Seasonal atmospheric forcing and shelf-scale oceanographic variability shapes demersal trawl fisheries in the Visayan Sea, Philippines

Tropical coastal shelf ecosystems are shaped by strong seasonal atmospheric forcing and intense human exploitation. However, the links between physical oceanographic variability and fisheries dynamics remain poorly understood, particularly in data-limited regions. In the Philippine seas, seasonal changes in wind forcing and upper-ocean conditions influence stratification, mixing, and productivity, with potential consequences for demersal fish communities exploited by bottom trawl fisheries. This study investigates how seasonal oceanographic variability relates to patterns in catch and catch per unit effort (CPUE) of an otter trawl fishery in the Visayan Sea, central Philippines. Fisheries-dependent observations, including depth-stratified CPUE and species composition are integrated with environmental parameters derived from atmospheric reanalysis and gridded ocean datasets. Seasonal atmospheric forcing is characterized using surface wind fields, while ocean surface and upper-layer conditions are described using sea surface temperature (SST), temperature anomalies, and productivity proxies. To match the temporal resolution of the fisheries data, analyses focus on contrasts between the wet and dry seasons. Seasonal differences in catch patterns and community composition are examined in relation to environmental variability. Life-history traits are used as an interpretative framework to explore whether seasonal environmental regimes and trawling pressure may differentially affect species with contrasting growth and reproductive strategies. By combining atmospheric forcing, shelf-scale oceanographic processes, and fisheries obervations, this study highlights the role of physical-biological coupling in mediating the impacts of climate variability and human activities on demersal fisheries. The findings aim to contribute to a process-based understanding of coastal fisheries dynamics in tropical shelf systems and demonstrate the value of interdisciplinary approaches for studying coupled ocean-human systems.