Advances in the study of the trophic niche of batoids with distribution in Mexican waters

Published on
21 October 2021

Advances in the study of the trophic niche of batoids with distribution in Mexican waters

Francisco Serrano-Flores, Yassir E. Torres-Rojas, Matthew J. Ajemian, Manuel Mendoza-Carranza, Juan C. Pérez-Jiménez

ABSTRACT:

Batoid (rays and skates) populations are declining worldwide, with unknown ecological consequences due to lacking consolidated data on the trophic ecology of these species. Such trends are particularly disconcerting in Mexican waters, where batoids are heavily exploited by commercial fisheries. To assess the current state of knowledge of batoid diet in this region, we conducted a meta-analysis of 54 published stomach content analysis studies. Trophic niche was assessed from 44 total species, including variations due to sex, ontogeny, season, and region, as well as trophic overlap among species. The species assessed belonged to the taxonomic families Urotrygonidae, Dasyatidae, Potamotrygonidae, Mobulidae, Rhinopteridae, Aetobatidae, Gymnuridae, Rhinobatidae, Rajidae, Arhyncobatidae, and Narcinidae. Most of the diet studies to date were conducted in the Mexican Pacific (n = 24), whereas only three studies have come from the Mexican Atlantic, with 27 additional studies coming from other American countries from the tropical and subtropical region. Crustaceans were reported in more than 50% of the species assessed and were also generally the most important prey item, with either high (76%–100%) and medium-high (51%–75%) importance based on dietary indices from the literature reviewed. While the diet of 40 species (91%) consisted of more than one prey type, feeding strategy analysis (Levin and Shannon–Wiener indices) of 27 species indicated that 25 were specialists and two generalists. Species diets varied with ontogeny (20%), sex (11%), region (11%), and seasonality (9%). According to the reviewed studies, interspecific diet overlap was evident in 36% of species, mainly in the family Urotrygonidae. Batoids were grouped into four trophic guilds: crustacivores (68.1%), annelidivores (primarily polychaetes) (13.6%), molluscivores (11.3%), and piscivores (6.8%), based on the literature reviewed. This study showed that most of the batoids had a specialist crustacean-based diet. Future research should focus on species devoid of dietary data to encapsulate the trophic niche breadth of this group in Mexican waters, particularly from the Mexican Atlantic and surrounding regions.

Marine Ecology, DOI: 10.1111/maec.12687

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