A hammerhead shark was tagged for the first time in history in Rhode Island this week. Jon Dodd is the executive director of the Atlantic Shark Institute in Rhode Island. He joined GBH’s Morning Edition to talk about the tagging, and how warming waters are impacting shark migration patterns. What follows is a lightly edited transcript.
Tori Bedford: Jon, how did [the tagging] happen?
Jon Dodd: It’s kind of funny. We were actually out doing some sandbar research. It’s another shark that we’re doing a project on here in Rhode Island, and we ran into a couple of them and tagged them, so that was successful. We had a drone with us and we said, ‘Hey, let’s take a flight over to a spot that I think we might see some hammerheads on. We’ve got some reports.’
[Videographer] Tomas Koeck was at the helm and said, ‘We got a shark, hold on a minute.’ And then he zoomed in and said it’s a hammerhead. Now, what a lot of people know, some people don’t know, is that there are different types of hammerhead sharks. So you got great hammerheads, you got scalloped hammerheads, you got smooth hammerheads. So a hammerhead is kind of this generic term for a shark with that hammer cephalofoil. So we were able to zoom in deeper and closer and closer and closer, and where we were able to realize that we had a scalloped hammerhead, which are listed as endangered, critically endangered. So we were pretty psyched to see that it was one of those.
Bedford: Do we not see a lot of scalloped hammerhead sharks around this region because they don’t come up all this way or they’re not native to here, or is it because of how endangered they are? Like, should we be happy about this, or is this an indication that the ocean’s warming and everything’s bad?
Dodd: Yeah, that’s a really good question. And unfortunately, we’re going to talk about warming ocean temperatures. So these sharks like it in the 70s and 80s Fahrenheit in terms of water temperature. Unfortunately, we have water temperatures that are rising. We’re seeing our cold water sharks like our blue sharks, they’re really enjoying Maine and Canada now. So we’re seeing a shift — we’ve got these hammerheads coming in, we’re seeing some spinner sharks and blacktips, again southern species.
These sharks are cold-blooded, so they need to surround themselves in water that they really like, and as a result, to have them here is really interesting. It’s a good opportunity for research, but it’s also telling us that our waters are warming to the point where they find it comfortable to be here.
Bedford: What kind of tag did you use for this shark?
Dodd: This tag is a 10-year acoustic tag. It has a little pinger on it, and you can imagine it’s like a Social Security number. It’s about the size of four inches, maybe a cigar circumference, and it puts out a ping once a minute, believe it or not, for 10 years. And if it passes an acoustic receiver, of which there are thousands up and down the East Coast, that receiver will register that shark’s ping.
So it says shark number 865422 was pinged off of New Jersey, pinged off of New Jersey, different locations as it goes North and South. And then we upload that data — all of the researchers do — to a shared database. And allows us then to build literally a map of where that shark goes up and down the East Coast for a decade.
Bedford: Not to be human-centric about this, but before we wrap up, I do want to ask you, if more sharks are coming into the water, if the waters are warming and we’re getting different kinds of sharks, should people be more concerned about going to the beach or being more on top of theSharktivity app?
Dodd: Yeah, that’s a good question and a fair question. So first, we’re in a situation where we’ve got this shifting understanding of shark presence, right? Because we decimated them in the '70s, '80s and '90s. So when we see more and we’re like, 'wow, it’s more than there’s ever been.’ It’s really not.
That being said though, when you think about a sand tiger shark, you think about a spinner shark, you think about a blacktip shark — those are coastal sharks and they’re small. They do nip. There’s never been a fatality associated with any of those sharks, including hammerhead, by the way. So we just tell people to stay away from swimming at dawn and dusk, swim with friends, don’t go out over your head, be observant. If you see a bunch of baitfish in the water, be observant, if you see seals in the water.
But the odds are far, far greater, unfortunately, that you will drown at the beach — much greater than you’re going to encounter a shark. So we like to tell people, be more concerned about undertows and rip currents and things like that. And if you see something that you’re not sure about, just get out of the water and take a break.
