It’s a beautiful mid-May day on Tampa Bay, off St. Petersburg, perfect for sailing, suntanning, and sharks. Especially sharks, and in this case a blacktip shark, which is exactly what New College of Florida professor Jayne Gardiner has her hands full with – quite literally – at this moment.
The year-old shark wiggles in the grasp of Gardiner and a student, unaware that it is part of an effort to help its species thrive.
The professor and her students are part of a consortium of labs around the Gulf of Mexico studying shark nursery grounds. The New College team fishes in Sarasota Bay and Tampa Bay, determining which species are found in what areas, and how that relates to the marine environment.
Gardiner quickly places the shark into a holding tank so it can recover. Then the team quickly brings it out for an examination: They note the species and gender, weigh and measure the shark, and tag it with a numbered dart tag, inserted into the musculature at the base of the dorsal fin. Within a few minutes, the shark is back in the water and swims off. “We record the location where each fish was caught, so if a fisherman later catches a tagged animal, we can get an idea of where these animals go and how quickly they grow,” Gardiner said.
They also note the location and conditions including water temperature, salinity and dissolved oxygen, visibility, and the type of seafloor structure – mud, sand, rock or seagrass. As they fish, they are looking in particular for areas that have relatively higher numbers of newborn or juvenile animals. The project, headed by the NOAA Panama City Lab, is called the Gulf of Mexico Shark Pupping and Nursery Areas project, or GULFSPAN.
“Accurate knowledge of these areas is critical for successful management of fishery stocks and conservation efforts,” Gardiner said Shark science, and other areas of marine biology, go on year-round at New College. Sandra Gilchrist, director of the college’s Pritzker Marine Biology Research Center, has long-running projects on the behavior of hermit crabs.
And her students have pursued a number of projects, involving both animals and plants, relevant to the Gulf Coast marine environment. Pollution in lakes and the Gulf of Mexico, and its effects on marine life and migratory birds is a growing concern. Gilchrist’s students examined the efficacy of common wetlands plants — blue flag iris, Muhley grass, yellow canna and black needlerush — and how they function in tandem to reduce stormwater pollution.
They found that while the blue flag iris provides color and wildlife attraction to remediation sites, it is not as effective as yellow canna in uptake and sequestration of pollutants.
Restoring seagrass is an essential component of restoring life to Florida bays. Gilchrist’s students tested ways to increase the success of seagrass restoration projects. Seagrasses are sensitive to siltation from construction projects and to degradation from propeller scars. The students used pre-planted mats of coconut fiber matting, which degrades over time, to keep the newly planted seagrass in place. The matting was most effective in decreasing the in-fill time in areas with large scars to close the gaps more quickly.
Another project looked at one impact of the most common activity on Florida’s beaches: How sounds, such as those generated from foot traffic on beaches, affect burrowing behaviors of crustaceans such as fiddler crabs that perform many ecological services. Consistent vibrations, Gilchrist said, cause fiddler crabs to recede back to a burrow with consistent vibration, affecting their feeding and social interactions at low tide.
However, when the vibration ceases, they will return to the activities, but remain closer to burrow entrances.
And there is still more with sharks. In January, New College students Charlie Edelson and Lisa Crawford worked at Sarasota’s Mote Marine Laboratory examining the sensitivity of the electrosensory systems of adult sandbar sharks.
To test the sharks’ perceptiveness, the students created a weak electric field in the Mote lab tank. The sharks typically respond to the field by turning toward the electrodes, on an acrylic plate, and biting at them. Because the electric field weakens over distance, the students could look at the position where the sharks first orient themselves toward the electrodes to calculate the strength of the field and minimum current that will get the sharks to respond.
They found that the larger sharks are extremely sensitive to weak electric fields, which means that they can potentially detect prey from a greater distance than smaller animals. This has both academic relevance – helping us understand how sharks locate prey, especially in murky water – and commercial importance, perhaps guiding better design of fishing gear that would reduce accidental catching of sharks, a big problem in Florida’s grouper and snapper fishing industry, Gardiner said.
The students’ work is receiving notice. Edelson and Crawford presented their research at the American Fisheries Society meeting in Portland, Oregon. Gilchrist’s student Robert Manley has been researching the behavior of mantis shrimp — better known as “snapping shrimp,” or, more infamously, as “thumb-splitter” by divers who have gotten too close. Mantis shrimp can shatter crab shells — or human thumbs — with their claws, that strike as fast as bullets and generate a shock wave in the water.
They also have complex eyes, capable of seeing in the ultraviolet range. Manley monitored the mantis shrimp under infrared light, testing how the light affected activity including courtship, hunting, predator avoidance and lair construction.He presented his work at the Society of Comparative and Integrative Biology last year.
Another Gilchrist student, Abigail Oakes, did her senior thesis on a an offshoot of her marine biology studies. Oakes, an avid sailor, worked with groups of high school students to measure the effectiveness of using the science of sailing to reinforce STEM education.
Education and outreach has been central to marine biology at New College. Gilchrist also runs PUSH/SUCCESS, a summer program that brings middle- and high-school students, from demographics under-represented in science, to the College for a two-week introduction to college-style research, lab work, report writing and presentation. It’s aimed at encouraging them to pursue medicine and science for further study and a career. The program, entering its 13th year, has nearly 200 graduates to date.
Marine biology students are a large contingent of the roughly 20 percent of New College students who graduate with a major in STEM fields. One of the most recent is 2015 graduate Melissa Marquez, who came to New College from Miami.
As a girl, she says, she was fascinated with misunderstood predators, and sharks are the most misunderstood of all. So as a college student, Marquez has spent virtually every summer and vacation studying sharks. She participated in tagging missions in the Bahamas and off South Africa, collecting research that became her senior thesis on the habitat use and migration of 34 great white sharks, examining factors including magnetic fields and fish populations.
Along the way, she founded her own non-profit, Sarasota Fins, to do educational programs in local schools. The website offers teachers bilingual infographics on sharks and the children’s books Marquez has written about the creatures.
Marquez, just returned from a conference in England, is headed to graduate school at for a master’s degree in marine biology at the Victoria University of Wellington in Wellington, New Zealand. She says the research-oriented faculty and program at New College is the reason for her achievement. “Had I gone anywhere else, I wouldn’t have been able to volunteer at Bimini’s Biological Field Station just after my first semester of college,” she said.
“Instead of my advisers meeting my internship in South Africa with skepticism, they embraced it, wished me luck, and provided me resources to study and use. The unique school encouraged my unique love.”