Population dynamics of mantis shrimp (Gonodactylus chiragra Fabricius, 1781) in Batukalasi waters, South Sulawesi, Indonesia

Abstract

The purpose of this research was to determine several population dynamics parameters of a mantis shrimp (Gonodactylus chiragra) population including growth, mortality, exploitation rate, and relative yield per recruit. Mantis shrimp were sampled from the waters around Batukalasi, South Sulawesi Indonesia from 16th June to 21st July 2019. Each specimen was measured, weighed and the sex determined. Growth parameters were estimated using the Von Bertalanffy equation. Natural mortality (M) was estimated using Pauly’s empirical equation. Total mortality (Z) was estimated using the Beverton and Holt equations. Fishing mortality was calculated from the equation Z = F + M. The exploitation level and relative yield per recruit were estimated using the Beverton and Holt equations. These analyses were conducted in the FAO-ICLARM Fish Stock Assessment Tools II (FISAT II) program. The 707 mantis shrimp samples were collected comprised of 245 females and 462 males. The growth rate coefficient was higher in male than female mantis shrimps, while male mantis shrimps reached their asymptotic length faster than females. For both male and female mantis shrimps, the estimated natural mortality was higher than fishing mortality, indicating the stock is not over-exploited. The relative yield per recruit was below the optimum value for both female and male mantis shrimp (0.035 and 0.046, respectively).