Population dynamics of Macrobrachium sintangense and M. lanchesteri in Lake Lido, West Java

Abstract

Macrobrachium is a genus of freshwater prawn widely distributed in tropical and subtropical waters. Its two species found in Lake Lido, i.e Macrobrachium sintangense and M. lanchesteri. Macrobrachium sintangense is an indigenous prawn species from Indonesia while M. lanchesteri is an introduced species. The objective of this study is to identify the growth pattern, mortality rate, and recruitment pattern of both. The study was conducted from July to December 2015. The results show that the growth parameter carapace asymptotic length (CLœ) of M. sintangense and M. lanchesteri were 20.50 mm and 18.50 mm, respectively; and the growth coefficient (K) were 1.02/Year and 1.10/Year, respectively. The exploitation rate of M. sintangense were 0.68 and 0.81 thus both have exceeded the optimum exploitation rate. Therefore, these species can be considered as overexploited. The recruitment of the two species was performed twice per year. During the study, the population of M. sintangense happened to ceased in December 2015. An extra six-month study was conducted to see the recovery of this population, however M. sintangense had been extinct since then. It is suspected that there had been a natural competition between the native M. sintangense and the introduced M. lanchesteri.