Food and Feeding Habits of Wedge Clam (Donax cuneatus) Off Thoothukudi, Gulf of Mannar, India

Background: Bivalves are benthic animals existing in coastal habitats, particularly mudflats and tidal. Because of their availability, rich protein content and cheaper cost, they contribute a major portion of the small-scale fishery resource worldwide. Limited information has been available on the food-feeding and habitat structures of bivalves along Indian waters. Therefore, the present investigation was carried out to know the food-feeding and habitat preferred by wedge clam, Donax cuneatus off Thoothukudi, Gulf of Mannar, India. Methods: Soil, water and wedge clam samples were collected from the selected site from September 2019 to March 2021 and soil texture, water quality parameters and gut contents were analyzed at the laboratory. Result: During the study period, salinity, water temperature, pH and dissolved oxygen (DO) were in the range from 31-37°C, 24-28°C, 7.7-8.7 and 4.1-5.8 mg/l, respectively. Wedge clams were mainly observed at sandy beaches up to 10 cm in depth. Donax cuneatus mainly feeds on detritus (65%), followed by phytoplankton (31%) and zooplankton (4%). Hence, the diverse fluctuation of food particles, season-specific food and feeding biology and local environmental conditions at the studied region might be the responsible features for the availability of Donax cuneatus.