Inhibition and recovery of selected target enzyme activities in tissues of penaeid prawn, Metapenaeus monoceros (Fabricius), exposed to different insecticides.

The target enzymes, acetylcholinesterase (for phosphamidon and carbaryl) and Mg2+ ATPase (for DDT and fenvalerate) have been assayed during exposure and reclamation of these insecticides in M. monoceros. Toxicity of these insecticides are in the order: fenvalerate greater than DDT greater than carbaryl greater than phosphamidon. Reclamation studies show that fenvalerate is rapidly degradable while DDT is slowly degradable. It is suggested that pyrethroid, organophosphate and carbamate insecticides may be preferred over organochlorine compounds in farm operations.