Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä 40014, Finland.
Department of Biology, Dalhousie University, Halifax NS B3H 4R2, Canada.
Proc Biol Sci. 2022 Aug 31;289(1981):20221172. doi: 10.1098/rspb.2022.1172.
Can the advantage of risk-managing life-history strategies become a disadvantage under human-induced evolution? Organisms have adapted to the variability and uncertainty of environmental conditions with a vast diversity of life-history strategies. One such evolved strategy is multiple-batch spawning, a spawning strategy common to long-lived fishes that 'hedge their bets' by distributing the risk to their offspring on a temporal and spatial scale. The fitness benefits of this spawning strategy increase with female body size, the very trait that size-selective fishing targets. By applying an empirically and theoretically motivated eco-evolutionary mechanistic model that was parameterized for Atlantic cod (), we explored how fishing intensity may alter the life-history traits and fitness of fishes that are multiple-batch spawners. Our main findings are twofold; first, the risk-spreading strategy of multiple-batch spawning is not effective against fisheries selection, because the fisheries selection favours smaller fish with a lower risk-spreading effect; and second, the ecological recovery in population size does not secure evolutionary recovery in the population size structure. The beneficial risk-spreading mechanism of the batch spawning strategy highlights the importance of recovery in the size structure of overfished stocks, from which a full recovery in the population size can follow.
在人为引发的进化下，管理生活史策略的优势是否会变成劣势？生物已经通过多种多样的生活史策略适应了环境条件的可变性和不确定性。其中一种进化策略是分批产卵，这是一种常见于长寿鱼类的产卵策略，它们通过在时间和空间上分散后代的风险来“分散赌注”。这种产卵策略的适应性优势随着雌性个体的体型增大而增加，而正是这种体型特征成为了大小选择性捕捞的目标。我们应用了一个具有经验和理论基础的生态进化机制模型，该模型针对大西洋鳕鱼（）进行了参数化，以探索捕捞强度如何改变分批产卵鱼类的生活史特征和适应性。我们的主要发现有两点：第一，分批产卵的风险分散策略不能有效抵御渔业选择，因为渔业选择偏爱体型较小、风险分散效果较低的鱼类；第二，种群大小的生态恢复并不能确保种群大小结构的进化恢复。分批产卵策略的有益风险分散机制强调了恢复过度捕捞种群大小结构的重要性，因为只有这样才能使种群数量得到全面恢复。
