Population structure and reproductive biology of Clibanarius rhabdodactylus Forest, 1953 (Crustacea: Anomura: Diogenidae) in Gujarat state, India

The population structure of a hermit crab, Clibanarius rhabdodactylus Forest, 1953 (Diogenidae), was studied in the rocky intertidal region of Veraval, located on the Saurashtra coast, Gujarat state, India. Monthly sampling was carried out from March 2021 to February 2022 during low tide time using the handpicking technique, while the catch per unit effort method was employed by one person during the period of 4 h in an area of 500 m2. The collected individuals were classified as male, non-ovigerous female, and ovigerous female. Size (mm) and weight (g), egg size, number, and egg mass weight were recorded and fecundity was calculated. A clear sexual dimorphism was observed, with males being significantly larger than females. The overall sex ratio was female biased. The overall size frequency distribution showed bimodal distribution in male while unimodal in females. Ovigerous females occurred throughout the year with peaks in January to June and September to October, showing a continuous reproductive pattern of the species. The total number of eggs, size of eggs, and total weight of egg mass showed a positive correlation with the shield length and body weight of the ovigerous females.