Christie Mark R, Ford Michael J, Blouin Michael S
Department of Integrative Biology, Oregon State University Corvallis, OR, USA ; Department of Biological Sciences and Department of Forestry and Natural Resources, Purdue University West Lafayette, IN, USA.
Conservation Biology Division, National Marine Fisheries Service, Northwest Fisheries Science Center Seattle, WA, USA.
Evol Appl. 2014 Sep;7(8):883-96. doi: 10.1111/eva.12183. Epub 2014 Jul 9.
Large numbers of hatchery salmon spawn in wild populations each year. Hatchery fish with multiple generations of hatchery ancestry often have heritably lower reproductive success than wild fish and may reduce the fitness of an entire population. Whether this reduced fitness also occurs for hatchery fish created with local- and predominantly wild-origin parents remains controversial. Here, we review recent studies on the reproductive success of such 'early-generation' hatchery fish that spawn in the wild. Combining 51 estimates from six studies on four salmon species, we found that (i) early-generation hatchery fish averaged only half the reproductive success of their wild-origin counterparts when spawning in the wild, (ii) the reduction in reproductive success was more severe for males than for females, and (iii) all species showed reduced fitness due to hatchery rearing. We review commonalities among studies that point to possible mechanisms (e.g., environmental versus genetic effects). Furthermore, we illustrate that sample sizes typical of these studies result in low statistical power to detect fitness differences unless the differences are substantial. This review demonstrates that reduced fitness of early-generation hatchery fish may be a general phenomenon. Future research should focus on determining the causes of those fitness reductions and whether they lead to long-term reductions in the fitness of wild populations.
每年都有大量孵化场养殖的鲑鱼在野生种群中产卵。具有多代孵化场血统的养殖鱼通常在遗传上的繁殖成功率低于野生鱼，并且可能会降低整个种群的适应性。对于由本地且主要是野生亲本培育的养殖鱼而言，这种适应性降低的情况是否也会发生，仍存在争议。在此，我们回顾了近期关于此类在野生环境中产卵的“初代”养殖鱼繁殖成功率的研究。综合四项鲑鱼物种的六项研究中的51项估计数据，我们发现：（i）初代养殖鱼在野生环境中产卵时，其繁殖成功率平均仅为野生亲本同类的一半；（ii）雄性养殖鱼繁殖成功率的降低比雌性更为严重；（iii）所有物种均因孵化场养殖而出现适应性降低的情况。我们回顾了各项研究中的共性，这些共性指出了可能的机制（例如，环境效应与遗传效应）。此外，我们还表明，这些研究中典型的样本量导致统计效力较低，难以检测到适应性差异，除非差异很大。本综述表明，初代养殖鱼适应性降低可能是一种普遍现象。未来的研究应着重确定这些适应性降低的原因，以及它们是否会导致野生种群适应性的长期降低。
