Effect of Starvation on the Temperature Preference of Young Horse Mackerel, Trachurus japonicus

Abstract

Effect of starvation on the temperature preference of young horse mackerel Trachurus japonicus was investigated with a vertical temperature gradient. The fish, which had been previously fed to satiation at 25°C, were starved for 56 days. Condition factor of the starved fish decreased from 1.85 to 1.43 during the experiment. The preferred temperatures of the fed and starved groups were 25.3 and 23.0 °C, respectively; no change in preferred temperature was observed during starvation. The thermoregulatoly behavior of starved fish may be effective in sparing the endogenous energy reserves, because the metabolic rate is conceivably less at lower sparing temperatures.