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Email the author (Login required) First record and biological data of juvenile Dosidicus gigas in the Gulf of Tehuantepec, eastern Central Pacific Ocean
Submited: 2025-08-14 14:33:50 | Published: 2026-10-25 11:44:00
DOI: https://doi.org/10.3856/vol54-issue5-fulltext-3515
Abstract
The Humboldt squid, Dosidicus gigas D'Orbigny, 1835, is endemic to the eastern Pacific. Knowledge of its biology is largely limited to commercial-sized adults, leaving juveniles scarcely documented. This study provides the first reference on the distribution, sex ratio, and feeding of juvenile D. gigas in the Gulf of Tehuantepec (GT). The study was based on 403 juveniles collected in April 2022 aboard the RV Dr. Jorge Carranza Fraser (IMIPAS). The field sampling consisted of 50 fishing hauls, 12 of which were positive for juveniles of D. gigas. We identified three size classes: I (11.0-29.9 mm mantle length, ML, undifferentiated); II (30-59.9 mm); and III (60-99.9 mm). Females >60 mm showed positive allometric growth. Individuals of both sexes and across size classes II and III consumed all four prey groups, with planktonic crustaceans dominating their diet. Fish consumption increased in size-class III. Significant differences in prey frequency of occurrence among the three size classes indicate an ontogenetic dietary shift, with prey selection changing significantly as size increases. Our results also indicate that juvenile D. gigas are widely distributed in the oceanic zone west of the GT, where they feed mainly on euphausiids, mesopelagic fishes, and small squid. Therefore, productivity pulses associated with the Tehuano winds (mainly from November to April) and the formation of mesoscale eddies in the GT may provide favorable environmental conditions for juvenile D. gigas. The occurrence reported here may be related to this upwelling. Despite limitations due to the lack of year-round data, this study provides new insights into the biology of juvenile D. gigas in the GT.
