Lesser Electric Ray, Caribbean Numbfish, Bancroft’s Electric Ray.
A large electric ray with a teardrop-shaped body and a broadly rounded snout. Disc width equal to or slightly wider than long. Anterior disc margins convex. Pectoral fin apices broadly rounded. Eyes large and protruding, larger than spiracles. Spiracles oval-shaped with numerous papillae on posterior margin. Nasal curtain short and wide, posterior margin almost straight.
Pelvic fins broad. Tail broad based, with a pronounced lateral keel. Dorsal fins closely spaced, large, and angled backwards, with broadly rounded apices and convex posterior margins. First dorsal origin over pelvic fin posterior margin. Caudal fin sub-triangular, dorsal and ventral margins straight or mildly convex, posterior margin may be straight, or weakly concave or convex.
Dorsum light brown to greyish brown, often with darker blotches or broken rings. Snout often dark. Lateral keel and posterior margins of fins pale or white. Ventrum white, occasionally with darker blotches.
Maximum length ~65cm. Size at birth ~9cm.
Tropical/subtropical seas. Benthic on soft substrates, sometimes adjacent to reefs, also estuaries and seagrass beds. From shallow inshore water to 35m.
Western Atlantic. From North Carolina, USA to at least the north coast of South America, including the Gulf of Mexico and Caribbean Sea. Records from further south in South America probably refer to the closely related Brazilian electric ray – Narcine brasiliensis.
A reduction in abundance of 98% was previously reported from the northern Gulf of Mexico, which formed the basis of the previous assessment of Critically Endangered published in 2007. However, an updated analysis which examined a number of data sources, including that used in the original assessment, determined that there has been no decrease in the abundance of the Caribbean Numbfish in the northern Gulf of Mexico since 1972 and that the trend in abundance is relatively stable. Levels of bycatch from the United States (U.S.) shrimp trawl fishery are small primarily because the shrimp fishery operates in areas of muddy sediment where Caribbean Numbfish are not found. Based on interactions with commercial fishing gear and the species’ life history (small size and fast growth rate), impacts from bycatch are likely to be low. Species-specific data are lacking from outside of U.S. waters, where the range of the species overlaps with areas of generally unregulated intense inshore fisheries, some of which would be taking this species as bycatch. However, electric rays have limited to no commercial value and are generally discarded. The species was proposed for listing on the U.S. Endangered Species Act and subsequently was determined not to be in danger of extinction globally. Given a lack of evidence of population reduction in U.S. waters where data are available, and which represents a sizable proportion of the range, the species is assessed as Least Concern. However, monitoring is required elsewhere in its range where data are currently not available.
Driggers, III, W.B. & Carlson, J. 2019. Narcine bancroftii. The IUCN Red List of Threatened Species 2019: e.T63142A3121523. https://dx.doi.org/10.2305/IUCN.UK.2019-2.RLTS.T63142A3121523.en. Downloaded on 31 May 2021.
Aplacental viviparous. Litter size 1-15. Annual reproductive cycle.
Feeds mostly on benthic invertebrates.
When pursued, lesser electric rays bolt forward obscured by a cloud of sand and then quickly bury themselves.
In the Leeward Islands, lesser electric rays congregate in shallow bays in January/February.
Reaction to divers
Fairly skittish. Usually moves away before a close approach is possible. May try to deliver a shock and then relocate when threatened.
Seen occasionally on shallow reefs in Florida but generally more abundant further south. In the Leeward Islands, lesser electric rays are quite common in shallow bays and on sandy slopes around reefs.
I have seen aggregations of 30+ animals in 5m depth in sandy bays in Carriacou Island near Grenada. I have also seen numerous animals off deeper sand slopes while diving in Soufriere, Dominica.
Brazilian Electric Ray Difficult to distinguish but pattern sometimes consists of transverse bands, and two very dark blotches on snout. Confined to Brazil and northern Argentina.