Species Spotlight: Whitespotted Eagle Ray

Photo Credit: John Norton

Common name: Whitespotted Eagle Ray, Bonnetray 

Scientific name: Aetobatus Narinari 

Range: Western Central and Southwest Atlantic Ocean; recently extended to the Eastern Atlantic Ocean

Conservation status: Endangered on the IUCN Red List; currently protected in Florida state waters 

INFORMATION 

The Whitespotted Eagle Ray (Aetobatus Narinari) is a very large ray that can reach a maximum wingspan of 10 feet, a total length of 17 feet, and weight of 500 pounds. (Florida Fish and Wildlife Conservation Commission). The Whitespotted Eagle Ray is distributed throughout the Atlantic Ocean. According to the IUCN, in the west, it ranges from Cape Hatteras, United States of America to Rio de Janeiro, Brazil, including the Gulf of Mexico and the Caribbean Sea, and in the east, it ranges from Mauritania to Angola, and possibly South Africa. This species commonly inhabits shallow waters closer to shore such as estuaries, lagoons, and bays, but is also found in coral reef ecosystems up to a 200 foot depth. (IUCN 2020). This species is a live-bearing species with a low regeneration rate. It has a one-year gestation period and births between 1-4 pups a year. (Kyne et al. 2006). 

This species is considered a hard-prey specialist as they consume hard-shelled prey such as bivalves, gastropods, and large crustaceans by crushing their exoskeletons. (Ajemian et al. 2012, Serrano-Flores et al. 2018). They also serve as an important food source for top predators like sharks, making them a key part of the intermediate trophic level and an important part of the food web as both predator and prey. (Barnett et al. 2010). 

THREATS AND CONSERVATION 

The Whitespotted Eagle Ray is intrinsically sensitive to anthropogenic threats, such as fishing pressures, due to its low regeneration rate, slow growth, and late maturity. (Frisk et al. 2005). This species is particularly vulnerable to fishing pressures as its swimming behavior makes it susceptible to a range of fishing gear throughout the water column. (IUCN 2020). Even modest fishing pressure is enough to result in significant population declines. (Ferretti et al. 2010). But fishing pressure is high throughout their range as they are commonly caught in target artisanal gillnet fisheries and industrial shrimp trawl fisheries as bycatch. (IUCN 2020). As a result, scientists estimate that the Whitespotted Eagle Ray population has undergone a reduction of 50–79% over the past 30 years due to these compounding pressures. 

While fishing pressure is a major concern, habitat loss, public perception of stingrays, water quality, and climate change are also believed to be driving the species to extinction (Dulvy et al. 2014). Because this species routinely enters estuaries and occurs close to shore, they are also threatened by pollution, dredging, and habitat loss. (Dulvy et al. 2014). This species is also a popular aquarium species and is captured for use in aquarium displays (Swider et al. 2017). 

In light of concerns over the conservation of Whitespotted Eagle Rays and other shore-based shark and the important role it plays in the ecosystem, the state of Florida has prohibited the harvest, possession, purchase, sale or exchange of this species (Florida Administrative Code 2020). However, enhanced legal and regulatory protections at the national and international levels are urgently needed to protect its wild population from further decline. Additional research on the species should also be prioritized in order to develop sound, science-based conservation measures. 

REFERENCES 

1. “Eagle Rays: Spotted Eagle Ray.” Florida Fish And Wildlife Conservation Commission, myfwc.com/research/saltwater/sharks-rays/ray-species/spotted-eagle-ray/. 

2. (SENAI-Paraná), Patricia Charvet, et al. “The IUCN Red List of Threatened Species.” IUCN Red List of Threatened Species, 28 July 2020, www.iucnredlist.org/species/42564343/2924463.

3. Kyne PM, Ishihara H, Dudley SFJ, White WT (2006) Aetobatus narinari. In: IUCN 2013. IUCNRed List of Threatened Species. Version 2017.1. www.iucnredlist.org. 

4. Ajemian, M. J., Powers, S. P., & Murdoch, T. J. T. (2012). Estimating the potential impacts of large mesopredators on benthic resources: Integrative assessment of spotted eagle ray foraging ecology in Bermuda. PLoS ONE, 7(7). https://doi.org/10.1371/journal.pone.0040227 

5. Serrano-Flores, F., Pérez-Jiménez, J. C., Méndez-Loeza, I., Bassos-Hull, K., & Ajemian, M. J. (2018). Comparison between the feeding habits of spotted eagle ray (Aetobatus narinari) and their potential prey in the southern Gulf of Mexico. Journal of the Marine Biological Association of the United Kingdom, (1953), 1–12. https://doi.org/10.1017/S0025315418000450 

6. Barnett, A., brantes, K., Stevens, J. D., Yick, J. L., Frusher, S. D., & Semmens, J. M. (2010). Predator-prey relationships and foraging ecology of a marine apex predator with a wide temperate distribution. Marine Ecology Progress Series, 416, 189–200. https://doi.org/10.3354/meps08778 

7. Frisk, M. G., Miller, T. J., & Dulvy, N. K. (2005). Life histories and vulnerability to exploitation of elasmobranchs: Inferences from elasticity, perturbation and phylogenetic analyses. Journal of Northwest Atlantic Fishery Science, 35, 27–45. https://doi.org/10.2960/J.v35.m514 

8. Ferretti, F., Worm, B., Britten, G. L., Heithaus, M. R., & Lotze, H. K. (2010). Patterns and ecosystem consequences of shark declines in the ocean. Ecology Letters, 13(8), 1055–1071. https://doi.org/10.1111/j.1461-0248.2010.01489.x 

9. Dulvy, N. K., Fowler, S. L., Musick, J. A., Cavanagh, R. D., Kyne, P. M., Harrison, L. R., … White, W. T. (2014). Extinction risk and conservation of the world’s sharks and rays. eLife, 3, e00590. https://doi.org/10.7554/eLife.00590 

10. Swider, D.A., Corwin, A.L., Kamerman, T.Y., Zimmerman, S.L., Violetta, G.C., Davis, J. and Janse, M. 2017. Reproduction of spotted eagle rays, Aetobatus narinari, in aquaria. Elasmobranch husbandry manual II: Recent advances in the care of sharks, rays and their relatives. Elasmobranch husbandry manual II: Recent advances in the care of sharks, rays and their relatives, pp. 433–442. 

11. “Florida Administrative Code.” 68B-44.004 : Bag and Vessel Limits Applicable to Florida Waters; Restrictions on Possession of PROHIBITED Species; Transit Through Florida Waters - FLORIDA ADMINISTRATIVE RULES, Law, Code, Register - FAC, FAR, ERULEMAKING, www.flrules.org/gateway/RuleNo.asp?title=SHARKS+AND+RAYS&ID=68B-44.004.

12. Kyne PM, Ishihara H, Dudley SFJ, White WT (2006) Aetobatus narinari. In: IUCN 2013. IUCNRed List of Threatened Species. Version 2017.1. www.iucnredlist.org.