ESR prepress abstract  -  doi: 10.3354/esr00799

Is the lesser electric ray Narcine bancroftii a species on the brink of extinction?

John K. Carlson*, Adam G. Pollack, William B. Driggers III, José I. Castro, Adam B. Brame, Jennifer L. Lee


ABSTRACT: Among rays inhabiting coastal waters of the United States in the western North Atlantic Ocean, a species of potential concern is the lesser electric ray Narcine bancroftii. The most recent International Union for the Conservation of Nature (IUCN) Red List Assessment indicates the species is Critically Endangered, which represents the highest risk of extinction based on IUCN criteria. The basis of this alarming designation was a reported 98% decline in abundance based on analyses of a long term, fisheries-independent trawl survey conducted in the northern Gulf of Mexico since 1972. The status of this species generated considerable concern within the conservation community, prompting a petition for its inclusion on the US Endangered Species Act. We critically examined all available sources of data relative to the abundance of lesser electric ray, including those utilized in the original analysis, and found lesser electric rays do not appear to be at risk of extinction. Contrary to the earlier analysis, we found no evidence of decline in the relative abundance of lesser electric rays, with trends in abundance being relatively flat with high variability. Our analyses determined the previously reported study did not address major changes over time in survey design and disregarded the strong habitat preference of lesser electric rays. It is critical that the best possible information be used when considering the conservation status of a given species to minimize undue burdens and insure that increasingly limited resources are applied to the recovery of those species truly in peril.