University of Miami researchers Dr. Neil Hammerschlag, right, and Ph.D. student Austin Gallagher, center, with a massive female bull shark in the Florida Keys. Her blood was sampled for stress prior to release. (Emma Smith photo)
Florida Sea Grant is contributing to Florida’s reputation as a leader in the conservation and management of sharks. In January, a new Florida law went into effect that protects tiger sharks and three species of hammerheads from harvest in state waters.
“Florida waters are one of the final bastions for shark diversity in North America, yet these waters are also revered recreational fishing grounds for multiple species,” said Neil Hammerschlag, Florida Sea Grant research and research assistant professor of marine affairs and policy at the University of Miami Rosenstiel School of Marine and Atmospheric Science. “As such, there is a growing research interest in how non-harvest activities – like recreational catch-and-release fishing – may affect shark health in these critical feeding and nursery areas.”
Hammerschlag and Florida Sea Grant scholar Austin Gallagher assessed the impacts of catch-and-release fishing on sharks in a yearlong study. The scientists took blood samples and administered behavioral reflex tests on 81 sharks across five species that were caught and subjected to a range of fight times associated with recreational fishing activities.
A blacktip shark’s nictitating membrane reflex is tested via a 5ml water squirt, a rapid and cost-effective test that University of Miami researchers are developing to test shark vitality for catch-and-release fishing. (RJ Dunlap Marine Conservation Program photo)
In addition to determining which sharks are most sensitive to catch-and-release fishing, the scientists were able to recommend the best release tactics for each species and develop a new field test for determining shark stress. The test, which costs less than $1, involves using a syringe to squirt saltwater on a landed shark’s eye to determine if the shark is under stress. If the shark is under stress, the angler should return it to the water immediately. Hammerschlag and Gallagher’s release tactics and test are contributing to a new Florida Fish and Wildlife Conservation Commission educational campaign highlighting handling techniques that will increase the survival rates of sharks.
