Effect of incubation and rearing temperature on locomotor ability in barramundi, Lates calcarifer Bloch, 1790

Abstract

Temperature profoundly influences virtually all aspects of fish biology. Barramundi, Lates calcarifer Bloch, 1790, is a catadromous fish that undergoes several migrations in its life cycle, necessitating locomotion under various thermal conditions. The present study examined the effects of varying thermal regimes on performance in juvenile L. calcarifer by determining the effects of rearing and ambient temperature on burst (Umax) and sustained (Ucrit) swimming ability. Fish were incubated at three set temperatures, 26°C (cool), 29°C (control) and 31°C (warm), from egg fertilisation until first feeding before some of the larvae were allocated to different temperatures to differentiate the effects of incubation temperature v. rearing temperature on subsequent swimming performance. Individuals incubated and reared at the cool (26°C) temperature showed significantly faster burst speeds at the 26°C test temperature than fish from any other treatment group. This indicates the ability of L. calcarifer to thermally acclimate burst swimming. However, there was no evidence that incubation temperature (as opposed to rearing temperature) affected burst or sustained swimming ability. Swimming ability was significantly affected by the test temperature, with the Umax of fish highest at the 29°C test temperature. Lower test temperatures depressed both burst and sustained swimming ability. Juvenile L. calcarifer can acclimate Umax, but swimming ability was unaffected by incubation thermal history.