What lies beneath is always a surprise to one Marine Biologist

Fishing can be considered a game of cat and mouse. You feel the rush when there is that tug on your line and cannot wait to see what is on the other end.

Now, imagine that feeling if you are a marine biologist on a shark tagging trip.

“The first ones are always one of the most special ones,” said Dr. Dan Abel, a marine biologist at Coastal Carolina University. “We never know what we are going to pull up when we set a long line. Or what we will see when we are on the way to set a long line.”

Abel,  who has more than 30 years of experience researching sharks, has been shark tagging in Winyah Bay for more than 15 years. He started the program to give his undergraduate and graduate students a chance to study Juvenile Sandbar sharks.

Abel says shark tagging allows researchers the chance to study the movements of these ocean predators and why they like to frequent certain waters over others. The sharks can have a tag placed near the shark’s dorsal fin, or they can have an acoustic telemeter inserted into the abdomen of the shark.

Acoustic telemeters are little pingers that ping every 60 to 90 seconds. For researchers to get information on where the shark is, it has to go by an acoustic receiver.

Abel says Winyah Bay is so diverse and offers many surprises every time they head out to fish.

“What’s always surprising to me is the diversity and abundance of sharks and the size range in such a small ecosystem,” said Abel. “Winyah Bay has a very large watershed. It drains 18-thousand square miles, but the bay itself is not that large for it to have that many sharks and rays inhabiting it.”

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Infographic made by Sharon Tutrone using Animaps.com

Think of Winyah Bay as a hunting ground, where it comes down to the survival of the fittest.

“We have learned there is a mix of sharks within the bay, and they tend to divide themselves so the small ones can find safety and the big ones can find plenty of prey and room to swim around,” said Abel.

So, what is the draw for the sharks?

“We have learned that most of the sharks like high salinity waters, so it’s an estuary,” said Abel.

 

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Students measure the salinity of the water in Winyah Bay.                                           Photo: Sharon Tutrone

Salinity is the amount of dissolved salts that are present in water. It is that salinity that Abel says plays a role in why sharks visit Winyah Bay.

“The sharks will divide themselves based on salinities. Most of the big sharks, the oceanic or the near coastal sharks like high salinities,” said Abel. “Some of the smaller life stages we see will move up the river, and that will protect them from the bigger sharks.”

Salinity levels in Winyah Bay fluctuate because it has four rivers dumping into it.

“When there is a lot of rain in the water shed, the fresh water coming out can be quite significant which can lower the salinities, and not many sharks can live in low salinities,” said Abel.

To follow Abel and his students on their shark tagging trips to Winyah Bay click on the Coastal Carolina Shark Research team page on Facebook.

 

 

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Sharks of Coastal South Carolina. Why is Winyah Bay such a popular spot for these ocean predators?

Many who live in Myrtle Beach have heard of Winyah Bay. It is where the Waccamaw, Pee Dee, Black and the Sampit River all drain into South Carolina.

But did you know it also makes for a great place to raise kids? Shark “kids” that is.

“Winyah Bay is a primary and secondary nursery. A primary nursery is where an animal will go and give birth, and a secondary nursery will be where that baby then grows up,” said Caroline Collatos, a graduate student in the marine science department at Coastal Carolina University.

Collatos believes that Winyah Bay is a secondary nursery for three different species of sharks.

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Baby Blacktip shark caught in   Winyah Bay. Shark was tagged and released.                                Photo: Sharon Tutrone

“The evidence we collected is showing us that this bay provides an area for these juveniles to grow up and hopefully become sexually reproductive and add to the population,” said Collatos.

Sharks move due to the change of season. Some sharks are more tolerant to colder or warmer temperatures which decide when they leave an area.

“Winyah Bay has both cold water and warm water species. In the winter we have two different species that use the bay. They are spiny dogfish and smooth dogfish sharks,” said Collatos. “In the summer, we have four species that use the bay frequently; the most dominant species is the Juvenile Sandbar shark.”

Collatos says a lot of juvenile sharks that grow up in Winyah Bay eventually move out to coastal areas. But they have also seen older sharks make their way into the bay as well.

“We also have a lot of older adult sharks that come into Winyah Bay to feed on smaller sharks or other prey,” said Collatos.

Sharks are not the only animal that heads to Winyah Bay to mate. Recently the CCU Shark research team caught a female stingray that had two males trying to mate with her as the team brought her in on the fishing line.

So why are the waters of Winyah Bay so attractive to sharks? It is a question Coastal Carolina marine biologists are hoping to answer through their tag and release program.

Dr. Dan Abel, a marine biologist with CCU, started the research program more than 15 years ago. He takes a group of undergraduate and graduate marine biology students out to Winyah Bay to study Juvenile Sandbar Sharks.

“One of our aims is to simply look at the demographics of shark populations,” said Abel. “What factors influence the presence and absence and the diversity of sharks in ecosystems.”

The process of tracking sharks is tedious and precise. Abel and his students bait 25 hooks on a line that is 150 meters long. The line has floats and anchors at both ends. Once the lines are in the water, they soak for 30-45 minutes. The students then hand pull the line in, hoping they have a shark on one of the hooks.

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Long lines are baited with Mackerel. Photo: Sharon Tutrone

 

“Acoustic telemeters are little pingers,” said Abel. “We make a two-inch incision in the abdomen and put a double A battery-sized instrument inside, sew it back up, and it will ping every 60 to 90 seconds. For us to get information on where the shark is, it has to go by an acoustic receiver. Fortunately, there’s a ray of receivers up and down the coast and worldwide.”

Acoustic tagging allows CCU students to track the movements of return visitors to Winyah Bay.

Besides the tagging trips to Winyah Bay, Dr. Abel takes his students every May to the Shark Lab in Bimini, which is located in the Bahamas. Abel says the students get an up close and personal look at the sharks and the stingrays. Abel says everything they learn in Bimini prepares them for their Winyah Bay tagging trips.

To learn more about the Coastal Carolina shark research team’s findings, click here.