Population dynamic of coconut crab (Birgus latro) in Sayafi Island, North Maluku of Indonesia
By: S.E. Widiyanti, Marsoedi, Sukoso, D. Setyohadi
Key Words: Growth, mortality, population dynamic, recruitment, robber crab.
J. Bio. Env. Sci. 8(6), 151-161, June 2016.
Katang kanari or coconut crab (Birgus latro) is economical fish resources in North Maluku, Indonesia. Problems arise when coconut crab was widely captured and caused population declining in number and size. However, information of coconut crab population in North Maluku, including Sayafi Island, has not been recorded properly. The study aims were analyzed and described population dynamics of coconut crab in Sayafi Island for better management. Data collection (total catch, thoracic length, body weight, sex and gonad maturity) was conducted in Sayafi Island from February to September 2013. Analysis of population dynamic of coconut crab included growth, recruitment and mortality parameters. Research result showed that estimation of population size was 43, 434 crabs; density was 26 crabs/ha; W = 0.007 ThL3.052; ThLt = 70 (1 – e -0.09(t+0.048)), and dominated by young cohort. Value of Z = 0.704 year -1, M = 0.388 year-1, and F = 0.320 year -1 indicated that crab mortality due to fishing pressure was higher. The highest number of female crab was non ovigerous female with one recruitment pattern during a year. Value of E0.1 = 0.671; E0.5 = 0.339; Emax = 0.821, and ESayafi = 0.455 indicated that exploitation rate of crab has not been optimal. However there was indication of coconut crab population declining in Sayafi Island.