Long-term dynamics of fish communities: A 16-years study in the Yeosu Coast, Korea

The Yeosu Coast, a region of critical ecological and economic importance on the Korean Peninsula, has experienced significant changes in fish community dynamics over recent decades. This study provides a comprehensive analysis of daily set-net catch data collected from 2008 to 2023 (excluding 2017) to investigate long-term shifts in species composition and community structure. The findings indicate a dominance of warm-water species, reflecting the region’s temperate to subtropical marine environment. During the study period, the total catch amounted to 3,501.9 tonnes, with the highest annual catch recorded in 2010 and the lowest in 2016. Species composition changes were strongly correlated with sea surface temperature, identified as the primary environmental driver of these dynamics. The dominant species, Scomberomorus niphonius (Cuvier, 1832) and Engraulis japonicus (Temminck & Schlegel, 1846), together accounted for 77.4% of the total biomass. Biodiversity trends, measured using the Shannon–Weaver diversity index, revealed a marked decline in 2015 compared to 2008, highlighting significant alterations in community structure. Furthermore, the study emphasizes the compounded threats of climate change and the increasing prevalence of jellyfish blooms, which pose serious challenges to fishery productivity and biodiversity. These results underscore the urgent need for targeted management strategies and sustained monitoring to ensure the long-term sustainability of fisheries in this region amidst ongoing environmental changes.