Morphometrics of red swamp crayfish from a temporary Marsh (Donana National Park, Sw. Spain) and a temporary stream (Pardiela Stream, S. Portugal)

Two populations of Procambarus clarkii from a temporary stream and from a temporary freshwater marsh, were studied. Morphometric relations (total length-wet weight; carapace length- wet weight; wet weight-dry weight, ash content, organic matter and water content) and sex ratio were considered. The length-wet weight relationships showed non-isometric growth for both populations (males and females in both reproductive Forms). Main difference for growing specimens in the two populations is related to the larger increase in weight in the Portuguese river population. No differences were found between sexes for organic matter and water content of tissues in Form I or [I. Phenotypic differences are probably due to sex, while variations on organic and mineral contents seem to be related to reproductive Forms. Habitat differences between the two ecosystems are probably the major factor responsible for the variations observed.