Featured Species: Southern Stingray (Hypanus americanus)

Happy New Year everyone! I decided to start off 2019 with one of my favorite flat sharks: the Southern Stingray (Hypanus americanus,formerly Dasyatis americana) (Klimley, 2013). The southern stingray is a fairly common ray throughout the temperate and tropical waters of the Western Atlantic, ranging from New Jersey all the way to Brazil (Tricas et al., 1997).  They are known for their wide bodies, reaching as much as 5 feet (1.5 m) across, and large spiracles which are often mistaken for eyes when buried in the sand. Their tail also has a long fold of skin with a low keel just below a series of sharp, dagger-like spines which can be as sharp as a butcher’s knife and are capable of delivering venom to their victim (Tricas et al, 1997).

Dasyatis americana 2
Flannery, A. (Photographer). (2016 May). Southern Stingray Emerging from the Sand in the Bahamas [Digital Image]. Original Content.

The southern stingray, like most rays, are a bottom dwelling species. They prefer sandy substrates just off beaches, lagoons, and sea grass beds where they can rest during the day (Tricas et al., 1997). At night, they become active hunters on coral reefs and sea grass beds. They rely on their keen senses to seek out small bony reef fishes and invertebrates like crabs, shrimps, and even worms, which they crush with their plate-like teeth.

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Flannery, A. (Photographer). (2016 May). Southern Stingray Flying Over a Reef in the Bahamas [Digital Image]. Original Content.

Stingrays typically use two methods of locomotion: Oscillatory and Undulatory (Klimley, 2013). Oscillatory locomotion is utilized by the cownose rays (Rhinoptera bonasus). They flap their pectoral fins up and down with the posterior edge of their fins lagging behind. This pushes water backward, pushing them forward (Klimley, 2013). Undulatory locomotion is utilized by the southern rays. They send a propulsive wave down the length of their elongated pectoral fins. This forces water backward and propels them forward (Klimley, 2013).

 

Earthly Video (Videographer). (2013 April 28). Southern Stingrays Swimming, Shark Ray Alley, Belize [Video Clip]. Retrieved from https://www.youtube.com/

 

If you’ve ever visited the Atlantic coast you’ve probably heard of the “Stingray Shuffle.” If you haven’t heard of the Stingray Shuffle, it’s where you enter the ocean but shuffling your feet through the sand rather than picking up your feet. The idea is to gently nudge a stingray out of its hiding place rather than very rudely introduce yourself to a hiding ray by stepping on its back, and getting stuck by a very sharp barb in the process!! OUCH! This is an excellent method to use regardless of where you are in the world because rays are excellent at burying themselves in the sand, mud, and just about every other substrate! Southern stingrays love sandy substrates. Their large spiracles allow them to completely bury their large bodies beneath the white sand and continue to pump oxygenated water over and across their gills, which are underneath them (Tricas et al, 1997; Klimley, 2013).

 

 

Scott Knobler (Videographer). (2013 September 23). Southern Stingray Buries Itself [Video Clip]. Retrieved from https://www.youtube.com/

 

In May of 2016, I spend 9 days in the Exumas, Bahamas on the Shedd Aquarium’s R/V Coral Reef II. Each morning, I would step out onto the stern in the morning and would see these dark circles gliding and hovering in the water. It was surreal watching all these southern rays from the surface. Over the 9 days, I lost track of the number of southern rays I encountered. Despite their apparently abundant numbers, this species is considered Data Deficient by the International Union for Conservation of Nature (IUCN).  There is no fishery that directly targets the southern rays, and while they are sometimes taken as bycatch, most populations, like those in the United States and the Bahamas, appear to be healthy (Grubbs, Snelson, Piercy, Rose & Furtado, 2016). However, there is little information about the current population trends and the impacts of ecotourism in certain areas where swimming and interacting with these animals on a regular basis, like the Cayman Islands, has become increasingly popular (Grubbs et al., 2016). Further information is required to reach an assessment for the southern stingray.

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Flannery, A. (Photographer). (2016 May). Southern Stingrays from the Surface in the Exumas [Digital Image].

Rays Stats

Authority: Hildebrand & Schroeder, 1928

Family: Dasyatidae; 102 species

Length: 5 feet (1.5 m) disc width

Weight: 160 lbs (72.5 kg)

Habitat: Sandy bottom substrates off beaches, lagoons, and sea grass beds

Depth: Surface to 174 feet (53 m)

Reproduction: Ovoviparous

Gestation: 3 – 4 months

Litter Range: 2 – 10 pups

Home Range: Central western Atlantic in temperate to tropical waters; from New Jersey coast to Brazil

Diet: Decapod crustaceans are most common prey items, other items include invertebrates, and bottom dwelling fishes

IUCN Status: Data Deficient

(Tricas et al., 1997; Klimley, 2013; Grubbs et al., 2016)

Thanks so much for checking out the Southern Stingray! If you missed last week’s featured species, please be sure to check out the Pondicherry Shark. If there is a species of shark you’d love to know more about, leave me a comment or send me a message! I would love to do a feature on your favorite species.

I have exciting news! My children’s book Winifred the Wondrous Whale Shark is now available on Amazon. Check it out! And don’t forget about the Shark Spot. Proceeds are donated to Project AWARE.

The new Ocean For Sharks Shop is open! There’s handmade ocean inspired plush animals, canvas paintings, and of course my children’s book, Winifred the Wondrous Whale Shark, available in print and PDF. Be sure to stop by. Remember proceeds benefit shark research and conservation with a donation to Project AWARE!

Conservation legislation needs public support in order to become law and help protect the environment and wildlife. Tell your representatives that you care about environmental and wildlife conservation.  It only takes a moment to make a change that will last a lifetime. Until next time finactics!

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Featured Image Source

Peters, B. (Photographer). (1992 February). Southern stingrays (Dasyatis americana) at Stingray City [Digital Image]. Retrieved from https://commons.wikimedia.org/wiki/File:Southern_stingrays_at_stingray_city.jpg

Literature Cited

Grubbs, R.D., Snelson, F.F., Piercy, A., Rosa, R. & Furtado, M. (2016). Hypanus americanusThe IUCN Red List of Threatened Species. Retrieved from https://www.iucnredlist.org/species/60149/104123038

Klimley, A. P. (2013). The biology of sharks and rays. University of Chicago Press.

Tricas, T. C., Deacon, K., Last, P., McCosker, J. E., Walker, T. I., & Taylor, L. (1997). The Nature Company Guides: Sharks and Rays. (L. Taylor, Ed.). Hong Kong: The Nature Company, Time Life Books.

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