Monday, August 1, 2011

Shark Week - World's Oldest Bonnethead Shark at the Tennessee Aquarium?


O.K. shark fans, an interesting story surfaced off the coast of South Carolina recently which leads to the Tennessee Aquarium. It's a tale that begins in the Florida Keys nearly a quarter of a century ago. That's when Rob Mottice was beginning his career with the - yet to be opened - Tennessee Aquarium. "We drove a box van, like a U-Haul truck to near Marathon, Florida to pick up some bonnethead sharks. This was back in 1991 several months before the Aquarium opened in May of 1992," said Mottice. "It was a long drive back to Chattanooga and the sharks did great." Mottice said that two of the bonnetheads were about the same length which often indicates the animals are "in the same class," or about the same age. "The female had pups at the Aquarium later which leads us to believe she was about two years old when she got here. And we think the male was about the same age."
 
The male bonnethead is still swimming around in the Aquarium's Gulf of Mexico exhibit. If Mottice's estimate is correct, then this shark is 20 to 22 years old.


Far from being "long in the tooth," this shark is still a feisty fish. When volunteers enter the water to feed the Aquarium's and other reef fish in this exhibit, this shark is ready to chomp down on meals like a pup. "You still want to be quick while feeding this guy," said Mottice. "He's very quick and will occasionally nip at fingers if a diver doesn't release food fast enough."

According to fishbase.org, the maximum reported age of bonnethead sharks in the wild is twelve years. So a few eyebrows were raised recently when a significantly older bonnethead shark was recaptured off the coast of South Carolina by the South Carolina Department of Natural Resources Coastal Shark Survey Team. When this particular shark was originally tagged in 2002, it was already a full-grown adult. Through Vertebrae Ring Analysis, the age of this shark was determined to be 17 years old. Southern Fried Science, a science and nature website, reported the tagged shark as being the “World's oldest known bonnethead shark.”

Bryan Frazier, a marine biologist with the South Carolina Department of Natural Resources, believes that while the tagged shark was well beyond the average life span of around 15 years, there may be older bonnetheads in the sea. Frazier thinks that under-aging occurs in age and growth work. “It’s only when we have a long-term recapture such as this one, and a few others I have gotten over the years, that we see that these animals are really living longer than we first thought,” said Frazier. “I imagine as time goes on we will continue to encounter individuals that expand our knowledge.”

So is the Tennessee Aquarium's shark the world's oldest bonnethead? As far as Mottice knows, this guy holds the longevity record for members of this species on public display. "Obviously animals like this get excellent care. They get hand delivered, restaurant-quality groceries, volunteer divers routinely clean their home and they have an excellent health plan with regular house calls from our veterinarian."

Visitors can enjoy watching this "Grand-Daddy" of bonnetheads during Shark Week along with epaulette sharks in Stingray Bay and the sand tiger and sandbar sharks in the Secret Reef exhibit.

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