Is individual variation in metabolic rate related to growth of spiny lobster in culture and what is the influence of social interaction?

Research with a variety of aquatic ectotherms suggests that variation in individual metabolic rate (i.e., metabolic phenotype) can be a factor that influences the behaviour and growth of individuals. Slow growth, growth disparity and growth depensation have been reported as major drawbacks to spiny lobster production which is thought to be associated with agonistic behaviour of dominant individuals controlling a disproportional share of food resources. Our study examined the relationship between individual variation of metabolic phenotypes (standard, routine and active metabolic rates and aerobic scope), and growth performance of juvenile spiny lobster, Sagmariasus verreauxi (5.99 +/- 0.46 g) that were reared either individually (n = 20) or communally as a group of 20 for 90 days. Growth performance and feed intake were significantly higher in communal rearing demonstrating that social interaction is important for promoting growth of spiny lobsters. There was a positive relationship between standard metabolic rate, routine metabolic rate and growth in individually reared lobsters indicating a direct link between metabolic phenotype and growth of lobsters in the absence of social interaction. There was no relationship between metabolic phenotype and growth in communal rearing suggesting that social interactions outweigh the direct link between metabolic rate and lobster growth. The results demonstrate for the first time that growth performance of spiny lobsters can be linked with individual variation in metabolic status however social behaviour plays a more dominant role in determining growth of this naturally gregarious species.