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My paper is about Southern stingrays, the type of stingrays found most commonly in the Atlantic Ocean, from New Jersey through the Gulf of Mexico and the Caribbean to Rio de Janeiro, Brazil. I will begin by discussing some of the basic species characteristics, including which family they belong to, their body shape, their habitat, and what they eat. I will then discuss their defense mechanism, what problems their sting can pose to humans, and treatment options. Finally, I will further explain their relationship to the larger marine environment and discuss the possible effects of tourist feeding.
I. Brief background on species characteristics
a. Class Chondrichthyes (cartilaginous fish) Ð in the same family as sharks, skates, and chimeras
b. Order Rajiformes
c. Diamond-shaped body with pointed edges, reaching up to seven feet from nose to tail
d. Light colored forehead spot with gray, brown, or green skin on back that is able to change based on surroundings and gray or white underside
e. Lives in shallow, inshore open water with sandy or muddy bottoms
f. Eats small fish, shrimp, crabs, clams, and worms
II. Stingray stings
a. Results in ~1500 ER visits in the US annually, which is more than any other marine vertebrate
b. Stinger is enclosed in a sheath on the tail that is equipped with 1-4 venomous spines
c. Contact with the stinger venom results in intense localized pain, and can also potentially result in salivation, nausea, vomiting, diarrhea, syncope, muscle cramps, fasciculations, dyspnea, cardiac dysrhythmias, hypotension, seizures, convulsions, and rarely, death.
d. Immersing the affecting area in hot water will eliminate or significantly decrease the pain, and antibiotics should be taken due to the puncture nature of the wound.
III. Affects of wildlife feeding
a. Deliberate and long-term feeding of any animal alters the natural behavior patterns and populations levels
b. Can result in dependency and promote inter-species aggression
c. However, also promotes awareness and appreciation of species
d. Feed stingrays are more likely to have lower body condition, be injured by boats and predators, be susceptible to ecto-dermal parasites, be engaged in intense interference competition (in the form of conspecific bite marks), and have a higher mean numbers of injuries, parasites, and median bite marks. By exploring alternative hypotheses to explain the pattern of our findings
e. Stingray City Sandbar is a warm, shallow area where Southern stingrays gather to be fed and has become a significant tourist attraction
f. Caymanian stakeholders are concerned this feeding has negative impacts
g. Fed rays have a fatty acid profile that more closely resembles the fatty acid profile of the tourist feed squid than non-fed rays.
h. This has the potential to have long-term negative impacts on the stingraysÕ growth, immune system, resistance to parasites and disease, and overall survival
i. Suggested to decrease the amount of artificial food or change the composition
j. Also suggests implementing management techniques to limit boat and stingray density in order to control crowded conditions at tourist sites and less negatively impact stingray survival
IV. Involvement with other marine animals
a. Symbiotic cleaning relationship with the bluehead wrasse
b. Rays were cleaned by swimming slowly around a cleaning station while the wrasses nipped at their dorsal side
c. Rays were also cleaned in a stationary position on when they settled on the cleaning station or surrounding area in a position termed the solicitation pose
d. An octopus has been observed to be attached to a stingrayÕs back
e. Reasons for this are unclear, but hypothesized as a means of travel for the octopus, a technique to avoid predation by the stingray, or for feeding on the stingrayÕs mucus
Works Cited
Clark, R. F., Girard, R. H., Rao, D., Ly, B. T., & Davis, D. P. (2007). Stingray envenomation: A retrospective review of clinical presentation and treatment in 119 cases. Journal of Emergency Medicine, 33(1), 33-37.
Gilliam, D., Sullivan, K. (1993). Diet and feeding of the southern stingray Dasyatis Americana in the central Bahamas. Bulletin of Marine Science 52(3), 1007-1013.
Orams, MB. (2002). Feeding wildlife as a tourism attraction: a review of issues and impacts. Tourism Management, 23, 281-293.
Rays (2008). In Lerner B., Lerner K.(Eds.), . Detroit: Thomson Gale.
Semeniuk, C.A.D., Rothley, K.D. (2008). Costs of group-living for a normally solitary forager: effects of provisioning tourism on southern stingrays Dasyatis americana. Marine Ecology Progress Series, 357:271-282.
Semeniuk, C.A.D., Speers-Roesch, B., Rothley, K.D. (2007). Using Fatty-Acid Profile Analysis as an Ecologic Indicator in the Management of Tourist Impacts on Marine Wildlife: A Case of Stingray-Feeding in the Caribbean. Environmental Management, 40(4), 665Ð677.
Snelson, F.F., Gruber, S.H., Murru, F.L, Schmid, T.H. (1990). Southern Stingray, Dasyatis americana: Host for a Symbiotic Cleaner Wrasse. Copeia, 4, 961-965.
Southern stingray. (n.d.). Retrieved April 28, 2009, from EBSCO Animals database.
Souza, A.T, Ilarri, M.I., Valentim, L.P.F (2007). Coral Reefs, 26:333.
Vijayasekaran, V.J. (2001). Stingray Envenomation or Iatrogenic Thermal Burn. ANZ Journal of Surgery, 71, 323Ð325.
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