Morphometric and mitochondrial DNA analyses of the Caribbean red snapper, Lutjanus purpureus (Teleostei, Lutjanidae), in western Atlantic off northern Brazil

Abstract

The present work aims at evaluating the hypothesis that the population of Caribbean red snapper, Lutjanus purpureus Poey, 1867, is segregated into two stock units in northern Brazil, corresponding to eastern and western subareas on either side of the Amazon Environmental Barrier located around 47°W. Evidence has been gathered from space-related modifications in body proportions and genetic variation on sequences of the mitochondrial cytochrome-b gene among individuals. Discriminant analysis showed that 67% of the individuals were identified as belonging to one of the stocks, while 33% may be allocated to either of them. Specimens from the eastern subarea have head, eye diameter and pectoral fin of a larger size than specimens from the western subarea; the reverse being true for body depth, features somehow related to the activities of capture and/or processing of prey. Four different haplotypes were identified: two (A and B) associated to the western subarea and the other two (C and D) to the eastern subarea. It is suggested that fishery management should be conducted considering the existence of two conservation units, within which, data should be collected and analyzed separately to enable administrators to take the appropriate regulatory measures.