Ecology, Environment and Conservation Paper

POPULATION DYNAMICS OF CARCHARHINUS MELANOPTERUS CAUGHT FROM SOUTHERN MAKASSAR STRAIT, INDONESIA

Faisal Amir, Achmar Mallawa and Joeharnani Tresnati

Abstract

Blacktip reef shark Carcharhinus melanopterus is the species dominant catch of the traditional fisheries using bottom gill nets and bottom longline in South Sulawesi Province, Indonesia. This study aims to determine several C. melanopterus population dynamics parameters include growth rate, fishing mortality, exploitation rate, and relative yield per recruitment. Data collection of fish length was carried out from July to September 2020. Data were collected from all captured sharks landed at fish landing sites Paotere and Beba twice a week. Population growth is analyzed using the von Bertalanffy equation exponential growth, the value of L, K, by ELEFAN method and t0 by Pauly method. The total mortality (Z) was estimated from the catch curve, and the natural mortality (M) was obtained from Pauly’s empirical relationship based on L, K, and the mean temperature of the environment. FISAT-II software’s help estimated the size of length at first capture (Lc). Finally, estimating the optimum level of exploitation rate (E) was carried out using the relative yield-per-recruit model (Y’/R) of Beverton and Holt. The results showed that the population of C. melanopterus in the Makassar Strait’s southern waters had a low population growth rate with an infinity length (L) of 161.5 cm and a growth rate coefficient (K) of 0.25 yr-1, during the t0 value of -0.4247 yr. The total mortality (Z) of 1.05 yr-1, the natural mortality (M) of 0.45 yr-1, fishing mortality (F) 0.6 yr-1, and the size of length at first capture (Lc) of 99.64 cm. The estimated rate of exploitation (E) was below the optimum rate of exploitation. It seems that the population of C. melanopterus in this area is under-exploited.