Pelagic and demersal fish population rebuilding in response to fisheries-induced evolution in exploited China Seas

Abstract

Marine ecosystems are undergoing life-history adaptations with impacts on productivity, resilience, and economic value due to Fisheries-Induced Evolution (FIE). Long-term and often intense selective commercial harvesting has led to truncations in population structure and evolutionary changes in key life-history traits. However, the consequences for different functional groups have rarely been evaluated, especially in the context of rebuilding depleted marine stocks. This study uses an individual-based eco-genetic modeling approach to investigate the effects of FIE during shifts in fishing intensity. We focus on functional groups of three types of pelagic fish and three types of demersal fish with different life histories in the China Seas, proposing and evaluating two types of evolving trait response indicators to FIE, and assessing the influence of fishing intensity during the population rebuilding phase. Our results indicate that FIE has a more pronounced impact on biomass recovery in demersal fishes compared to pelagic fishes. The recovery time ranges from 10 to 40 years and strongly correlates with length at 50% vulnerability ($L_{50}$). Reductions in fishing intensity facilitate biomass recovery, particularly in demersal fishes. In conclusion, our study suggests that adopting a management approach tailored to the needs of distinct functional groups is highly beneficial for promoting the efficient recovery of declining demersal fisheries. This understanding is crucial for developing effective fishery management strategies that integrate the evolutionary responses of different functional groups.