Growth of juvenile southern rock lobsters, Jasus edwardsii, is influenced by diet and temperature, whilst survival is influenced by diet and tank environment

Abstract

The growth and survival of juvenile (2–15 g) southern rock lobsters ( Jasus edwardsii) were examined under various culture regimes. In Experiment 1, lobsters held at ambient (13–18°C) or 18°C were fed either fresh mussels, a commercial prawn diet or a moist diet. Growth (specific growth rate (SGR)=1.2–1.32% BW day −1), survival (98%) and food conversion ratios (FCR=1.26–1.29) were significantly better ( P<0.05), and the protein component of the diet best utilised (protein productive value (PPV)=18.3–19%) ( P>0.05), when the lobsters were fed mussels. There was a significant interaction ( P<0.05) between diet and temperature. Growth at 18°C was significantly higher ( P<0.05) than at ambient, except when lobsters were fed the prawn diet when there were no significant differences ( P>0.05). The high acceptance and good consumption rate of formulated diets is a positive first step in the development of commercial diets for southern rock lobsters. In Experiment 2, lobsters held at ambient (13–18°C) or 18°C were maintained in tanks containing hides, substrates or neither. Hides increased survival (98%, cf. 60–75%) ( P>0.05), although they did not increase growth ( P>0.05) compared to tanks without hides. The provision of a substrate to aid the lobsters in the moulting process did not prevent cannibalism. Lobsters grew significantly faster ( P<0.05) at 18°C (SGR=1.32% BW day −1) than at ambient (1.21% BW day −1), with the extra growth explained by a significantly higher ( P<0.05) apparent feed intake. Most mortalities were due to cannibalism of soft-shelled lobsters, suggesting that the design and management of systems will be an important component of mass culturing juvenile J. edwardsii.