Two College of Charleston marine biology graduates have recorded the oldest known bonnethead shark in the nation as part of the COASTSPAN shark survey conducted by the South Carolina Department of Natural Resources (SCDNR). Bryan Frazier ’00 (and current Master of Environmental Studies candidate) and David Shiffman ’11 (M.S.) determined through the direct aging process that this shark was at least 17 years old. Previously, the oldest direct aged bonnethead was captured in the Gulf of Mexico at age seven.
Frazier is a SCDNR marine biologist and Shiffman is a SCDNR hourly field assistant. Frazier helped capture this particular shark for the first time in 2002, just after the COASTSPAN shark survey was started (1998). It was also captured in 2006 and only grew 27mm (1.1 inch) in the 9 years between initial tagging and the most recent recapture (2011).
“It is the long-term nature of this program that has allowed us to continue to contribute to the biological knowledge about these species,” Frazier says. “In addition to the long-term recapture of the bonnethead, we have also recaptured the oldest aged Atlantic sharpnose shark (at least 16 years old), and the oldest aged blacknose shark (at least 21 years old). All were recognized due to the fact they had been captured and tagged years ago. Having this information about how long they live allows SCDNR and the National Marine Fisheries Service (NMFS) to properly manage these species – as they are often overfished.”
Bonnetheads are a member of the hammerhead shark family (Sphyrnidae). They are classified as small coastal sharks, and are common to the Southeastern United States and Gulf of Mexico. They are summertime residents of South Carolina’s estuaries, entering the waters in April and May and leaving when water temperatures cool in the fall. They grow to as large as 4 feet, and once mature, they reproduce annually.
Shiffman says, “It’s amazing that even with a species of shark as commonly seen as the bonnethead, there are exciting new discoveries being made all the time. We know that sharks are extremely important to our oceans, and we know that many species are declining in population around the world at alarming rates, but there’s still so much more to learn!”
Shiffman’s thesis for the Master’s in Marine Biology focused on another local shark species, the sandbar shark, and it’s feeding ecology. Frazier’s thesis for the Master of Environmental Studies program is focused on the age and growth of the bonnethead.
He says, “My undergraduate experience at the College of Charleston gave me the base knowledge to go into my chosen field of marine biology. My Master’s in Environmental Studies will allow me to further my career while pursuing more challenging questions in my field as well as allowing me to mentor other students who are interested in the marine sciences.”
Shiffman will continue his study of shark ecology and conservation at the University of Miami while he earns his Ph.D. He writes about sharks for the marine biology blog SouthernFriedScience.com, and tweet about sharks @WhySharksMatter.
The Cooperative Atlantic States Shark Pupping and Nursery Habitat Survey (COASTSPAN) is funded by the National Marine Fisheries Service and data generated by this project supports better stewardship of our coastal sharks. The primary sharks found in South Carolina’s coastal waters are the Atlantic sharpnose, the sandbar, the bonnethead, the blacktip, the finetooth, and the scalloped hammerhead. The blacknose, spinner, the bull and the lemon shark are also observed to a lesser degree.
The Master of Environmental Studies (MES) Program at the College of Charleston provides students with an interdisciplinary foundation, allowing them to take a holistic view of environmental problems and potential solutions through coursework and research in environmental policy and science.