Population dynamics of mantis shrimp, Harpiosquilla harpax in the coastal waters of Pantai Remis, Perak, Peninsular Malaysia

This study estimated the length-weight relationship, sex ratio and population parameters of mantis shrimp, Harpiosquilla harpax from the coastal waters of Pantai Remis, Perak, Malaysia between February ۲۰۱۲ and October ۲۰۱۲. Total length and weight of ۸۰۴ specimens of H. harpax were measured and the sex ratio was ۱: ۰.۸۳ (M: F). Males of H. harpax were dominant over the females throughout the study period. The value of relative growth coefficient (b) for H. harpax was ۲.۶۹۸ for males and ۲.۸۸۴ for females. For the length-weight relationship, the species exhibited negative allometric growth for males, females and combined sexes. The L∞ and K of H. harpax was ۱۸.۳۸ cm and ۱.۱۰ yr-۱ for males and ۲۱.۵۳ cm and ۰.۷۵ yr-۱ for females. The growth performance index (φ') was calculated as ۲.۵۷ for males and ۲.۵۴ for females. Total mortality (Z), natural mortality and fishing mortality was found to be ۴.۰۸۴ yr-۱, ۲.۲۴۷ yr-۱ and ۱.۸۳۷ yr-۱ for males whereas ۳.۲۵۹ yr-۱, ۱.۶۷۴ yr-۱, ۱.۵۸۵ yr-۱ for females, respectively. The recruitment pattern of the species was continuous throughout the year for males and females. The exploitation level (E) of H. harpax was estimated at ۰.۴۴۹ for males and ۰.۴۸۶ for females. It is revealed that the stock of H. harpax was very close to optimum level of exploitation (E = ۰.۵۰) in the coastal waters of Pantai Remis, Perak, Malaysia.