Growth of two river crab species of the genus Potamon (Savigny, 1816).

Given that the knowledge of the demography and population regulation is a prerequisite for any action aimed at the sustainable exploitation of endangered species (Kokko and Lindstrom, 1998; Freckleton et al. 2003) and at the biological control of invasive ones (May et al., 1981; Tuyttens et al., 2000; Scalici & Gherardi, 2007), it seems surprising that little is available in the literature about growth (i.e. increase of the length and weigth) and dynamic potentialites (i.e. Von Bertalanffy parameters) of many decapod taxa, particularly river crab species. Growth represents the most useful parameter for providing an estimate of the fitness of a population and of its adaptation to the habitat. In fact, the size of an individual is always correlated to its main biological processes, such as alimentation, predation, and fecundity (i.e. Sparre & Venema, 1996). Understanding crab population structure and dynamics, therefore, holds interest to both managers of freshwater resources and scholars of population dynamics. This study aimed at improving our knowledge about the growth of two river crab species, Potamon fluviatile fluviatile (Herbst, 1785) and P. potamios palestinensis (Bott, 1967), by applying the fish stock assessment principles.