Ontogenetic variation of food habitats of Trichopsetta ventralis (Pleuronectiformes: Bothidae) in the southern Gulf of Mexico

Abstract

Background. This study of feeding provides biological information on the species and its ecosystem function. Species of the family Bothidae are characterized by their demersal habits and are part of the accompanying fauna of shrimp. Goals. This study quantified and described the diet and trophic ontogenetic variation of Trichopsetta ventralis (Pleuronectiformes: Bothidae) collected at 20 locations with a shrimp trawl in the southern portion of the Gulf of Mexico at depths between 41 and 355 m. Methods. Prey were analyzed using area (volumetric), gravimetric (weight), occurrence frequency, and Relative Importance Index (RII) methods. The number of size intervals required to evaluate ontogenic trophic variation was obtained by considering the maximum size minus the minimum, number of intervals, and total samples. Results. Trophic analysis was realized in 167 specimens between 5.5 to 14.8 cm standard lengths. We identified 46 food items, grouped in six trophic categories. Within these categories, fish were the principal trophic component (RII: 76.4%), a preference that remained constant through the ontogeny, but in different proportions among the size classes recorded. The standardized Levin index showed that T. ventralis has a tendency toward specialization (0.07). Conclusions. The results obtained provide information about the function of this sole in the food web of the southern Gulf of Mexico and contribute to the knowledge of the trophic dynamics of this species.