Caroline (from over at CCU Shark Research Team) stopped by the Fish Thinkers blog to give us a run down on where her research is headed and a sneak peak into the world of grad student shark research in the United States.
Hello, Caroline here from the CCU Shark Research Team! I am a current graduate student at Coastal Carolina University (CCU) where I study the local coastal shark species. Before I get into the shark stuff here is a tiny bit about our location- CCU is located in Conway, South Carolina, which is an hour away ftom Winyah Bay, the 4th largest estuary on the US east coast when classified by discharge rate. Winyah Bay is a mixed estuary with river systems feeding into the bay and ocean tides flowing and ebbing into the bay. Depending on the tide and location within the bay, the water can range from fresh water to ocean water.
Ok phew! Now what we all want to hear about- sharks!!!
Working with Professor Dan Abel, the first person to describe the shark populations in Winyah Bay, I hope to better describe the demographics of the current shark population in Winyah bay. I plan to compare current shark populations in the bay to previous surveys, as well as published literature. With the use of longline surveys and acoustic telemetry, I also plan to better describe the preferred habitats of each species in the bay, the shark movements within Winyah Bay, and the specific abiotic factors influencing shark distributions. My top priority when working with these animals is to tag and release the animal in the fastest, least stressful way for the animal, even though sometimes it’s stressful for me! Through my research I do not want to impact the animals I am studying in any way, but simply perform “alien abductions” as I like to say, and then let them go about their regular life! Each of our sharks we catch gets outfitted with a tag from the NOAA Shark Tagging Program, is measured, sexed, IDed, and the hook is always removed before the animal is released healthy and active. We also take DNA and isotope samples, which we preserve for lab analysis.
In 2007 Professor Dan Abel published a scientific article describing the shark populations in the bay and the purposes for which they utilize the bay. Dr. Abel showed that the bay represents habitat and feeding grounds for 12 coastal species. The species present differ during the seasons due to the water temperature. Sharks inhabiting the bay are migratory, with Spiny Dogfish, and Smooth Dogfish, found during the colder months, and Sandbar, Blacktip, Spinner, Finetooth, Bull, Lemon, Scalloped Hammerhead, and Bonnethead sharks, found in the warmer spring and summer months. Atlantic Sharpnose sharks are the only species that are found year round. Abel also demonstrated that the bay may act as a primary and secondary nursery grounds for multiple coastal species including: Sandbar, Atlantic Sharpnose, and Finetooth sharks. The sharks we catch in the bay represent all sizes and age ranges, from young of year (less than a year old) to mature adults, and everything in between. Some of the smallest sharks we have caught are the young of year Atlantic Sharpnose with a total length of 40 cm! (Which is pretty small when we compare it to the 250 cm bulls and lemons we have caught).
Not only does Winyah Bay provide a valuable habitat to these shark species, but it also provides a home for a multitude of other aquatic and terrestrial species. Atlantic stingrays, Southern stingrays, Sturgeon, Red drums, Atlantic Bottlenose Dolphins, Bald eagles, Loggerhead Turtles, Star drum, Blue crabs, Flounder, Oyster toadfish, and a plethora of different jellyfish species and marsh birds all inhabit the bay. And that’s just a few! While we are on the water, we often see jumping sturgeon, pods of dolphins swimming by the boat, bald eagles perched in trees or flying above us, and an assortment of seagulls and marsh birds going about their daily routines. I have even seen an alligator or two right next to our dock!
Now for the fun part! Here’s a bit about my field research. Since May, I have caught and released over 100 sharks representing a total of 5 out of the 10 summer species! I have also deployed 5 acoustic transmitters so far. These special transmitters will constantly ping every 40 seconds with special ID codes that receivers detect when the transmitters are within a specific range of the receiver. Some of my transmitters also emit data regarding the temperature and depth of the water the shark is currently in. Since there are receivers placed throughout the bay, these transmitters will hopefully help me discover where the sharks are moving and in what temperature and depths they reside. My first acoustically tagged shark is a female Finetooth shark named Eugenie after Eugenie Clark, a personal idol and the ultimate “shark woman”.
We have had a fun time collecting data these past few months. Not only have we caught a ton of amazing sharks, but we also caught a HALF shark! Sharks preying on other sharks is not uncommon and can even start in the womb for some species, but that doesn’t make it any less cool to see an estimated 3 foot shark be cleanly bit in half from a much larger shark! This summer we have also caught a lot of young of year sharks, some with their umbilical scars still present! This is exciting for the nursery aspect of my research because it shows that newborn sharks are utilizing the area. I also caught a female Blacktip who had got tangled in what looked like a large gill net or trammel net. The net lines had cut into her body, gills, and underside so much that her skin had grown over the line (see photos below). She still had deep lacerations from the net when we caught her, even though she was on the road to recovery. When I removed the netting, I had to cut it into multiple areas and physically pull it OUT of her body. Keep in mind that we caught her most likely half way through her healing process so the original wounds must have been a lot worse. It makes you think about all the gear people have lost and is subsequently “ghost fishing” out there. In other news- not only did we also catch a 240 cm male Lemon shark this summer, but we also have received recapture data from the NOAA Shark Tagging Program from a local fisherman who caught and released one of the Sandbars we tagged! This data is extremely exciting not only because it shows sharks movements and growth sizes; but because it also shows that recreational fisherman are actively partaking in the tagging program and releasing tagged fish! If you see a tagged fish of any kind- Release it and Report it! As a researcher, I wish I could give everyone who reports and releases my tag info Thank You notes- but their information is all blocked for privacy reasons! Alas!
Through my research, I hope to contribute to overall species migration knowledge and help conserve shark populations through outreach and education. Sharks are truly amazing and wonderful creatures and we still have tons to learn about them! Thank you to everyone who took the time to read this, I hope you learned some things about what we do and appreciate sharks for the amazing creatures they are and not the mindless “maneaters” people portray them as.
A huge thank you to Fish Thinkers for reaching out to me, sharing some shark knowledge, and supporting the CCU Shark Research Team!!! We are always happy to collaborate with fellow researchers out there! If you are interested in checking out more of our research and adventures follow our Instagram and Facebook accounts.