Tag, You’re It
An early morning start awaits Florida Tech researchers in shark biologist Toby Daly-Engel’s Shark Conservation Lab: field work beckons. Many hours will be spent on a boat fishing for sharks and collecting valuable data for various research purposes.
The field work provides an opportunity to collect samples and other data that will be used in the lab and shared with other collaborators. Tissue samples can be used for conservation genetics and molecular ecology efforts and tagged sharks can have their movement monitored. This field work experience also provides new researchers with invaluable real-world experience.
“When we go fishing, it’s kind of like you take samples for everybody,” Daly-Engel said. “The people who are studying DNA, the people who are studying stomach content, whatever else, because we don’t want to disturb the animals too much. We maximize our use as collaborators because those samples are going to be coming to us anyway, so it’s a great opportunity for the students to learn how to do that part.”
There are different types of tags, such as simple spaghetti tags or M tags. These small plastic pieces are inserted into the animal and can provide information to people who may recapture the animal to allow them to contact the scientists and provide location data to determine movement and size of the animal to determine growth rates. There are also high-tech tags that deal with satellites and receivers that capture location data and movement of sharks.
There is no shortage of ways to use tag-derived data.
For example, a collaboration between Florida Tech and the New England Aquarium used tagging to study the stress responses of blacknose sharks during recreational fishing. Researchers fished for the sharks with a rod and reel and tagged the shark with an accelerometer tag, which records the movement of the shark. When the tag fell off the shark after a few days, the team retrieved it.
Findings showed that blacknose sharks did well after capturing and handling in the recreational fishery and indicated they weren’t all that stressed from these interactions. The field study also provided opportunities to collect tissue samples on other shark species.
“We benefited from that project as well, because even though we were targeting blacknose sharks, which are small, common coastal species, we actually are able to catch a lot of different sharks,” Eloise Cave, an integrative biology doctoral candidate in the Shark Conservation Lab, said. “That allows us to build up our tissue bank of specimens. Not only are we getting to go shark fishing for this specific project and tagging these sharks for this specific project, but we take advantage of collecting tissue samples of all different species.”
Shark fishing efforts and the tissue samples collected have benefited many projects in the Shark Conservation Lab, including the work of Lily Borema, an undergraduate biology major who is researching multiple paternity of sandbar sharks. She focuses on immune genes to determine the number of fathers in a shark litter and how those immune genes are inherited from their parents.
“We’re doing gel electrophoresis, we’re sequencing genes and alleles,” she said. “I realized very soon that it’s less of, ‘I’m going to be working hands on with sharks,’ and more of, ‘I’m working in a genetics lab and I’m sequencing genes and I’m making a family tree based on the genes of these sharks that I have a tiny little DNA sample from’. It was very interesting and a great learning experience.”
Going out into the sea can be exciting for researchers, but, like any type of fishing, it’s an exercise in patience, as well. While it can mean spending hours or even weeks in the hot Florida sun without catching any sharks, the entire process is an opportunity for students to learn.
“We are teaching the students how, not just how to set a line and how to drive a boat, but also how to handle the animals so that both the animal and the handler are safe and emerge unscathed from the experience,” Daly-Engel said.
