Biro Peter A, Abrahams Mark V, Post John R, Parkinson Eric A
Department of Zoology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
Proc Biol Sci. 2004 Nov 7;271(1554):2233-7. doi: 10.1098/rspb.2004.2861.
Domesticated (farm) salmonid fishes display an increased willingness to accept risk while foraging, and achieve high growth rates not observed in nature. Theory predicts that elevated growth rates in domestic salmonids will result in greater risk-taking to access abundant food, but low survival in the presence of predators. In replicated whole-lake experiments, we observed that domestic trout (selected for high growth rates) took greater risks while foraging and grew faster than a wild strain. However, survival consequences for greater growth rates depended upon the predation environment. Domestic trout experienced greater survival when risk was low, but lower survival when risk was high. This suggests that animals with high intrinsic growth rates are selected against in populations with abundant predators, explaining the absence of such phenotypes in nature. This is, to our knowledge, the first large-scale field experiment to directly test this theory and simultaneously quantify the initial invasibility of domestic salmonid strains that escape into the wild from aquaculture operations, and the ecological conditions affecting their survival.
人工养殖（养殖）的鲑科鱼类在觅食时表现出更高的冒险意愿，并实现了自然界中未观察到的高生长率。理论预测，养殖鲑科鱼类的高生长率将导致为获取丰富食物而承担更大风险，但在有捕食者的情况下存活率较低。在重复的全湖实验中，我们观察到（选择高生长率的）养殖鳟鱼在觅食时承担了更大风险，并且比野生品系生长得更快。然而，更高生长率对生存的影响取决于捕食环境。养殖鳟鱼在风险较低时存活率更高，但在风险较高时存活率较低。这表明，在有大量捕食者的种群中，具有高内在生长率的动物会被淘汰，这解释了自然界中不存在此类表型的原因。据我们所知，这是第一个直接检验该理论并同时量化从水产养殖逃逸到野外的养殖鲑科品系的初始入侵性以及影响其生存的生态条件的大规模实地实验。
