Abstract
Sharks, skates, and rays (elasmobranchs) are experiencing global population declines, leading to heightened concern regarding the impacts of target and bycatch fishing on their populations. Globally, market mislabeling of unsustainably harvested fish can lead to confusion about species identity and origin, mask unsustainable fishing practices, and inhibit recovery of depleted populations. Therefore, it is important to increase transparency about the identity of species sold to address the potential impact of mislabeled or illegally harvested threatened elasmobranchs. We used DNA barcode sequencing to identify the species composition of rays sold in fish markets and supermarkets in La Paz, Baja California Sur, Mexico, an important market for small-scale fisheries in Northwestern Mexico. We identified 131 samples from 36 market locations collected between 2020 and 2022 representing 14 species belonging to eight families. None of the samples were labeled using local names for individual species by the seller; instead, they were sold under four categories: mantarraya, pescado seco, machaca, and cubana seca. The most common species identified by genetic analyses were diamond stingray (Hypanus dipterurus) (n = 47), longtail stingray (H. longus) (n = 37), and California butterfly ray (Gymnura marmorata) (n = 11). Greater than 78% of the samples identified are considered threatened by the IUCN Red List. This included two species of devil ray (Mobula munkiana and Mobula thurstoni), both of which are federally protected in Mexico. The use of overly broad seafood commercial names for threatened ray species is concerning, given that most species exhibit vulnerable life history characteristics and have documented population declines. We recommend expanding point of purchase identification for fresh products weighed and packaged in markets with Mexican authorities to better understand the extent of elasmobranch fishing and to identify which fisheries and species require increased action for their conservation in the Mexican Pacific.