Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
Institute for Environmental Protection and Research (ISPRA), Livorno, Italy.
J Anim Ecol. 2019 Sep;88(9):1343-1354. doi: 10.1111/1365-2656.13032. Epub 2019 Jun 13.
The role of sexual selection in the context of harvest-induced evolution is poorly understood. However, elevated and trait-selective harvesting of wild populations may change sexually selected traits, which in turn can affect mate choice and reproduction. We experimentally evaluated the potential for fisheries-induced evolution of mating behaviour and reproductive allocation in fish. We used an experimental system of zebrafish (Danio rerio) lines exposed to large, small or random (i.e. control) size-selective mortality. The large-harvested line represented a treatment simulating the typical case in fisheries where the largest individuals are preferentially harvested. We used a full factorial design of spawning trials with size-matched individuals to control for the systematic impact of body size during reproduction, thereby singling out possible changes in mating behaviour and reproductive allocation. Both small size-selective mortality and large size-selective mortality left a legacy on male mating behaviour by elevating intersexual aggression. However, there was no evidence for line-assortative reproductive allocation. Females of all lines preferentially allocated eggs to the generally less aggressive males of the random-harvested control line. Females of the large-harvested line showed enhanced reproductive performance, and males of the large-harvested line had the highest egg fertilization rate among all males. These findings can be explained as an evolutionary adaptation by which individuals of the large-harvested line display an enhanced reproductive performance early in life to offset the increased probability of adult mortality due to harvest. Our results suggest that the large-harvested line evolved behaviourally mediated reproductive adaptations that could increase the rate of recovery when populations adapted to high fishing pressure come into secondary contact with other populations.
性选择在捕捞诱导进化中的作用还知之甚少。然而，对野生种群的大量和特征选择性捕捞可能会改变性选择特征，进而影响配偶选择和繁殖。我们通过鱼类交配行为和生殖分配的渔业诱导进化的实验评估，来评估潜在的进化。我们使用了一个斑马鱼（Danio rerio）系的实验系统，这些鱼系暴露在大、小或随机（即对照）大小选择性死亡率下。大型捕捞线代表了一种模拟渔业中最常见情况的处理，即最大个体被优先捕捞。我们使用大小匹配个体的产卵试验完全因子设计来控制繁殖过程中体型的系统影响，从而单独确定交配行为和生殖分配可能发生的变化。小尺寸选择性死亡率和大尺寸选择性死亡率都通过提高两性间的攻击性，对雄性交配行为产生了遗传影响。然而，没有证据表明生殖分配具有线相关性。所有系的雌性都优先将卵分配给随机捕捞对照系中通常攻击性较弱的雄性。大型捕捞线的雌性表现出增强的生殖性能，而大型捕捞线的雄性的卵受精率在所有雄性中最高。这些发现可以解释为一种进化适应，即大型捕捞线的个体在生命早期表现出增强的生殖性能，以抵消因捕捞而增加的成年死亡率的可能性。我们的研究结果表明，大型捕捞线进化出了行为介导的生殖适应性，当适应高捕捞压力的种群与其他种群再次接触时，可能会增加种群恢复的速度。
