Differences in enzymatic activity in wild long-arm river prawns, macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae), from different habitats

Studies on the nutrition of wild populations of freshwater prawns, valuable in the determination of feeding habits and requirements, are scarce or inadequate. We analyzed the digestive tract of individuals of Macrobrachium tenellum (Smith, 1871) (Palaemonidae) sampled from three different coastal habitats (an estuary, a lagoon, and a river) in the southeastern Mexico Pacific coast to determine if individuals show any variations in their enzymatic activities. Prawns of different size (adult or juvenile) showed the most significant differences among them in the kind and amount of enzyme activity, whereas location and sex differences resulted in less significant differences. Results suggest that feeding habits and not habitat, are the main cause of differences between age classes.