[A-OS13] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS13-16] Fish specialize their metabolic performance to maximize bioenergetic efficiency in their local environment

★Invited Papers

*郭 晨穎¹、伊藤 進一¹、米田 道夫²、北野 載²、金子 仁³、榎本 めぐみ¹、青野 智哉¹、中村 政裕²、北川 貴士¹、Wegner Nicolas⁴、Dorval Emmanis⁵ (1.東京大学大気海洋研究所、2.国立研究開発法人水産研究・教育機構、3.海洋研究開発機構、4.アメリカ南西漁業科学センター、5.Lynker Technologies　LLC、アメリカ南西漁業科学センター)

キーワード：マサバ、まさば、代謝、酸素消費率、水温、遊泳速度

Species-specific ecological traits in fishes are likely to vary between populations or stocks due to differences in regional oceanic conditions, such as latitudinal temperature. We examined potential intraspecific differences in the swimming performance and metabolism of chub mackerel (Scomber japonicus) from the Northwest and Northeast stocks, which are distributed on opposite sides of the North Pacific at similar latitudes, but where the temperature contrast is large. Swimming bioenergetics and metabolic data of Northwest stock were measured at 14°C, 18°C, and 24°C using variable-speed swim-tunnel respirometers, and then the resulting bioenergetic parameters were compared with previous findings from the Northeast stock. At a given size, the maximum sustainable swimming speed (U_max) of the Northwest stock showed no significant difference compared to the Northeast stock at 18°C and 24°C, but was lower at 14°C. In addition, the oxygen consumption rate (M_O2) of the Northwest stock showed lower mass dependence and different temperature dependence at a given swimming speed than in the Northeast stock. Combined with stock-specific data on growth and experienced temperatures in the wild, these bioenergetic differences indicate that the swimming performance and metabolism of the two stocks are specific to their local environment to maximize bioenergetic efficiency. This study has been already published on Frontiers in Marine Science (doi:10.3389/fmars.2021.613965).