Morphological differentiation of southern pink shrimp
Farfantepenaeus notialis (Crustacea, Decapoda) constitutes about 70% of the total shrimp catch in the Colombian Caribbean. In this study, we examined morphological characteristics of F. notialis to investigate stock differentiation, provided biological data such as size at 50% sexual maturity and discussed the importance of this information to fisheries management. The study was conducted in the Colombian Caribbean Sea from June to December of 2004 in four locations: Uraba gulf, Morrosquillo gulf, Amansaguapos, and La Vela cape. Individual shrimp were measured according to ten body segments and sex determined. We used discriminant function analysis (DFA) of size-adjusted data to generate two-dimensional plots of the morphometric indices to test for geographic variation in morphometry by mean of canonical dimensions. The length-frequency distributions showed statistically significant differences between the measurements of both sexes, males were smaller than female in all measures. In females, size range was 16 to 46 mm cephalothorax length (CL) and size at sexual maturity (CL50%) was 30.6 mm. Size range was 19 to 32 mm (CL) for males. The DFA of morphological differences between individuals (female/male) showed strong overlapping and no clear separation between regions. We did not find morphometric variability between regions, which indicates a single population of F. notialis from the morphometric point of view.
Auteurs du document :
Jorge Paramo, Ulrich Saint-Paul
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Mots clés :
Morphometrics, Sexual dimorphism, Stock identification, Shrimp, Penaeidae, Colombia