Acute toxicity of three pesticides and their effect on the behaviour of the edible crab Scylla serrata (Forskal)

Abstract

Technical grade heptachlor, phosalone and carbaryl were tested for acute toxicity to the edible crab Scylla serrata. The 96 h LC 50 values of the three pesticides were 322, 406 and 566mug/l respectively. Heptachlor produced instant hyperactivity, hyperexcitability and finally death due to exhaustion. However, phosalone and carbaryl induced similar effects resulting in gradual death. Profuse defaecation was observed in crabs exposed to phosalone and carbaryl