Shark Tagging with MAST Academy

By Grace Roskar, SRC Intern

On the overcast morning of November 15^th, the SRC team, the Diver’s Paradise captain and crew, and students of MAST Academy gathered at Crandon Marina to brave wind, clouds, and light rain to embark on a day of shark tagging. MAST Academy is one of our oldest participating school groups and although the weather was not the typical Miami sunshine, the students were eager to board the boat and get underway. We motored out through choppy waters to the Safety Valve in Biscayne Bay, which is a group of shallow sand flats that is intersected by the tides flowing in and out. After some quick introductions and a briefing on the process of deploying drumlines, the equipment was set out and allowed to soak for an hour. In the meantime, trip leader Christian Pankow demonstrated the process of working up the sharks to the MAST students. When an hour had passed, we set out to retrieve the first set of ten drumlines. To no avail, there were not any sharks on the first ten lines, so they were set back in the water after being reloaded with fresh pieces of bait. However, several of the hooks came up with the chunk of barracuda steak missing and two lines had bite marks and shredding on the tough monofilament line, so it seemed that sharks could be somewhere close. The second set of ten drumlines was pulled up and again, no sharks. They were set back into the water and were allowed to soak a little bit longer.

A MAST Academy student tosses the barracuda bait into the water.

On the 21^st line, a blacktip had been hooked! To avoid setting up the platform in such rough seas, the 1.64 meter male shark was brought directly onto the stern of the boat by Christian and grad student Robbie. Once secured, MAST students assisted the SRC team with several length measurements, taking a sample of the dorsal fin, and inserting a dart tag into the shark’s dorsal fin. The shark was swiftly released back into the water in great condition. Since time allowed, a fourth set of drumlines was deployed, bringing our total to 40 drumlines for the day. Another blacktip, slightly smaller at 1.53 meters, was pulled up and worked up via the same process on the back of the boat. Students were able to assist in the work-up process again and also touch the shark, feeling the unique texture of their dermal denticles. Another line later had a nurse shark on the hook, but just as Christian and Robbie were pulling it up to secure it onto the boat, it simply spit the hook out of its mouth and swam off! Although it was disappointing to be so close to pulling in our third shark of the day, Christian was able to estimate it at 1.5 meters in length and the students were glad to still be able to see the day’s second shark species at the surface of the water.

A student helps test the reflex of the shark’s ‘eyelid,’ or nictitating membrane, to measure the shark’s stress level.

A student helps measure the total length of the shark.

For the remainder of the trip, Christian dissected a barracuda eye as a demonstration for the students, and the SRC fish traps that had been deployed at the beginning of the trip were pulled up. The fish in the traps, including two filefish, were measured and photographed for the SRC’s ongoing study of fish populations associated with shark populations in the area. Although the weather was a bit less pleasant than we’re used to, it was still a great day out on the water with MAST Academy. For some students, it was their first time seeing sharks, and the whole group seemed pleased and more knowledgeable about these important apex predators after the day was over. The SRC team was able to gain valuable data from the two blacktip sharks and we hope to have MAST Academy back out with us soon!

Thank you MAST Academy for joining us for a day of shark tagging!