Identifying drivers of change during the recent two decades in the Visayan Sea using a trophic modeling approach

The Visayan Sea is one of the major traditional fishing grounds in Philippines and likewise considered as a top contributor to country’s overall fisheries production. However, surveys conducted over past couple decades have documented changes abundance composition catches stocks toward an increasing dominance invertebrates low trophic levels fish families. Assessments commercially-important pelagic demersal were used estimate population parameters that already exceed sustainable reference limits. These assessments point exclusively likely cause observed status trends, but they fail incorporate potential influence interactions variable environmental conditions despite nationally-legislated mandate apply ecosystem approach assessing managing fisheries. Thus, model (Ecopath with Ecosim) was constructed investigate role extent fishery, interactions, changing drivers stock dynamics. results suggest its corresponding effects are invertebrate biomass two decades, while trends provide explanations for patterns cannot be explained by alone. Incorporating sea surface temperature variations primary productivity anomalies produced best-fitting models most catch trends. small pelagics (i.e., sardines mackerels) found particularly affected rainfall, fishes also show sensitivity chlorophyll-a concentrations. further showed significant correlation Pacific Decadal Oscillation (PDO), which suggests bottom-up controls system may long-term regional climatic changes. findings validate applicability necessity modeling exploited marine ecosystems complement analyses from typically single-species assessments, especially face variability projected climate change scenarios.