Diminished Reproductive Success of Steelhead from a Hatchery Supplementation Program (Little Sheep Creek, Imnaha Basin, Oregon)
Diminished Reproductive Success of Steelhead from a Hatchery Supplementation Program (Little Sheep Creek, Imnaha Basin, Oregon)
复制标题
DOI：
10.1080/00028487.2011.584489
复制
发表时间：
2011-05-01
影响因子：
1.4
通讯作者：
Moran, Paul
中科院分区：
文献类型：
--
作者：
Berntson, Ewann A.;Carmichael, Richard W.;Moran, Paul
孵化场补充计划旨在提高自然产量和保持目标种群的健康；然而，很难评估这些项目的成功。这些项目成功的关键是孵化鱼的繁殖成功率相对较高。本研究通过创建孵卵和自然产卵的虹鳟系谱，对虹鳟的相对繁殖成功率进行了研究。我们对成年钢头鱼进行了基因分型，这些钢头鱼回到一个堰后被放归上游，在俄勒冈州东部因纳哈河的一条支流小绵羊溪中产卵。这个补充计划的种鱼最初是从返回堰的天然钢头鱼中选择的，在随后的几年里，既有天然的，也有孵卵场的。微卫星分析显示，这些亲鱼在遗传上与自然种群相似。我们还对来自堰上游多个地点的成年虹鳟鱼进行了基因分型，并确定了在不同生活史阶段收集的后代的亲代，包括随后几年返回的成年虹鳟鱼。在幼鱼和成鱼生命阶段取样的后代分析表明，孵化场来源的鱼的RRS是其自然来源的同行的30-60%。利用广义线性模型分析与繁殖成功率降低相关的各种因素的重要性，我们发现对RRS影响最大的因素是来源（自然与孵化场）、长度、回归日期和同性竞争者的数量。亲生父母受到同性竞争者的负面影响较小。幼鱼的生存差异以及后代和/或产卵的成年鲑鱼的行为差异都可能导致孵化场饲养的鲑鱼的适应性下降，尽管还不能确定这些影响在多大程度上是持久的、可遗传的，而不是与孵化场饲养和放生策略相关的环境影响。
Hatchery supplementation programs are designed to enhance natural production and maintain the fitness of the target population; however, it can be difficult to evaluate the success of these programs. Key to the success of such programs is a relatively high reproductive success of hatchery fish. This study investigated the relative reproductive success (RRS) of steelhead Oncorhynchus mykiss (anadromous rainbow trout) by creating pedigrees for hatchery and natural spawning steelhead. We genotyped adult steelhead that returned to a weir and were released upstream to spawn in Little Sheep Creek, a tributary to the Imnaha River in eastern Oregon. The broodstock for this supplementation program were originally chosen from natural-origin steelhead returning to the weir and in subsequent years consisted of both natural-and hatchery-origin individuals. Microsatellite analyses showed the broodstock to be genetically similar to the natural population across years. We also genotyped adult resident rainbow trout from multiple locations upstream of the weir and determined the parentage of progeny collected at various life history stages, including returning adults in subsequent years. Analysis of progeny sampled at both the juvenile and adult life stages suggested that the RRS of hatchery-origin fish was 30-60% that of their natural-origin counterparts. Using generalized linear models to address the importance of various factors associated with reduced reproductive success, we found that the greatest effects on RRS were origin (natural versus hatchery), length, return date, and the number of same-sex competitors. Natural parents were less negatively affected by same-sex competitors. Differential survival of juveniles and the behavior of offspring and/or spawning adults may all contribute to diminished fitness in hatchery-reared salmon, although it could not be determined to what extent these effects were of a persistent, heritable nature as distinct from an environmental effect associated with hatchery rearing and release strategies.