Life Cycle and Natural Mortality Rates of the Blue Spiny Lobster (Panulirus inflatus)

The natural mortality rate (M) is a crucial population parameter, particularly for managing exploited stocks. Empirical methods developed to estimate M generally depend on individual growth and habitat temperature. The gnomonic-stage method, in contrast, allows estimates of M for all life-history stages considered of a species; the challenge is how to derive a single M value for use in further fisheries analyses. In this study, a single M value was derived using the gnomonic method for the blue lobster (Panulirus inflatus) fished off the southern Gulf of California. The estimated M value relied on existing biological data for the exploited phase of the species for which there is only scarce information. Because in the gnomonic method, M relates to fecundity, a sensitivity analysis of yield-per-recruit to different fecundity values was performed. The results have practical implications for ecology and stock assessment of the blue spiny lobster and other fished resources.