Shark Tagging with Westminister Christian School 9/19/2014

By Hanover Matz, RJD Intern

September 19th proved to be an exciting trip to begin the fall RJ Dunlap shark tagging season. Students from Westminister Christian School joined the RJ Dunlap interns along with Dr. Neil Hammerschlag at the Crandon Marina for a successful day of shark research. The interns loaded the gear onboard as Captain Eric prepared the Diver’s Paradise boat for departure. Once the students arrived, we were ready to set off for the nearby waters just off the coast of Miami. As we made our way out to sea, Dr. Hammerschlag briefed the students on the various research techniques we would be employing that day. Morphological measurements, fin clip samples, nictitating membrane tests, and blood samples would be collected in order to gain valuable data from any sharks we caught.

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Dr. Hammerschlag briefs the students on research procedures

After reaching our destination, the RJD interns with help from the students of Westminister Christian began setting out the drumlines. Each line consists of 70 feet of monofilament attached by a swivel to a weight that rests on the sea floor. The swivel allows any hooked sharks to remain swimming and breathing, as sharks are ram ventilators. At the end of the line is a circle hook that allows for the safe capture of sharks without damaging their internal organs. Once ten drumlines had been set in the water, they were allowed to soak for an hour. The students helped the RJD interns collect environmental data in the meantime on water temperature, salinity, and dissolved oxygen levels. This information provides a better understanding of the environmental conditions encountered by different shark species.

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An RJD intern helps a student collect salinity data

Once one hour had passed, we returned to the lines to see what we had caught. Our first shark of the day was a small blacknose shark. The RJD team quickly brought the shark onboard and secured it to the platform. A water pump is placed in the shark’s mouth to pump water over its gills, helping it to breathe and remain calm during the workup procedure. The students assisted in quickly measuring, sampling, and dart tagging the shark before it was released back into the water. While the blacknose was a good start to the trip, the weather decided to take a different course. A steady rain began to pelt the boat as we headed to collect the other lines, and we could see downtown Miami receiving its own dose of showers in the distance.

The weather may not have held up, but our luck in bringing in sharks did. The team was able to bring in a large nurse shark next. Unlike the blacknose shark and other shark species, these powerful animals lead a less active lifestyle on the ocean bottom, and do not need to continuously swim to breathe. We performed a work up on the nurse shark, collecting all the necessary data, and then released it back into the water. Samples such as dorsal fin clips and blood can give us a better understanding of shark diets and physiology.

The remainder of the trip saw us bring in another nurse shark and two tiger sharks. The tiger sharks were truly an amazing sight for the RJD team and students. Both tiger sharks measured over six feet in length. Such large animals are key predators in the ocean ecosystem, often exerting top down control from the peak of marine food webs. One of the tiger sharks seen that day circled the boat a few times, offering us a beautiful sight of its dark stripes that give the animal its common name. With three more sharks tagged and released, we reached a total of five sharks for the day. In an area so close to a major city with increased pressures on marine ecosystems, even seeing one shark can be a lucky experience. The data the Westminister Christian students helped collect on these sharks will be invaluable in contributing to ongoing research in shark biology and conservation.

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A tiger shark is successfully released by the RJD team

We headed back to the dock after an exciting day of shark research. The students departed from the boat, hopefully with a greater appreciation for one of nature’s most amazing predators. We cleaned and stored the gear, enthusiastic after what promised to be a great start to a successful season of shark tagging.


Shark Tagging with South Broward 9/26/2014

By Jake Jerome, RJD Graduate Student and Intern

Last Friday marked the first time that RJD went shark tagging out of West Palm Beach, and it proved to be an exciting first! We were joined with one of our more frequent school groups, the South Broward Reef Dogs. After making the trek up to West Palm, we loaded up the Deep Obsession with our gear and set out with the crew from Jim Abernathy’s Scuba Adventures aboard.

With choppy seas and rain falling down on us, we launched our first 10 drumlines in the hopes of catching our first shark in West Palm Beach. Despite the weather conditions, everyone on the boat kept spirits high and we all had a good feeling about the day. After letting the lines soak and collecting some environmental conditions with the help of our guests, we began pulling up our lines.

After a slow start and the rain still pelting down on us, we managed to pull up an Atlantic Sharpnose, the most abundant shark species in South Florida. Once we brought the shark aboard, we began our quick workup to collect data for our over 9 research projects. In less than 4 minutes we were able to collect multiple morphological measurements, a fin clip, draw blood, place an identification tag and perform nictitating membrane stress tests. Once these procedures were completed, we released the shark and returned to pulling in our lines.


A participant helps take a fin clip, a small cartilage sample that will help reveal long-term toxicology and dietary patterns.

After our first shark we seemed to hit a slump going into our second set of drumlines. After switching the crew around, our luck took a drastic turn for the better! While pulling up one of our final drums of the second set, we knew immediately we had something big on the line!

After hearing our captain shout “Shark,” all eyes turned desperately towards the water looking for the animal. Once the shark hit the surface we could see that it was a hammerhead! After we had the large male secured next to the boat, we realized that we had a Scalloped Hammerhead, a species that we rarely get to collect data from. Knowing this, we quickly collected as much data on the animal as possible and then attached a satellite tag so we could follow the shark’s movements after we released him. For the rest of trip, spirits remained high and we were fortunate enough to catch two more sharks, a feisty blacktip and a large bull on our very last line of the day.


Measurements of the scalloped hammerhead are quickly taken while a satellite tag is being attached.

All in all, our first trip out of West Palm Beach proved to be a successful and exciting one. We were able to collect data from four sharks of four different species and were able to satellite tag a Scalloped Hammerhead! Thank you so much to the always awesome South Broward Reef Dogs and the rest of the crew from the day.


Our awesome group for the day, the South Broward Reef Dogs!

Breaking in the new boat!


Last weekend, students from the Archimedean Academy joined the RJ Dunlap team for the first of many voyages on Captain Curt’s new boat! This new vessel, named after Captain Curt’s soon-to-be-born daughter, is a welcome addition to RJD. It’s size, range, and cabin space will allow our team to do even more research in the Bahamas and other far-away sites.

Students from the Archimedean Academy pose on Captain Curt’s new boat!


We went to Middle Grounds, a site in the Everglades National Park known for having lots of sharks. Nutrient-rich runoff from the Everglades creates a rich feeding ground for many species of sharks. Some of our highest catch-per-unit-effort (a measure of shark abundance) has been at this site. Our catch didn’t disappoint- in total, we caught, tagged, and released two blacktip sharks, an Atlantic Sharpnose shark, and a blacknose shark.

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