Arthropods (Mar 2023)
Burrow characteristics of the fiddler crab – Austruca sindensis (Alcock, 1900) from mudflats of Gulf of Khambhat, Gujarat, India
Abstract
The present investigation was carried out on the structural characteristics of burrows of the fiddler crab - Austruca sindensis (Alcock, 1900) between March 2021 to January 2022 from the mudflats of Kamboi, Gulf of Khambhat, Gujarat, India. Burrows were selected randomly from upper and middle intertidal zones for burrow casting. The unsaturated resin was poured inside the burrow and allowed to get solidify. The resident crabs were captured for morphological identification and its morphometry (carapace length - CL and carapace width - CW) and sex were recorded. A total of 94 complete burrow cast were used for burrow morphological and morphometric analysis wherein, characteristics including burrow diameter, orientation, length, width, inclination, branching and volume were recorded. A total of 7 different burrow shapes were recorded in which Single tube (27) burrow was prominently observed followed by J-shaped (25), S-shaped (21), Spiral burrows (10), etc. The crab carapace length showed significant positive correlation with carapace width, burrow opening diameter, total burrow length, total burrow depth and burrow volume. Burrow diameters are significantly smaller in the foreshore compared to that of the backshore, suggesting that larger individuals reside along the backshore, where they excavate deeper and large-diameter burrows to minimize chances of desiccation. While, the juveniles were observed utilizing shallow burrows with small opening diameter located near water line. Specific pattern was observed in the burrow temperature in which the burrow temperature dropped significantly at the greatest depth which provides suitable environment to the crab to survive in the harsh environmental conditions.
