Recognizing Species from Commercial Catches: Molecular and Morphometric Analyses of Scomberomorus spp. off the Mexican Pacific Coast

This study addresses variations of mtDNA and otolith morphometrics in Scomberomorus concolor and Scomberomorus sierra collected along the Mexican Pacific Coast and Gulf of California (GC) in 2002, 2007 and 2008. The catches of GC are reported without distinguishing species, serious problem account that S. concolor is included in the red list by the IUCN. For molecular identification a 592 bp fragment of the 16SrRNA gene was used, and a 410 bp fragment from the mtDNA control region was analysed. The 16SrRNA analysis gene generated two clades, corresponding to each species, which could only be distinguished from two nucleotide sites. The mtDNA sequences maintained the detected lineages, even when both species presented elevated polymorphism in relation to their levels of divergence. For morphometric analysis, a first analysis included samples of fish obtained in 2007 that were genetically identified. A second analysis included fish captured in the central GC that were identified using meristic criteria. Both shape analysis, generated statistically significant classification, the allocation per species was 100%, whereas the allocation of the fish identified using meristic characters was 95%. The deformation grids identified the dorsal zone of the otolith as the origin of the discrimination between species and the criterion for separation.