McPhee Megan V, Barry Patrick D, Habicht Chris, Vulstek Scott C, Russell Joshua R, Smoker William W, Joyce John E, Gharrett Anthony J
College of Fisheries and Ocean Sciences University of Alaska Fairbanks Juneau Alaska USA.
Alaska Fisheries Science Center National Marine Fisheries Service, National Oceanic and Atmospheric Administration Juneau Alaska USA.
Evol Appl. 2024 Feb 7;17(2):e13640. doi: 10.1111/eva.13640. eCollection 2024 Feb.
Evaluating salmon hatchery supplementation programs requires assessing not only program objectives but identifying potential risks to wild populations as well. Such evaluations can be hampered by difficulty in distinguishing between hatchery- and wild-born returning adults. Here, we conducted 3 years (2011-2013) of experimental hatchery supplementation of sockeye salmon in Auke Lake, Juneau, Alaska where a permanent weir allows sampling and genotyping of every returning adult (2008-2019). We identified both hatchery- and wild-born returning adults with parentage assignment, quantified the productivity (adult offspring/spawner) of hatchery spawners relative to that of wild spawners, and compared run timing, age, and size at age between hatchery- and wild-born adults. Hatchery-spawning females produced from approximately six to 50 times more returning adults than did naturally spawning females. Supplementation had no discernable effect on run timing and limited consequences for size at age, but we observed a distinct shift to younger age at maturity in the hatchery-born individuals in all three brood years. The shift appeared to be driven by hatchery-born fish being more likely to emigrate after one, rather than two, years in the lake but the cause is unknown. In cases when spawning or incubation habitat is limiting sockeye salmon production, hatchery supplementation can be effective for enhancing the number of returning adult fish but not without the risk of phenotypic change in the recipient population, which can be an undesired outcome of hatchery supplementation. This study adds to a growing body of evidence suggesting that phenotypic change within a single generation of captive spawning might be widespread in salmon hatchery programs.
评估鲑鱼孵化场补充计划不仅需要评估计划目标，还需要识别对野生种群的潜在风险。区分孵化场出生和野生出生的洄游成年鱼存在困难，这可能会妨碍此类评估。在此，我们于2011年至2013年在阿拉斯加朱诺的奥克湖对红大马哈鱼进行了为期三年的实验性孵化场补充，该湖有一个永久性堰坝，可对每一条洄游成年鱼（2008年至2019年）进行采样和基因分型。我们通过亲权分配识别出孵化场出生和野生出生的洄游成年鱼，量化了孵化场产卵者相对于野生产卵者的生产力（成年后代/产卵者），并比较了孵化场出生和野生出生成年鱼的洄游时间、年龄和年龄时的大小。孵化场产卵的雌性产生的洄游成年鱼比自然产卵的雌性多大约6至50倍。补充对洄游时间没有明显影响，对年龄时的大小影响有限，但我们在所有三个繁殖年份中都观察到孵化场出生的个体成熟年龄明显向更年轻转变。这种转变似乎是由孵化场出生的鱼在湖中生活一年后而不是两年后更有可能洄游所驱动，但原因尚不清楚。在产卵或孵化栖息地限制红大马哈鱼产量的情况下，孵化场补充可以有效增加洄游成年鱼的数量，但接受种群存在表型变化的风险，这可能是孵化场补充的一个不良后果。这项研究增加了越来越多的证据，表明在鲑鱼孵化场计划中，一代圈养繁殖内的表型变化可能很普遍。
