[A-OS09] 海洋混合学：物質循環・気候・生態系の維持と長周期変動の解明

[AOS09-11] Influence of tide on the growth and migration of walleye pollock (Gadus chalcogrammus) in the Oyashio region

*伊藤 進一¹、王 子健¹、西川 はつみ³、三寺 史夫³、石野 光弘² (1.東京大学大気海洋研究所、2.水産研究・教育機構、3.北海道大学)

キーワード：海洋生態系モデル、魚類成長－回遊モデル、スケトウダラ

A bioenergetics model of walleye pollock (Gadus chalcogrammus) coupled with a lower trophic level nutrient-phytoplankton-zooplankton model was developed to investigate environmental effects on the pollock growth in the Oyashio region. The bioenegertics model was coupled to was coupled to a migration model of pollock based on the environments calculated by an ocean general circulation model (CCSR (Center for Climate System Research) Ocean Component Model: COCO) coupled to a simple nutrient cycle model. In the growth-migration model, two physical environment conditions (with and without tidal forcing) were applied to investigate the tidal effects on the growth and migration of pollock. With tidal effect, warm water supply through the Tsugaru Strait to the southwestern coast of Hokkaido increased and a strong temperature front was formed along the southwestern coast of Hokkaido. Coastal current associated with the temperature front advected the pollock larvae to the Cape Erimo and pollock successfully settled to the bottom layer. Comparing the result without tidal forcing, tide potentially provide optimal temperature condition for growth and higher possibility to settle near coast. On the contrary, tide potentially provide lower nutrient supply with increasing nutrient poor water through the Tsugaru Strait. Therefore, the pollock growth itself did not change between with and without tidal forcing.