ESR 32:177-186 (2017)  -  DOI: https://doi.org/10.3354/esr00799

Revised analyses suggest that the lesser electric ray Narcine bancroftii is not at risk of extinction

John K. Carlson1,*, Adam G. Pollack2, William B. Driggers III3, José I. Castro4, Adam B. Brame5, Jennifer L. Lee5

1National Marine Fisheries Service, Southeast Fisheries Science Center—Panama City Laboratory, 3500 Delwood Beach Road, Panama City, Florida 32408, USA
2Riverside Technology, Inc., National Marine Fisheries Service, Southeast Fisheries Science Center—Mississippi Laboratory, PO Drawer 1207, Pascagoula, Mississippi 39567, USA
3National Marine Fisheries Service, Southeast Fisheries Science Center—Mississippi Laboratory, PO Drawer 1207, Pascagoula, Mississippi 39567, USA
4National Marine Fisheries Service, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, Florida 33149, USA
5National Marine Fisheries Service, Southeast Regional Office, 263 13th Ave S, St. Petersburg, Florida 33701, USA
*Corresponding author:

ABSTRACT: Among rays inhabiting US coastal waters 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 under 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 investigation determined that analyses of previous trawl surveys 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 ensure that increasingly limited resources are applied to the recovery of those species that are truly in peril.


KEY WORDS: Generalized linear model · Trawl · IUCN Red List · Endangered Species Act


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Cite this article as: Carlson JK, Pollack AG, Driggers WB III, Castro JI, Brame AB, Lee JL (2017) Revised analyses suggest that the lesser electric ray Narcine bancroftii is not at risk of extinction. Endang Species Res 32:177-186. https://doi.org/10.3354/esr00799

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