Intraspecific diversification of the red snapper <em>Lutjanus purpureus</em> Poey in North and Northeast of Brazil

Abstract

The red snapper, Lutjanus purpureus Poey (Perciformes, Lutjanidae), is captured along the North and Northeast coast of Brazil. It consists of one of the main fishing resources of these areas, being considered economically important as source of exchange value. This work has verified the occurrence of intro-specific diversification of the red snapper in the North and Northeast of Brazil. A total of 556 individuals were investigated among Amapá (319), Pará (176) and Maranhão (61). Sex ratio has shown that 43.71% were male and 56.29% female. The higher proportion of females is statistically significant according to χ² test. The results of ANOVA showed significant differences of morphometrical variables in all areas studied. In order to show which averages presented significant difference, the Tukey’s test was used, and revealed that from the 48 comparative analyses, 100% were shown significant. Each area (AP, PA and MA) presented significant difference for each one of the morphometrical variables. To calculate the overlap degree, the method was used by comparison of averages for morphometrical characters. Out of 112 analyses, 46.43% presented diversification process at the intro-specific level, possibly suggesting the existence of natural barriers and/or geographical isolation. This information may be considered very important for the correct formulation of environmental policies.