Directed artisanal fisheries and incidental catch among trawl fisheries and other artisanal fisheries using gillnets, longlines, or traps.

Dasyatis dipterura represents a primary component of artisanal elasmobranch fishery catches of the Pacific coast of México and the Gulf of California (Bizzarro et al. 2000, R. Hueter et al. unpublished data, Smith 2004, Bizzarro 2005). Its contribution to the fishery is likely underestimated due to the lack of species-specific landing information and potential misidentification. Although present in artisanal landings throughout the year, catches of this stingray are highest during the summer and fall (Notarbartolo di Sciara 1987; Bizzarro et al. 2000). Dasyatis dipterura is the second most abundant batoid landed in coastal waters of Sonora, México, comprising ~19% of all batoid landings in seasonal surveys conducted in 1998 and 1999 (R. Hueter et al., unpublished data, Márquez-Farías 2002). This species is targeted during primarily summer months in Bahía Almejas, located in the southern portion of the Bahía Magdalena lagoon complex, Baja California Sur, México. In this embayment, it is most abundant batoid species landed in August (~43%) and the fourth most abundant batoid in June landings (~8%) (Bizzarro 2005). Individuals are primarily captured in demersal gillnets in which their tail spines are entangled. This method of entanglement allows a wide range of mesh sizes to be effective for capturing juveniles as well as adults. Juveniles comprised the majority of individuals landed in the Bahía Magdalena lagoon complex artisanal elasmobranch fishery during 1998?2000 (Smith 2004, Bizzarro 2005, Bizzarro and Smith in preparation).

Based on records from exploratory fishing surveys, it is likely that this species represents a significant component of trawl bycatch fisheries (especially shrimp trawl bycatch) in the Mexican Pacific (Mathews and Druck-Gonzalez 1975, Flores et al. 1995). No information is available on the species? actual contribution to bycatch in other artisanal or trawl fisheries in México, or through its Central and South American range.

Many coastal embayments and mangrove lagoons in north Pacific México, which serve as habitat for D. dipterura, are being altered for the purpose of shrimp farming. Although these activities are presently limited, their expected increase could detrimentally alter suitable habitat for this species (Bizzarro pers. obs.).