Molecular and morphological identification of larvae of Carangidae (Teleostei, Carangiformes) species from southern Gulf of California

The description of diagnostic morphological characters and DNA barcoding of fish larvae from nine species of the carangid family are provided from specimens collected during a weekly zooplankton time-series (2016–2017) at Cabo Pulmo National Park, Gulf of California, Mexico. Five nominal species (Caranx sexfasciatus, C. caballus, Naucrates ductor, Selar crumenophthalmus, and Selene peruviana) and three morphotypes of Decapterus spp. and one of Caranx spp. were identified and separated based on morphological, meristic, and pigmentary diagnostic characters. All larvae were genetically sequenced for a fragment of the cytochrome c oxidase subunit I mitochondrial gene. Sequences of larval Caranx and Decapterus showed high genetic similarity (> 99%), low intraspecific divergence (< 1%), and an interspecific divergence between 6% and 11%, allowing the discrimination of diagnostic pigmentation patterns of fish larvae among three sibling species from each genus: Caranx (C. caballus, C. caninus, and C. sexfasciatus) and Decapterus (D. macarellus, D. macrosoma, and D. muroadsi). DNA barcoding supported the presence of Caranx caballus, C. caninus, C. sexfasciatus, Decapterus macarellus, D. muroadsi, Selar crumenophthalmus, and Selene peruviana, and for the first time Naucrates ductor and D. macrosoma at the CPNP. Abundance of these nine species (confirmed molecularly) was estimated throughout the 2016–2017 weekly time series. Decapterus macarellus and Caranx caninus were the most abundant species. The morphological and molecular taxonomic methods allowed us to infer the species number and abundance of these commercial species at the CPNP to improve conservation in protected areas and fishery management.