A major shark-research expedition aboard the internationally known M/V OCEARCH tagged four sharks in the Gulf of Mexico as of Nov. 6, says a participating Mote Marine Laboratory scientist who is collecting and studying shark blood samples in this team effort to gather previously unattainable data on these important top predators.
This multi-partner expedition — led by OCEARCH with scientific leaders from Texas A&M University — departed Nov. 4 from Corpus Christi, Texas.
So far, participants have deployed various scientific tags on four sharks: A 10-foot, 6-inch tiger shark was fitted with a satellite transmitter tag that tracks its location and provides real-time updates to scientists when the shark’s fin surfaces. A 6-foot, 9-inch bull shark was fitted with an external acoustic tag to help monitor its fine scale movements. And two scalloped hammerhead sharks, one 8 feet long and one 7 feet, 10 inches long, were fitted satellite transmitter tags to track their locations.
- Two of these sharks can be tracked by the public at: www.ocearch.org
Look for “Joseph” the tiger shark and “Buddy” the 7-foot, 10-inch hammerhead.
Mote Postdoctoral Research Fellow Dr. Heather Marshall collected blood samples from the tiger, bull and the 8-foot scalloped hammerhead for projects by multiple researchers on board, including her own research on stress in caught-and-released sharks. While it is often assumed that many sharks survive release, it is critical to understand how often they really do, and how survival rates vary with different circumstances and species. Such data are vital for management of sharks vulnerable to being overfished and/or becoming accidental bycatch.
- Read Marshall’s daily log below for a first-hand account of her research adventures aboard the M/V OCEARCH during Nov. 4-6.
Overall, the expedition goal is to tag, sample and release hammerhead, tiger and mako sharks. Participants hope to better understand: how the sharks travel in relation to Gulf habitats and structures, including natural and artificial reefs and oil/gas platforms; how shark habitats connect among the U.S., Mexico and Cuba — important information for international conservation efforts; and what physiology and health traits the sharks show, especially related to stress, body condition at release and capacity to reproduce.
- Read Mote’s initial press release with more details about the expedition. (Note that expedition dates changed after this release, due to weather delays.)
Mote scientist Dr. Heather Marshall’s daily log of shark research aboard M/V OCEARCH, November 2015
Wednesday, Nov. 4, 2015
We left the dock in Corpus Christi, Texas at 6 a.m., and traveled for six hours aboard the M/V OCEARCH to reach 35 miles offshore and 120-foot depths. The vessel Contender headed out before us to scout and fish. We arrived right before lunch, had lunch, and then Contender headed out for more fishing. Science team set up gear, reviewed the science plan as to who does what on the Contender and the cradle of the M/V OCEARCH, which lifts sharks out of the water temporarily for tagging and collecting samples. I then joined Adam on the stern of the M/V OCEARCH to help chum and fish for bait.
We then heard that the Contender had hooked the first shark of the trip: a bull shark! The science team loaded into the safeboat with their gear, and we went over to the Contender. We got sorted on the Contender before they brought the bull shark into the stern of the Contender. I got a blood sample first, then Jim Gelsleichter did an ultrasound (not pregnant), and we deployed an external acoustic tag for monitoring of fine-scale movements in the water. They put her back over the port side, “walked” her a bit – moved her in the water to help expedite her recovery – and then released her. We were excited to have our first shark of the trip! Soon after that, the sun set. We headed back to the boat and I processed the blood.
Thursday, Nov. 5, 2015
I woke up at 6:15 a.m., headed up to galley for breakfast, then made sure my gear was ready for a shark, which came quickly as Rob and I were chatting about white shark research in the tackle bar. The team had a 7-foot, 10-inch scalloped hammerhead hooked. It was too rough to get everyone into the safeboat, so Chris Fischer (aka “Fisch,” expedition lead for OCEARCH), Rob and Brandon just went to SPOT tag it and release it fast. The SPOT tag is a type of satellite tag that tracks the shark’s location and sends data back to scientists when the shark’s dorsal fin breaks the water’s surface. We watched as the boat moved past the M/V OCEARCH. They tagged it quickly and released it strong.
Soon after, they hooked a 10-foot, six-inch tiger shark! Matt and I went out with Rob and Fisch to join them. It was pretty wavy and we worked up the shark over the side of the boat. I sampled for blood right away and held the tail for Matt until my arms were giving out, and then swapped with Brandon. I drove while the SPOT tag was put on, and we released her strong, with low stress. We were pleased, even though it was a challenging tagging.
The team took a break afterward and ate breakfast. Later while chumming, we heard the team had a small blacktip shark hooked, but the wave conditions were worsening and Fisch made the call that it wasn’t worth the transport between boats for a blacktip, which made sense, considering the species we are tagging. Right away, though, they checked their buoys and had an 8-foot scalloped hammerhead! This time I, Matt and John (Dave Wells’ postdoc) went out, worked up the shark along the side of the Contender. I got a blood sample, and then they deployed a SPLASH tag instead of a SPOT tag, for Dave Wells. The SPLASH tag measures a shark’s location, like a SPOT, along with depth and temperature. We also deployed a PSAT, a satellite tag that will gather data on the shark’s position for a period of time – this one was programmed for 6 months – and will ultimately pop off, float to the surface and send its data to researchers. Then we let the shark go and it looked strong. We came back in the Contender, and even though there was still daylight, we finished tagging and sampling for that day, because the swell was getting too big. So I processed the blood, and Todd and Brett pulled the rest of the gear.
Friday, Nov. 6, 2015
I woke up around 6 a.m., grabbed coffee and joined everyone on deck. Todd was sorting out gear, then they left to fish. The Yellowfin showed up with Greg Stunz and an underwater videographer named Chris from Australia, and they helped with fishing.
We have a stow-away: a warbler (type of small bird) that found our boat out here and is staying fat and happy eating bugs on the boat. He’s been here two days. We all watch him and enjoy his hopping around the boat.
The Contender fished until dark, then it came in. The team is exhausted and caught no sharks. Luis made an amazing Mexican meal with chili rellenos, fish tacos, rice and many sauces. We’re looking forward to the rest of the trip and the chance to gather even more data on sharks of the Gulf.