The effect of temperature on survival, growth, feeding and metabolic activity of the southern rock lobster, Jasus edwardsii
Thomas, CW and Crear, BJ and Hart, PR, The effect of temperature on survival, growth, feeding and metabolic activity of the southern rock lobster, Jasus edwardsii, Aquaculture, 185, (1) pp. 73-84. ISSN 0044-8486 (2000) [Refereed Article]
This study investigated the effect of temperature (18, 20, 22 and 24°C) on growth, feeding and metabolism of post-puerulus lobsters as part of a larger study of the culture potential of farming the southern rock lobster, Jasus edwardsii. There was no significant difference (P > 0.05) in the specific growth rates (SGR) at 18, 20 or 22°C; however growth decreased significantly (P < 0.05) at 24°C. The growth response was described by a quadratic regression (SGR= -0.031T2+ 1.261T - 10.884, r2 = 0.77), which predicted the optimum temperature for growth to be 20.6°C. Lobsters held at 22°C had smaller intermoult periods than lobsters at 18°C; however, a decreased moult increment at 22°C meant that growth rate did not increase at that temperature. The decreased growth at 24°C compared to 22°C was evidenced by a longer intermoult period. Temperature affected survival of lobsters, with survival at 24°C being significantly lower (P < 0.05) than at 18°C. There were no significant differences (P > 0.05) in survival at 18, 20 or 22°C. The response of feed conversion ratio (FCR) to temperature was described by a quadratic regression (FCR=.0.011T2 - 0.434T ± 5.231, r2= 0.995), which suggested that the optimum temperature for feed conversion was 19.3°C. Oxygen consumption rates (M(O)2) increased with increasing temperatures between 18°C and 22°C and declined at 24°C; whilst total ammonia nitrogen (TAN) excretion increased with increasing temperature. The relationships were described by regression equations: M(O)2 = -0.044T2 ± 1.91T - 18.553 (r2 = 1.0); TAN = 0.127T - 1.174 (r2 = 0.91). A temperature of 24°C appears to be above the upper thermal tolerance of juvenile J. edwardsii. Lobsters held at this temperature showed reduced survival (compared to those at 18°C), reduced growth (compared to those at 22°C) and appeared to be suffering from respiratory stress (moult-related mortalities, low Q10 between 22°C and 24°C). Overall, the results indicate that juvenile J. edwardsii can be cultured at 22°C without adversely affecting their growth, survival or feed efficiency with optimal temperature range between 19 and 21°C. (C) 2000 Elsevier Science B.V.