Shark tagging with Grand Classroom Ohio

by Alison Enchelmaier, RJD student

On Thursday morning I drove to Crandon Marina, wide awake thanks to the full travel mug of coffee in the cup holder. No matter how many times I’ve been on the boat I’m excited, as every trip is a new and thrilling experience. That morning the whole team seemed to be full of energy as we loaded our gear on to the boat, excited for the trip ahead. At 9 am we were joined by our guests, a group of Grand Classroom students from Ohio. As we headed out to our tagging location we talked to the group about shark conservation and RJ Dunlap’s research. When we arrived at North Beach we set out our first ten lines and let them soak for an hour. While we waited, we explained how our guests would be participating in our research and what projects each measurement and sample were for.

After an hour we returned to check our lines. As the weight at the end of the first line landed on the deck I looked to the monofilament and saw it was pulled taut and pointing horizontally in the water, a shark for sure! The line was pulled in and soon we came face to face with a 215 cm (~7 ft) hammerhead! Due to our previous research we know that hammerheads are sensitive to capture stress so the RJD team quickly worked up the shark and released it.

RJD intern Jake helps Emily takes a blood sample from a shark’s caudal vein

We continued to pull lines, already pleased with the day’s turn out. Catching one shark is great and catching a hammerhead is always a wonderful find. Our luck continued as on the 11th line we pulled up a 199 cm (~6.5 ft) sandbar shark. Due to the heartier nature of sandbars, our guests assisted us in our data collection. As we worked up the shark we noticed that the shark already had a tag, and it wasn’t ours! This was the first time I had ever seen us catch one of our own previously tagged sharks, what a rare find! Our team was kept busy as in quick succession we caught two more hammerheads, the largest being a 318 cm (~10.4 ft) female. After that the activity on the lines began to calm down, and we ended the trip with one more hammerhead on line 25.

: A student performs a reflex test to check for stress by streaming water in its eye. By checking for the nictitating eyelid, the sharks ‘eyelid’ we can gauge the shark’s stress levels

In total we caught four hammerheads and one sandbar shark. I couldn’t help but feel lucky at getting to see so many hammerheads in one day. Before today I had seen few of them and to see so many was amazing. Thank you to Grand Classroom: Ohio and the rest of the RJD crew for an amazing day on the water.

A hammerhead shark swims off after workup