Seasonal habitat shifts and purse seine dependence of mene maculata in the Taiwan strait: Early indicators of climate driven ecosystem change

Title : Seasonal habitat shifts and purse seine dependence of mene maculata in the Taiwan strait: Early indicators of climate driven ecosystem change

Abstract:

The moonfish (Mene maculata), a dominant forage species in the Taiwan Strait, supports Taiwan’s purse-seine fleets, which account for ~99% of national landings. This gear-specific reliance makes purse-seine catch trends a valuable lens for detecting ecological change. Using Vessel Data Recorder (VDR) data (2013–2023), we analyzed gear-specific catch-per-unit-effort (CPUE) alongside habitat models to investigate seasonal distributional shifts of M. maculata. CPUE was standardized and modeled against environmental variables like sea surface temperature (SST), salinity (SSS), chlorophyll-a (SSC), sea surface height (SSH), and mixed-layer depth (MLD) using Generalized Additive Models (GAMs). Results revealed distinct seasonal shifts: expanded habitats and elevated CPUE in spring and winter contrasted with fragmented habitats in summer under warm, stratified waters, while autumn exhibited transitional redistribution. While Northeast and Southwest Monsoon regimes shaped background ocean variability, finer-scale seasonal drivers particularly SSH, MLD, and SSC emerged as the strongest correlates of CPUE. Habitat centroids shifted southeastward over the decade, consistent with declining purse-seine CPUE and reduced habitat suitability. These patterns parallel recent studies from southwestern Taiwan that document monsoon-driven changes in small pelagic distributions and highlight climate-linked stress on coastal fisheries. Our findings reinforce purse-seine CPUE as a practical early-warning signal of climate stress, given the fleet’s dominance and sensitivity to environmental change. Integrating gear-specific catch data with seasonally resolved habitat models offers a scalable framework for anticipating regime shifts. Embedding such approaches into adaptive, climate-resilient management will be critical to sustain Taiwan Strait fisheries under accelerating ocean change.

Biography:

Ipsita Biswas have worked as an Assistant Professor and Scientist at Dr Rajendra prasad Central Agricultural University in India, gaining over 7.5 years of experience in guiding students, conducting research and promoting sustainable aquaculture and fisheries management practices. Currently, I am pursuing my PhD at National Taiwan Ocean University, Taiwan, focusing on fish stock assessment, conservation biology and bio-economic modeling to address sustainability challenges under climate change. I have published six peer-reviewed journal articles, four popular articles and technical bulletins, one book chapter, and two technical reports. My work has been recognized with the AFS Kanazawa Fellowship, the Young Scientist Award and multiple Best Presentation Awards.