Single or Multiple Climate Oscillations? Impacts on the Northwestern Pacific Seabream Fishery

Sandipan Mondal^1,2Arpita Ghosh¹Alakesh Pradhan¹Ipsita Biswas¹Jinn Shing Weng³Ming-An Lee^1*

• ¹Department of Environmental Biology Fisheries Science, National Taiwan Ocean University, Keelung, Taiwan
• ²Center of excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
• ³Coastal and Offshore Resources Research Center of Fisheries Research Institute, Council of Agriculture, Kaohsiung, Taiwan

Understanding species-specific responses to climate variability is crucial for ecosystem-based fisheries management, especially for high-value multispecies fisheries. This study investigates the impact of climatic oscillations on the catch trends of six commercially important seabream species (Acanthopagrus schlegelii, Dentex hypselosomus, Evynnis cardinalis, Pagrus major, Parargyrops edita, and Rhabdosargus sarba) in Taiwanese waters. Using Generalized Additive Models (GAM), the Pacific Decadal Oscillation (PDO) emerged as the most influential predictor for all species, with deviance explained ranging from 24.6% to 42.3%. Cross-spectrum analysis revealed significant low-frequency periodicities (~2.4 years), while wavelet coherence indicated both direct and delayed species-specific responses to PDO. These findings underscore the importance of decadal-scale climate variability in shaping fishery dynamics and highlight the need to consider asynchronous species responses under a common climatic driver. Such insights can inform adaptive fisheries management and contribute to global policy frameworks in the context of climate change.