Biochemical composition as a growth predictor in male west-coast rock lobster (Jasus lalandii)

The biochemical composition of the hepatopancreas and abdominal muscle tissue of adult male Jasus lalandii in two size classes was examined on a monthly and moult-cycle basis over four years to determine the accumulation and utilization of the major reserves in these tissues. The possibility of using this information to predict moult increment, defined as the increase in carapace length, was examined. Two study areas were selected to provide contrasting information on high and low growth rates, and the annual moult increments in these areas were determined from tag-and-recapture studies. The biochemical composition of abdominal muscle did not meet the prerequisites for a predictive index of growth. Hepatopancreas moisture content (lowest values measured during accumulation of reserves) showed a negative correlation with growth increment. Peak lipid content (as both percentage and absolute values) showed a positive correlation with measured moult increment. The relationship between percentage of lipid (both size classes combined) and moult increment was highly significant. Notwithstanding the limitations introduced by the small number of high-growth data points in this study, it appears that hepatopancreas lipid content can be used as a simple and robust predictive indicator of growth in adult male J. lalandii.