Growth at molt of sub-adult scalloped spiny lobster Panulirus homarus reared in tanks

Abstract

Grow-out of lobster performed in a tank culture system offers several advantages over floating sea cage culture, particularly in the control of environmental factors. However, the growth of lobster reared in tanks need to be evaluated to determine the rearing period of lobster to achieve market size. Growth in lobster is defined as the change in size through the molting process. Therefore, this study was performed to assess differences in weight and length increment at molt of male and female sub-adult scalloped spiny lobster Panulirus homarus, as well as to determine the annual weight increment of the lobster reared in tanks. Sub-adult lobsters with an initial average weight of 226.18±20.30 g were stocked in twenty 4000-L fiber tanks at 20 lobsters/tank. Each lobster was tagged by a photographic method of the carapace to enable the identification of individual molt, as well as growth increment. Observation of molt and growth of lobster was carried out for 42 days of rearing. Growth observation for 42 days showed that the length increment between male and female lobsters was significantly different. The average length increment of the male was significantly higher (10.00 mm) than those of the female (7.93 mm) (p<0.05). However, the weight increment was not different between the sexes. The average weight increment of males and females was 18.53 g and 20.71 g, respectively (p>0.05). In terms of the annual weight increment, both sexes also had fairly similar growth, achieving 168.38 g.yr-1, on average. This study found that there was increased growth, zero growth, and declined growth at molt in lobster P. homarus.