Population Structure and Reproductive Traits of the Porcelain Crab Petrolisthes rufescens (Heller 1861) From Saurashtra Coast, Gujarat State, India

ABSTRACT The current study examines the population structure and reproductive traits of the porcelain crab Petrolisthes rufescens (Heller 1861) among the samples collected from the rocky intertidal region of Shivrajpur village, located on the Saurashtra coast of Gujarat. Understanding the population ecology of this species is crucial for its significant role in ecological processes, such as nutrient cycling, and its potential susceptibility to environmental stressors. Specimens were collected over 12 consecutive months (March 2019–February 2020) from a 500 m 2 area during low tide using the hand‐picking method. A total of 1191 individuals were collected, comprising 552 males, 475 non‐ovigerous females, and 164 ovigerous females. Adult male individuals were significantly larger than adult non‐ovigerous females, with an average carapace length of 9.28 ± 1.32 mm compared to 8.56 ± 1.12 mm in females. The overall and monthly sex ratios were slightly female‐biased (1:1.2). The size‐frequency distribution in both males and females showed an apparent bimodal pattern. Ovigerous females were present year‐round, suggesting that reproduction occurs on a continuous basis. However, a relatively higher proportion of ovigerous females were observed during March–May and August–October at the Shivrajpur coast over the study period. Reproductive biology was assessed by examining egg characteristics, including total number, size, weight, and alongside the carapace length of ovigerous females. A significant positive correlation was found between the size of ovigerous females and their reproductive output, including total egg count (197 ± 87.53), egg mass weight (10.78 ± 8.26 mg), and egg size (0.59 ± 0.09 mm). This study provides baseline data for future research on the species' response to environmental changes and the increasing anthropogenic pressures affecting coastal ecosystems.