Steele Craig A, Delomas Thomas A, Campbell Matthew R, Powell John H
Pacific States Marine Fisheries Commission Eagle Fish Genetics Lab Eagle Idaho USA.
Present address: USDA ARS National Cold Water Marine Aquaculture Center Kingston Rhode Island USA.
Ecol Evol. 2022 Apr 25;12(4):e8846. doi: 10.1002/ece3.8846. eCollection 2022 Apr.
Understanding reproductive patterns in endangered species is critical for supporting their recovery efforts. In this study we use a combination of paired-parent and single-parent assignments to examine the reproductive patterns in an endangered population of sockeye salmon () that uses Redfish Lake in central Idaho as a spawning and nursery lake. Recovery efforts include the release of maturing adults into the lake for volitional spawning. The lake is also inhabited by a population of resident . that is genetically indistinguishable, but phenotypically smaller, to the maturing adults released into the lake. The resident population is difficult to sample and the reproductive patterns between the two groups are unknown. We used results of paired- and single-parentage assignments to specifically examine the reproductive patterns of male fish released into the lake under an equal sex ratio and a male-biased sex ratio. Assignment results of offspring leaving the lake indicated a reproductive shift by males under the two scenarios. Males displayed an assortative mating pattern under an equal sex ratio and spawned almost exclusively with the released females. Under a male-biased sex ratio most males shifted to a negative-assortative mating pattern and spawned with smaller females from the resident population. These males were younger and smaller than males that spawned with released females suggesting they were unable to compete with larger males for spawning opportunities with the larger, released females. The results provided insights into the reproductive behavior of this endangered population and has implications for recovery efforts.
了解濒危物种的繁殖模式对于支持它们的恢复工作至关重要。在本研究中，我们结合双亲与单亲基因分型来研究红大马哈鱼濒危种群的繁殖模式，该种群将爱达荷州中部的红鱼湖用作产卵和育幼湖。恢复工作包括将成熟个体放归湖中进行自然产卵。湖中还栖息着一群当地种群，它们在基因上与放归湖中成熟个体难以区分，但表型上更小。当地种群难以采样，两组之间的繁殖模式也未知。我们利用双亲与单亲基因分型的结果，专门研究了在性别比例相等和雄性偏多的性别比例下，放归湖中雄鱼的繁殖模式。离开湖泊的后代基因分型结果表明，在这两种情况下雄性的繁殖模式发生了转变。在性别比例相等的情况下，雄性表现出选型交配模式，几乎只与放归的雌性交配。在雄性偏多的性别比例下，大多数雄性转变为异选型交配模式，与当地种群中较小的雌性交配。这些雄性比与放归雌性交配的雄性更年轻、更小，这表明它们无法与体型更大的雄性竞争，以获得与体型更大的放归雌性交配的机会。这些结果为这个濒危种群的繁殖行为提供了见解，并对恢复工作具有启示意义。
