg-to-fry survival. No difference, however, was found in the overall distribution patterns of the two types of females. Other studies that have examined the effects of a single generation of hatchery culture on upper Yakima River Chinook salmon have disclosed similar low-level effects on adult and juvenile traits. The cumulative effect of such differences will need to be considered when hatcheries are used to restore depressed populations of Chinook

Breeding success of four male life history types of spring Chinook Salmon spawning in an artificial stream

“…Fish selection and introduction into the artificial stream followed the protocols previously described in Schroder et al (2008Schroder et al ( , 2010. Briefly, beginning in early September, fish were examined weekly to determine their maturation status.…”

“…Water velocity (0.1-2.0 m/s), discharge (0.37 m 3 /s) and depth (mean 0.4 m) mimicked conditions that spawning Chinook salmon typically prefer (Bjornn and Reiser 1991;Healey 1991). A 2.1-m high wall of camouflage netting was installed on both banks with observation openings at eye level every m along its length (Schroder et al 2008).…”

“…Methods used to perform the pedigree analyses have been previously described in Schroder et al (2008Schroder et al ( , 2010. For test groups 2001A and 2001B, genomic DNA was extracted from the fry and adult samples by digesting their tissues in a 5% chelex solution containing 0.4 mg proteinase K. Following digestion the samples were heated to denature proteins and DNA extracts were stored at 5°C until all analyses were completed.…”

“…In two previous papers we compared the breeding success of first-generation hatchery and wild female (Schroder et al 2008) and male spring Chinook salmon spawning in an artificial stream. Because of the ubiquitous presence of precocious males and jacks in the upper Yakima River, and the desire to mimic natural social conditions, we included precocious males and jacks along with large anadromous males and females in seven test groups placed into the artificial stream.…”

Analysis of gene origin in the first adult returns to the Cultus sockeye salmon captive breeding program

“…Captive individuals from the Cultus program were released into an extant population of recent coancestry so that inbreeding may have occurred whether hatchery-produced individuals bred with each other or with wild-born individuals. Additionally, environmental or genetic factors other than inbreeding that reduce the reproductive capacity of hatchery-born animals in the wild (Araki et al 2007a;Schroder et al 2008) may impact 'hybrid' progeny resulting from the mating of hatcheryand wild-born parents, leading to a further decline in population productivity.…”