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Cobias (Rachycentron canadum) are large fish that live in all the tropical oceans of the world, except for the Eastern Pacific Ocean (EPO). During 2015, a cobia cage culture was initiated in the EPO off Ecuador. Thousands of cobia individuals escaped from the culture, and the location of the escapees is unknown. In this paper, we used a Maximum Entropy (MaxEnt) model to assess the preferential habitat of cobia in a portion of its natural occurrence range and used the model to predict the potential invasion zones of cobia in the EPO. The model performance was satisfactory (75–93% accuracy). Mixed Layer Depth (MLD) was the most important environmental variable. Cobia inhabits waters near the continental shelf, with a shallow MLD. Five important zones of high probability of invasion were detected in the EPO: one in the southern California Current, one in the Central Mexican Pacific, one off Guatemala/El Salvador, one in a latitudinal band that detaches from the coastline of Central America, and one off Northern Chile. There is an important seasonal variation of the zones of high probability of cobia invasion, variation that is apparently related to the seasonal cycle of different large-scale and mesoscale systems. [ABSTRACT FROM AUTHOR]

Studies focusing on the specific identification of the taxonomic cast within the genus Opisthonema are scarce and contradictory, in spite of this species commercial importance and of the potential ecological impact that fisheries may have on the pelagic ecosystem. In this study, the specific composition of thread herrings Opisthonema ( O. bulleri, O. medirastre, and O. libertate) in the southeastern region of the Gulf of California was identified using meristic characters, morphometric data, and mt DNA sequences. In this paper we supported the hypothesis that the commercial catch comprises three evolutionary entities with meristic and morphometric differences. The results were based on the number of ceratobranchial gill rakers, the presence of spicules on the gill rakers, the form of insertion of the gill rakers base onto the ceratobranchial segment, the geometric morphometrics of body shape, and the genetic distances from a fragment of Cytochrome Oxidase Subunit I gene ( COI) of mt DNA. Specimens of Pacific thread herring were obtained from landings of the small pelagic fleet at Mazatlan, Sinaloa during 2011-2012. Taxonomic categories were assigned to 1060 individuals according to the measurement of meristic characters. A total of 228 thread herrings O. bulleri, (n = 76), O. medirastre (n = 76), and O. libertate (n = 76) were used in the morphometric analysis, and 25 specimens ( O. bulleri n = 8, O. medirastre n = 7, and O. libertate n = 10) were used for genetic comparisons. The morphometric results showed differences among the three groups that had been previously identified using meristic characters, giving support to the existence of three discrete morphotypes. The percentage of sequence divergence of the COI gene supports the existence of three clades. Genetic distances were considerably lower within each clade than between clades. The results of this study provide sufficient evidence for the existence of three Pacific thread herring species in the southern Gulf of California. [ABSTRACT FROM AUTHOR]