Carapace width-weight relationship and condition factor of Austruca annulipes in mangroves of Penang Island

Abstract

Carapace width-weight relationship and relative condition factor (Kn) of Austruca annulipes were estimated from 2086 individuals comprising 1503 males and 583 females. Crabs were sampled from mangroves of Teluk Tempoyak and Pulau Betong during the study period of March 2017 to February 2018. Monthly sampling of crabs was conducted using hand catch method (catch per unit effort (CPUE)) with captured crabs counted as number of crabs/15 min/4 m². Data recorded was analysed in four categories; sex, dry and wet months, five size classes and sampling site. The carapace width-weight relationship of male and female crabs was significantly positive for the four categories with overall samples indicating positive allometric growth, except for males in the size class of 1.70 – 1.99 cm, and females in the size class of 0.80 – 1.09 cm that were characterized by negative allometric growth. The values of mean relative condition factor (Kn) of A. annulipes was higher than 1 indicating that mangrove in Penang Island provide favourable habitat condition for the growth of A. annulipes.