IUCN threat status:

Least Concern (LC)

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Urobatis halleri, or Haller's Round Ray, is a species of ray belonging to the family Urotrygonidae, commonly found along the coast of southern California and northern Mexico (Ebert 2006). The ray is named for the son of Major Haller who was stung on the foot in San Diego bay (Babel 1967). He was treated by a Dr. Cooper, who made the first clinical description of Urobatis halleri. This species becomes mature at a wingspan of about 15cm. The ventral surface is white, while the dorsal is grey or brown, getting lighter towards the edges of the discs. The dorsal side also has yellow dots that get smaller and more tightly spaced as they approach the edge of the disc and the disc shape is usually slightly longer than they are wide. About one in 800 rays is born completely black. This species prefers water warmer than 10°C, limiting them to depths of less than about 18m in southern CA. The rays are found in soft bottom habitats, both offshore and in shallow inlets, bays and estuaries which they also use as nurseries. While both ovaries are functional and produce ova, the right ovary is much smaller, and is usually only capable of producing small, nonviable ova. Females may also be capable of storing sperm. These rays swim right along the bottom, then dig in the sand with their discs to find prey, feeding mostly on crustaceans and other benthic (bottom dwelling) organisms. These rays have a spine at the base of the caudal fin (tail) that they use to inject venom as part of their defensive reflex (Babel 1967, Russell 1972). Hundreds of people are stung each year on California beaches. The spines are replaced yearly between August and October, making removal of the spines ineffective for controlling injuries at popular beaches (Lowe 2007).

References:

Babel, J.S. 1967. Reproduction, life history and ecology of the round stingray Urolophus halleri Cooper. Fish. Bull. Calif. Dep. Fish Game 137:104 p.

Ebert, D.A. 2006. Urobatis halleri. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. . Downloaded on 11 October 2012.

Lowe, C.G., G.J. Moss, G. Hoisington, J. J. Vaudo, D.P. Cartamil, M.M. Marcotte, Y.P. Papastamatiou. 2007. Caudal Spine Shedding Periodicity and Site Fidelity of Round Stingrays, Urobatis halleri (Cooper), at Seal Beach, California: Implications for Stingray-related Injury Management. Bulletin of the Southern California Academy of Sciences 106 (1): 16–26.

Russell, F. E. 1972. Some Chemical and Zootoxicological Properties of Stingray Venom. Professional Staff Association of Lac/Usc Medical Center Los Angeles Calif – Rept. no. 19, 1 Oct-31 Dec 71.

Unreviewed

Creative Commons Attribution 3.0 (CC BY 3.0)

© Zoe Adams, Cooper Thomas

Source: Biology 260 Occidental College

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