长江口以北海域鳗苗资源补充量的环境驱动因素OA

To identify the key environmental drivers of glass eel(Anguilla japonica)recruitment in the north coast of the Yangtze River Estuary,we developed a generalized additive model(GAM)using fishing log data from 21 se-lected commercial vessels during the licensed fishing seasons(2022-2024)and ten synchronized environmental variables.The results revealed a significant temporal decline in glass eel resources over the three years,with a pro-gressive delay in the timing of peak catches.In the optimal GAM,sea surface salinity,dissolved inorganic phos-phorus(DIP),and dissolved inorganic nitrogen(DIN)were the key environmental factors influencing glass eel re-cruitment,with explanatory contributions of 17.0％,15.1％,and 13.0％,respectively.DIP showed an oscillating rise with rapid(0.13-0.17 mmol·m-3),slow(0.17-0.25 mmol·m-3),and stable(＞0.25 mmol·m-3)pha-ses.DIN exhibited bimodal oscillations,decreasing(5-6 mmol·m-3),increasing(6-18 mmol·m-3),and then sharply declining(18-20 mmol·m-3).Our results indicated that nutrients(DIP and DIN)and sea surface salini-ty are key environmental drivers influencing glass eel recruitment in the north coast of the Yangtze River Estuary.These findings elevate the role of nutrients from ambiguous background factors to critical determinants of recruitment dynamics,offering a novel perspective for understanding fluctuations in glass eel resources.This new perspective provides a crucial theoretical foundation for the scientific management of glass eel resources.