Nusslé Sébastien, Bornand Christophe N, Wedekind Claus
Department of Ecology and Evolution, University of Lausanne Lausanne, Switzerland.
Evol Appl. 2009 May;2(2):200-8. doi: 10.1111/j.1752-4571.2008.00054.x. Epub 2008 Dec 17.
Size-selective fishing, environmental changes and reproductive strategies are expected to affect life-history traits such as the individual growth rate. The relative contribution of these factors is not clear, particularly whether size-selective fishing can have a substantial impact on the genetics and hence on the evolution of individual growth rates in wild populations. We analysed a 25-year monitoring survey of an isolated population of the Alpine whitefish Coregonus palaea. We determined the selection differentials on growth rate, the actual change of growth rate over time and indicators of reproductive strategies that may potentially change over time. The selection differential can be reliably estimated in our study population because almost all the fish are harvested within their first years of life, i.e. few fish escape fishing mortality. We found a marked decline in average adult growth rate over the 25 years and a significant selection differential for adult growth, but no evidence for any linear change in reproductive strategies over time. Assuming that the heritability of growth in this whitefish corresponds to what was found in other salmonids, about a third of the observed decline in growth rate would be linked to fishery-induced evolution. Size-selective fishing seems to affect substantially the genetics of individual growth in our study population.
大小选择性捕捞、环境变化和繁殖策略预计会影响个体生长率等生活史特征。这些因素的相对贡献尚不清楚，尤其是大小选择性捕捞是否会对野生种群的遗传学产生重大影响，进而影响个体生长率的进化。我们分析了对高山白鲑（Coregonus palaea）一个孤立种群进行的为期25年的监测调查。我们确定了对生长率的选择差异、生长率随时间的实际变化以及可能随时间变化的繁殖策略指标。在我们的研究种群中可以可靠地估计选择差异，因为几乎所有的鱼在其生命的头几年内就被捕捞，即很少有鱼逃脱捕捞死亡。我们发现，在这25年中，成年鱼的平均生长率显著下降，并且成年生长存在显著的选择差异，但没有证据表明繁殖策略随时间有任何线性变化。假设这种白鲑生长的遗传力与其他鲑科鱼类的情况相符，那么观察到的生长率下降中约有三分之一将与渔业诱导的进化有关。大小选择性捕捞似乎对我们研究种群中个体生长的遗传学有重大影响。
