Introduction

Reared in fresh water (freshwater prawn 410 000 tonnes in tropical environments, Crayfish 105 000 t in temperate environments) and in seawater (Chinese crab 440 00 t, tropical shrimp 2 650 000 t). While the freshwater shrimp and Chinese crab represent protein sources for local populations, shrimp farming is aquaculture for export. This explains why the low tonnage (6.2 % of world aquacultural production) accounts for 20.5 % of the value of aquatic products. This “pink gold” represents a highly important part of national revenue in some tropical countries and is a relatively new form of aquaculture (1980).