Urobatis halleri 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Urotrygonidae

Scientific Name: Urobatis halleri
Species Authority: (Cooper, 1863)
Common Name(s):
English Round Stingray
Urolophus halleri Cooper, 1863
Taxonomic Source(s): Eschmeyer, W.N. and Fricke, R. (eds). 2015. Catalog of Fishes: genera, species, references. Updated 1 October 2015. Available at: (Accessed: 1 October 2015).
Taxonomic Notes: The species was originally placed in the genus Urolophus, but was later moved by Garman (1913) into his newly erected genus Urobatis, which included all eastern Pacific and western North Atlantic round stingrays. The genus Urolophus is restricted to the stingarees found in the Indo-West Pacific. Both genera are frequently seen in the literature for eastern Pacific forms, but current research suggests that Urobatis is the correct genus (Ebert 2003). Urobatis is sometimes placed in the family Urolophidae, however this placement is incorrect and the family Urotrygonidae is valid (McEachran et al. 1996).

The relationship between U. halleri and the sympatric U. maculates and U. concentricus is currently under investigation (J. McEachran pers. comm.). These species may be valid separate species or may be synonymized in the future.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2015
Date Assessed: 2014-11-25
Assessor(s): Lyons, K., Ebert, D.A. & Lowe, C.G
Reviewer(s): Farrugia, T.J. & Lawson, J.
Facilitator/Compiler(s): Walls, R.H.L. & Dulvy, N.K.
The Round Stingray (Urobatis halleri) is a small, common inshore stingray found along the coastal waters of the eastern Pacific. It is distributed from northern California to Panama. This species has a generation length of 8.9 years and an annual reproductive cycle, making it a relatively productive batoid. This stingray is not targeted but is taken incidentally by commercial, recreational and artisanal fisheries. It is generally discarded, as its small size and large tail spine make it an undesirable target species, however the tail is usually cleaved off before it is returned to the sea, which increases discard mortality. In southern California, the population abundance of this stingray fluctuates seasonally but seems overall to be stable or increasing. In the Gulf of California (Mexico) this species was rarely encountered in artisanal gillnet and trawl fisheries along the coast of Baja California Sur, but was a dominant bycatch species in commercial shrimp trawl fisheries. Exploitation rates in these Mexican commercial shrimp trawl fisheries exceeded biological reference points, suggesting that this species may be overexploited, however, no time series data are available. Nothing is known of the state of exploitation or population status for this species in Central America. No species-specific conservation measures are in place, however, marine protected area implementation (leading to a redistribution of fishing effort) in California may have positive effect on this species. As the species appears to be generally abundant where it occurs, is relatively productive, and appears to be stable or increasing in the northern part of its range, this species is assessed as Least Concern. However, this stingray may be overexploited as a bycatch species in commercial shrimp trawl fisheries operating in the Gulf of California. More data are needed in order to determine how this high exploitation rate may be affecting the population over time. 
Previously published Red List assessments:
2006 Least Concern (LC)

Geographic Range [top]

Range Description: Round Stingray ranges from Humboldt Bay in northern California to Panama in Central America, but appears to be most common between southern California and Baja California (Babel 1967, Nordell 1994, Lowe et al. 2007). Individuals identified as this species from Central America should be examined carefully as the genus is poorly known in this region.
Countries occurrence:
Costa Rica; El Salvador; Guatemala; Honduras; Mexico; Nicaragua; Panama; United States (California)
FAO Marine Fishing Areas:
Pacific – eastern central; Pacific – northeast
Lower depth limit (metres): 91
Upper depth limit (metres): 15
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Information on population abundance for the Round Stingray is only known for southern California, where they are highly abundant. Because this species is large and mobile (Lowe et al. 2007), abundance in southern California can be seasonally variable, with the highest catch-per-unit-effort (CPUE) of the Round Stingray occurring in the summer and fall off Long Beach (Hoisington and Lowe 2005, Lowe et al. 2007, Hale and Lowe 2008). Yet in other areas, such as San Diego Bay, abundance is stable year-round (Allen et al. 2002). A mark-recapture study conducted over three years (2000-2002) off Long Beach in southern California suggest that the population fluctuates seasonally, yet overall is stable or increasing (Lowe et al. 2007). 
Artisanal gillnet and trawl fishing communities in the Gulf of California encountered this species during surveys conducted  along the coast of Sonora, Mexico in 1998 and 1999 (a total of 42 individuals, Bizzarro et al. 2009a). Only two individuals were encountered during artisanal fishing community surveys along the Pacific coast of Baja California Sur, Mexico (Ramirez-Amaro et al. 2013), and along the Gulf of California coast of Baja California Sur, Mexico (Bizzarro et al. 2009b). 
In contrast, the Round Stingray was the dominant bycatch species of industrial shrimp trawl fisheries in the Gulf of California (including Sonora, Sinaloa, and Nayarit provinces; fisheries operating at depths of 9-90 m) in a 2004-2005 fisheries-dependent study (Morales-Azpeitia et al. 2013) and a 2004-2007 fisheries-dependent study (Rábago-Quiroz et al. 2012). Exploitation rates for the Round Stingray exceeded biological reference points (Jensen's and Pauly's exploitation rates were calculated to 0.77 and 0.84, respectively), suggesting that this species may be overexploited (Morales-Azpeitia et al. 2013). However, no population trend could be established. 
No information exists on population abundance and trends for the Round Stingray in Central America.
Current Population Trend: Stable
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:

The Round Stingray is a benthic warm-temperate to tropical round stingray usually found in nearshore waters < 15 m deep, but may occur down to 91 m depth (McEachran and Notarbartolo di Sciara 1995, Ebert 2003). These stingrays prefer soft bottoms composed of mud or sand, often in areas where eelgrass (used for camouflage) is quite abundant. Water temperature plays an important role in the distribution of these stingrays since they prefer temperatures above a minimum of 10°C (Ebert 2003, Jirik and Lowe 2012).

This species has a annual reproductive cycle with two litters of 1 to 6 pups (on average 2 to 3) following a short gestation period of three months (Babel 1967, Ebert 2003, Mull et al. 2010). Litter sizes range from 1 to 11 pups (Lyons and Lowe 2013), but average 2 to 3 pups (Ebert 2003). Size at birth is 6-8 cm Disc Width (DW; Babel 1967). Size at maturity is estimated to be 15.0 cm DW in females and 15.0 cm DW in males. Age at maturity is estimated to be 3.5 years (both male and female; Hale and Lowe 2008), while average reproductive age is 7-10 years (Hale and Lowe 2008). Maximum recorded size is 33.3 cm DW (Lyons and Lowe 2013), and longevity is estimated to be 14 years (Hale and Lowe 2008). Generation length is estimated to be 8.9 years (Hale and Lowe 2008).

Systems: Marine

Use and Trade [top]

Use and Trade: This species is not known to be utilized.

Threats [top]

Major Threat(s):

This species is not targeted commercially, but is taken incidentally by commercial shrimp trawl fisheries, recreational fishers, and artisanal gillnet fisheries. This species is generally discarded, but before being returned to sea, the tail is commonly severed, which may lead to increased levels of bycatch mortality. In Mexico, artisanal or commercial fisheries do not typically utilize urobatid rays as their small size generally precludes their sale as a food item for market purposes (Cartamil et al. 2011).

Conservation Actions [top]

Conservation Actions:

There are no species-specific conservation measures in place.

In México, a moratorium on the allocation of additional elasmobranch fishing permits was enacted in 1993, but no formal management plan has been implemented for the Round Stingray specifically or most other chondrichthyans in México. However, legislation is being developed in México to establish national elasmobranch fishery management. Currently, elasmobranch landings in México are poorly monitored and lack species-specific details. All batoids are generally broadly termed “manta raya”. Improved clarity in catch records would provide an essential basis for detecting fishery trends and are needed throughout the species’ range. Expanded monitoring of directed elasmobranch catches and bycatch in México are necessary to provide valuable information on the population status of these rays. Fishery-independent surveys of this and other demersal elasmobranchs are also necessary to provide estimates of abundance and biomass.

The development and implementation of management plans (national and/or regional e.g., under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and sustainable management of all chondrichthyan species in the United States and Mexico. Mexico implemented a National Plan of Action (NPOA) in 2004, and began reporting some species-specific data to the Food and Agriculture Organization of the United Nations (FAO). However, only 10% of catches were reported to species level in 2010, with most being grouped by order and above. The United States implemented a NPOA in 2001, with 25% of catches being reported to species level (Fischer et al. 2012). 

In Californian waters, a network of 29 marine protected areas (MPAs) were implemented in 2007 under California's Marine Life Protection Act, representing approximately 204 square miles (~18%) of state waters in the central coast region (California Department of Fish and Wildlife 2015). Due to these MPAs, most trawlers are restricted to operating in deeper waters, and only in central and northern California. As a result, fishing effort in the California trawl fishery has been reduced, and catches of this species have also likely been reduced (D. Ebert pers. obs. 2007). The California Department of Fish collects annual data on commercial fishery landings, however this species is lumped under the general category of "stingray" (California Department of Fish and Wildlife 2000-2015).

Citation: Lyons, K., Ebert, D.A. & Lowe, C.G. 2015. Urobatis halleri. The IUCN Red List of Threatened Species 2015: e.T60108A80677446. . Downloaded on 01 December 2015.
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