Horizontal and vertical distribution of Abralia spp. paralarvae in the Caribbean Sea with morphological and molecular notes

the Caribbean Sea and adjacent areas, squids of the genus Abralia are a key component in the cephalopod community. However, the distribution and abundance of their paralarvae in this region are unknown, as well as their morphology in early development, making their identification difficult. In the present study, paralarvae of Abralia spp. from surface neuston, subsurface neuston, and multiple opening and closing nets and environmental sensor system (MOCNESS; 0-58 m) tows carried out in the Caribbean Sea were identified, describing the horizontal and vertical distribution of their abundance and their morphology and molecular identity. The greatest abundance of Abralia spp. was recorded in subsurface tows, distributed mainly off Chinchorro Bank, Cozumel, and Honduras, and in a stratum of 38-48 m depth in MOCNESS tows. Paralarvae showed evidence of ontogenetic migration with larger sizes distributed at greater depths. Sixty-eight percent of Abralia spp. had sizes of 1.1-2.0 mm mantle length (ML), indicating that the Mesoamerican Barrier Reef System is an important area in the spawning and development of the genus. Twelve paralarvae were sequenced using the Cytochrome Oxidase I gene (COI) resulting in the presence of two species: Abralia redfieldi and Abralia veranyi (99.01%-100% similarity), which could not be individually identified using the morphological analysis. However, we confirmed their geographical overlap along the Caribbean Sea and described the general morphology of the paralarvae between 1.1-6.0 mm ML.

Automated summary

In this study, the horizontal and vertical distribution, abundance, morphology, and molecular identification of Abralia spp. paralarvae in the Caribbean Sea were described. The greatest abundance of Abralia spp. was found in subsurface tows, mainly distributed off Chinchorro Bank, Cozumel, and Honduras, and in a depth stratum of 38-48 m in MOCNESS tows. Evidence of ontogenetic migration was observed with larger paralarvae distributed at greater depths. Two species, Abralia redfieldi and Abralia veranyi, were identified using genetic analysis but could not be distinguished based on morphology. The study confirmed their geographic overlap in the Caribbean Sea and described the general morphology of the paralarvae between 1.1-6.0 mm mantle length.