The thesis deals with the results of the study of the population characteristics of the marine penaeid prawn, Penaeus monodon from South India. The present findings on the morphometric and biochemical genetic structure support the hypothesis that the populations of P.monodon of South India have homogeneous stock structure. To the contrary, the significantly different random amplified polymorphic DNA (RAPD) profiles in samples of Kochi and Chennai support the hypothesis that east and west cost populations of P.monodon are separate stocks.