Effects of Substrate Type and Other Factors on the Growth, Survival, and Cannibalism of Juvenile Homarus Americanus in Mass Rearing Systems1

Abstract

ABSTRACTMass rearing experiments were conducted as part of our effort to develop effective techniques for commercial culture of the American lobster (Homarus americanus) from the post‐larval stage to adult market size. A preliminary study on effects of food dose level in mass rearing systems is described. An experiment was conducted to determine effects of substrate or shelter type on growth, survival, and cannibalism in juveniles. Fourth‐stage larvae were stocked at densities of 210–317/m2in mass rearing tanks with four different substrate types. After 6 months, the mean density of survivors and the mean carapace length for lobsters held in each substrate were: PVC tubes, 22/m2, 14.4 mm; rock, 24/m2, 13.9 mm; oyster shell, 30/m2, 15.0 mm; sand, 6/m2, 17.3 mm. Mortalities in in these tanks were attributed primarily to cannibalism. Based on the survivorship data, oyster shell appears to be the best culture substrate of those considered for reducing cannibalism and assuring high carrying capacity. Growth rates and aggression, as measured by claw loss, were found to be similar in all substrates tested.