Behavioural shift of estuarine mudcrab as biomarker of arsenic exposure in Sundarbans estuary of West Bengal

Abstract

Mudcrab Scylla serrata (Crustacea: Decapoda) in an ecologically and economically important species of Sundarbans Biosphere Reserve was studied for its behaviour under the exposure of toxic arsenic - a common xenobiotic of this area. The behavioural profile of aquatic animals exposed to diverse toxicants are considered as an index to estimate the degree and nature of stress experienced by the animals both in nature and in experimental conditions. Present investigation involved study of selected behavioural shift of S. serrata under the sublethalconcentrations of 1, 2 and 3 ppm of sodium arsenite for 1, 2, 3 and 4 days in controlled laboratory condition. Exposure to arsenic resulted an appearance of selected abnormal behavioural manifestation including tendency of avoidance, hypersecretion of mucoid element and release of excess excretory products. Toxin induced alteration of studied behaviour is indicative to possible shift in the overall physiological functions and biological activities of this important species in its natural habitat. Chronic exposure to 3 ppm of sodium arsenite for 30 days may lead to decline this economically important species in Sundarbans Biosphere Reserve.