Population characteristics of the mole crab, Hippa adactyla Fabricius, in the intertidal sediment at Kavaratti atoll, Lakshadweep islands

Some population characteristics of a little known mole crab Hippa adactyla Fabricius from the sandy intertidal habitat of Kavaratti atoll, Lakshadweep islands, were studied for understanding the resource potentials besides some features of breeding behavior. The study is based on the detailed examination of 1140 specimens collected from the intertidal beach during November 1993. The specimens were in the size range of 8.84-22.56 mm carapace length (CL). The population of mole crab consisted of three modal size classes, dominated by the newly recruited or the '0' year individuals. The size at maturity of female crabs (estimated from the smallest egg bearing females) was 10.14 mm CL. The egg bearing population constituted more than 60% of the total observed specimens of mole crab, and over 80% of the 'I' and 'II' year population carried eggs. Mean fecundity was estimated to be 1628.61 ± 853.13 eggs/female/clutch, with a large variation in the total number of eggs per female. Regression analysis of fecundity with length and weight (wet weight) revealed that fecundity correlated better with length (r = 0.86) than weight (r = 0.82). However, the differences between regression values were insignificant. This mole crab species possess great potential for commercial exploitation especially in oceanic environment, like Lakshadweep islands, where food resources are limited. The information on the population parameters provided here therefore would be useful for sustainable exploitation.