Correlation between oceanic environmental fluctuation and bluefin tuna behavior in the aquaculture pen

Abstract

The visceral temperature of three Pacific bluefin tuna cultured in the aquaculture pen were analyzed to estimate basal physiological condition. The data logger with depth and temperature sensor was surgically implanted in the abdominal cavity of the fish. The value of visceral temperature (T) was divided into 3 factors, which were the ambient water temperature (W), temperature fluctuation induce by swimming activity (S), and temperature fluctuation by food digestion and assimilation (F). In our analysis, S and F were estimated as follows; S = 1.3±0.33℃, F = 0.8±0.85℃. The elapsed times from digestion to assimilation were 38 - 41 hour.