Last month, members of the R.J. Dunlap Marine Conservation team joined Jim Abernethy aboard the Shearwater for a week of shark research and diving. The RJD research team included myself, Dr. Hammerschlag, Captain Curt Slonim, and Fiona Graham. Visiting researcher Dr. Duncan Irschick from UMass Amherst, and Marco Flagg of Desert Star Systems also joined us for a chance to see how RJD performs our research and to interact with some awe-inspiring animals, as did a group of citizen scientists. The goal of this expedition was to gather biological samples and apply satellite tags to as many Tiger Sharks as possible, while still making sure the research was carried out in a way that did not stress the sharks.
Along with the blood, muscle, and fin samples that we usually take on our research subjects, we also took a series of morphometric measurements for Dr. Irschick’s research. He will be using these measurements to look at, among many things, how the shark’s related to the way they move. We also used an ultrasound machine on each female Tiger shark to determine if the sharks in the area are pregnant. On the first day of research, the team satellite tagged the largest Tiger Shark of the trip, a 305 cm (9.5 foot) female. We were also able to place dart tags and collect data on a few lemon and Caribbean reef sharks as well. On the second day of research, we satellite tagged and sampled four tiger sharks including one small male. This was surprising, as most of the Tiger sharks seen at Tiger Beach are females. On our third and last day of research, we satellite tagged one more female Tiger shark.
After 3 days of research, it was time to go scuba diving with these beautiful animals. Jim Abernethy and his crew have been diving in the waters of Tiger Beach for years and no operation knows the sharks that frequent the area better. After a safety briefing on the proper way to dive with sharks, we made our way into the water and onto a beautiful reef. There were Caribbean reef sharks swimming all around us, but the real star of the dive was a charismatic goliath grouper named Max. Max is known to frequent this reef and is very friendly – he even let me scratch under his chin! On my second dive on the reef, I got a quick glimpse of a large Tiger shark as soon as I got in the water, but it (probably a she) left and the rest of the dive was filled with more Caribbean Reefs and some time with Max.
On the last day of the trip, the group was treated with a visit from Emma. Emma is a 14-ft Tiger shark who frequents the area. Jim Abernethy has interacted with her on countless dives over the past 8 years. While Emma has safely interacted with SCUBA divers many times, it is important to remember that she is still an apex predator who is curious of what these strange divers are doing around her. I had a close encounter with Emma myself as she became very curious of both my camera and me. It was truly an amazing experience to get so close to so many beautiful sharks of so many different species. Not only was the experience amazing, but the team also collected valuable data on some of the most important predators in Bahamian waters. The satellite tags are transmitting and everyone will be able to see where these sharks are going.
If you would like to join Dr. Hammerschlag on a future Bahamas expedition, please contact him. The next trip to Tiger Beach is 10/17/13-10/23/13. The RJ Dunlap Team would love to have you on a future research expedition!
Kyra Hartog
R.J. Dunlap Intern
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