Shell utilization pattern of the Hermit crab Clibanarius rhabdodactylus Forest, 1953 on rocky shores of the Saurashtra coast, Gujarat State, India

The present study deals with gastropod shell utilization of the hermit crab, Clibanarius rhabdodactylus Forest on the rocky intertidal zone of the Saurashtra coast, Gujarat State, India. Collection of the specimens was carried out using a handpicking method in June and December 2018 during low tide. The hermit crab weight (HW) and shield length (SL) were measured and sorted in different class intervals of 1 mm each. Gastropod shells were identified and morphological variables such as shell dry weight (DW), shell length (SHL), shell volume (SHV), shell aperture length (SAL), and shell aperture width (SAW) were recorded. A total of 2000 individuals of C. rhabdodactylus were collected, occupying 29 different species of gastropod shells. Males and nonovigerous females occupied a greater number of gastropod shell species (25 and 27 respectively) as compared to ovigerous females (23 species). Males and ovigerous females preferred larger shells as compared to nonovigerous females. Cerithium caeruleum (Sowerby II) (67.1%) was the highest occupied gastropod shell species followed by Lunella coronata (Gmelin), Tenguella granulata (Duclos) and Turbo bruneus (Roding). Regression analysis showed a moderate relationship between the different morphological variables of hermit crabs and gastropod shells; the highest values of coefficient of determination were obtained between hermit wet weight and gastropod shell dry weight. The values of relationship between different morphological variables of hermit crabs and gastropod shells suggest that shell architecture has a significant impact on shell utilization patterns of C. rhabdodactylus.