Institut de Biologie Intégrative des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada.
Chaire de recherche sur les espèces aquatiques exploitées, Laboratoire des sciences aquatiques, Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Quebec, Canada.
PLoS One. 2018 Jul 12;13(7):e0200599. doi: 10.1371/journal.pone.0200599. eCollection 2018.
Supplementation stocking is a commonly used management tool to sustain exploited fish populations. Possible negative consequences of supplementation on local stocks are a concern for the conservation of wild fish populations. However, the direct impacts of supplementation on life history traits of local populations have rarely been investigated. In addition, intraspecific hybridization between contrasting ecotypes (planktivorous and piscivorous) has been seldom considered in supplementation plans. Here, we combined genetic (genotype-by-sequencing analysis) and life history traits to document the effects of supplementation on maximum length, growth rates, body condition and genetic admixture in stocked populations of two Lake Trout ecotypes from small boreal lakes in Quebec and Ontario, Canada. In both ecotypes, the length of stocked individuals was greater than local individuals and, in planktivorous-stocked populations, most stocked fish exhibited a planktivorous-like growth while 20% of fish exhibited piscivorous-like growth. The body condition index was positively related to the proportion of local genetic background, but this pattern was only observed in stocked planktivorous populations. We conclude that interactions and hybridization between contrasting ecotypes is a risk that could result in deleterious impacts and possible outbreeding depression. We discuss the implications of these findings for supplementation stocking.
补充放养是一种常用的管理工具，用于维持已开发鱼类种群的数量。补充放养对当地种群可能产生的负面影响引起了人们对野生鱼类种群保护的关注。然而，补充放养对当地种群生活史特征的直接影响很少被研究过。此外，在补充放养计划中，很少考虑不同生态型（食浮游生物和食鱼）之间的种内杂交。在这里，我们结合了遗传（基因型测序分析）和生活史特征，记录了补充放养对来自加拿大魁北克省和安大略省小 boreal 湖泊的两种湖鳟两个生态型的最大长度、生长率、身体状况和遗传混合的影响。在这两个生态型中，放养个体的长度都大于当地个体，并且在食浮游生物放养群体中，大多数放养的鱼类表现出类似食浮游生物的生长，而 20%的鱼类表现出类似食鱼的生长。身体状况指数与本地遗传背景的比例呈正相关，但这种模式仅在放养的食浮游生物种群中观察到。我们得出结论，不同生态型之间的相互作用和杂交是一种风险，可能导致有害影响和可能的远交衰退。我们讨论了这些发现对补充放养的意义。
