Scientists try to understand stingray decline

| 22/07/2013

(CNS): With the continued decline in stingrays at Cayman’s premier tourist attraction, Stingray City, scientists from home and abroad are trying to understand what is causing the numbers to fall. Scientists from the Guy Harvey Research Institute (GHRI) and the Department of Environment were assisted in a recent survey and health check of the local population by veterinarians, Dr Tonya Clauss and Dr Alexa McDermott, and nutritionist Dr Lisa Hoopes, from the Georgia Aquarium. DoE Director Gina Ebanks-Petrie said she hopes the collaborative effort could continue as more needed to be learned about the unique population in the North sound and the impact of the Sandbar.

“There is an urgent need to better understand the impact of the feeding and human interaction taking place at the Sandbar and Stingray City on the overall health, reproduction and behaviour of the rays at these sites,” she said.

Although not an annual event, a census of the rays in the North Sound has been carried out since 2002, with the assistance of GHRI and others. This is the second year that the Georgia Aquarium has been involved in the assessment of rays in the North Sound, which includes analysing blood samples for indicators of health, stress, and nutritional status.

The recent decline in the number of stingrays at the Sandbar has made the census even more important. 181 rays were tagged between 2002-2003, 99 in 2008, 61 in January 2012, but only 57 rays were tagged in July 2012.

“These numbers indicate a threat to the continued viability of the Sandbar as a tourism attraction,” Dr Guy Harvey, founder of the GHRI, said. “We need to understand the reasons for the recent decline in numbers of rays at the Sandbar, and the data we collect will be used to inform management interventions for this extremely important economic resource for the Cayman Islands.”

The team also conducted health checks on the stingrays at Dolphin Discovery, which were released onto the Sandbar recently. Dr Clauss, who is the director of animal health at the Georgia Aquarium, said the checks completed on the stingrays at Dolphin Discovery indicate that they were healthy and ready for release back into the wild.

The return of the six captive rays as a result of an amendment to the law was particularly important, Ebanks-Petrie said, because five of them were male and census research has shown that the numbers of male rays have decreased even more than females.

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Category: Science and Nature

Comments (9)

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  1. Sucka Free Cayman says:

    "Stingrays missing" even Scooby Doo could solve this one??? Here are your CLUES Who had not one but six held captive at their facility????? Then head to Mexico Cancun stingray attraction Check their stingrays DNA to match it with our Sand Bar Stingrays DNA compare it Then Investigate which Hondurans own this Cancun Facility their ties to Cayman and which facility and who??? come on DOE aren't our stinrays that important to our tourism industry to warrant this or are you afraid like certain Media outlets to call an Ace and Ace or are you scared to death also of what or who you might find. This aspect is no mystery even the blind can see this is a bunch of BS!

  2. Whodatis says:

    I predict, as with everything else nowadays including the demise of the dung beetle, it will be blamed on anthropogenic global warming / climate change – or whatever is the current title of the farce.

  3. Anonymous says:

    I wonder if the thousands of gallons of leachate pouring into the North Sound on a daily basis from Mt. Trashmore has anything to do with it. 

  4. Anonymous says:

    Either they've been fed to the captive Dolphins or they've got enough sense to see that the natives aren't welcome in their own country and decided to leave before they got kicked out!

  5. Anonymous says:

    All they needed to do is release the dolphin discovery stingrays with a bottle of viagra in um. Stingray city declining population solved, easy!

  6. Anonymous says:

    There are certain groups/cultures of people on the island who eat stingrays. What better place to go get a sting ray than sting ray city? Once your boat pulls up they flock.

    In addition I’m sure there are sharks in the area that slip in and slip out of stingray city for a nice meal when the craving hits.

    I would guess those are the two biggest threats to the sting ray population.

  7. SSM345 says:

    Perhaps they were rolled over? Is there any way we can let them know that they can come back as the PPM is doing away with the Roll Over Policy?

  8. Hoping for better days says:

    Good thing we have Gina Ebanks. She has been looking out for our ecosystem for years and trying her best to ensure the preservation of our marine life etc. Keep up the good work Gina.

  9. Anonymous says:

    I am no expert, and just a village idiot, so I don't expect to have my opinion taken seriously but here is my humble observation.

    Sharks, although related to stingrays, do enjoy them as a snack. Thats a fact, according to Marine Biology, not me.

    So, if we continue to fatten these rays up by feeding them all day long on squid and conch aren't we making them less reliant on their natural ability to hunt, thereby eating less and remaining nimble and fast? Those of us who dive can tell you that there are sharks in them there waters to the north of the reef.

    I am sure they come in at night when the people are gone and the rays are doing their best to head to the reef for protection (after waiting around to make sure that there is no more free lunch to get).

    Simple, we upset the delicate balance in nature the equation changes.

    Perhaps regulating the times in which we feed these rays may help limit the buffet style that the sharks are currently enjoying.

    I remember very clearly, a few years ago when tiger sharkes were cruising that area in broad daylight. Oh how quickly we forget. Did we think if we killed those sharks that they wouldn't be replaced by others?