Biometric relationships of the Argentinean prawn Artemesia longinaris Decapoda Penaeidae in the south-western Atlantic

Biometric relationships of size and weight were estimated for the Argentinean prawn (Artemesia longinaris), a new commercial penaeid prawn exploited in the south-western Atlantic. Morphometric and meristic traits were used to elucidate population structure of this species along its distribution area. The morphological relationships were stimated by a simple linear regression, considering total length (TL) as the dependent variable. The males collected in southern Brazil, an area under influence of the Subtropical Convergence, presented a slightly lower TL increment than females. A marked reduction in slopes of males between populations from southern Brazil was observed in autumn and winter. Additionally, relative growth in length of males from Argentina is similar to that observed during autumn and winter in southern Brazil. The other morphometric and meristic variables used also indicated higher similarities between southern Brazil and Argentina, which may be explained by relative growth associated to water temperatures or migration during winter, taking advantage of the oceanographic systems connecting both sites. Moreover, the population from Rio de Janeiro seems morphologically apart from the others, forming a separate unit stock