Sharks are sticking around in Long Island waters later in the season than usual. That’s according to a new study from Stony Brook University's School of Marine and Atmospheric Sciences. It found migratory east coast sharks leave their summer homes in the Northeast up to a month later than normal.
WSHU's Sabrina Garone spoke with Jon Dodd. He is the executive director of the Atlantic Shark Institute based in Rhode Island, which had a hand in the research.
WSHU: Tell me about this data that was collected.
JD: It was a five-year study between 2018 and 2022, so this isn't a month or two of data! This is hundreds of acoustic receivers, well over 100 sharks, and years of data. So I think it's a real tribute to collaboration because you can't do this alone. I think Maria did a great job of pulling all these resources together to write an excellent paper that I think has a lot of value and a lot of people talking.
WSHU: What are the implications of sharks migrating later in the season? Could you explain the major findings there?
JD: We've got at least, in this case, six species of shark with an average delay of about 12 days in terms of their southern migration. So yeah, this has implications on you predatory relationships, this has implications on things that are coming into the area sooner than they have in years past because of rising water temperatures, and we're also seeing species that were here in big numbers that we now find more so in Massachusetts, Maine, in Canada — so this is the thing you seen over the last 10, 20, 30 years. It doesn't seem to be slowing down.
WSHU: You mentioned the rising water temperatures, but are there any other factors you think could've contributed to this, or is that pretty much the main reason?
JD: Rising water temperatures are kind of the big play with most of these sharks. Most of these sharks are cold-blooded, so they need to surround themselves with water temperatures that they can really function in. Just a handful of sharks that are warm-blooded — they can increase their body temperature. So most of them need to go where biologically they're optimized. There needs to be a food source, of course, but most of them want to be in a temperature that allows them to optimize what they do and how they do it. So if if they find the water temperatures are conducive to sticking around another week, or two weeks, or 30 days, then they'll do it, and in this case just about every one of them did.
WSHU: I think the last time we spoke, we were talking a lot about, especially in Long Island waters, restrictions on menhaden fishing being put in place, and that was the reason why sharks were being spotted more. Is this something you're still finding, specifically in and around Long Island?
JD: There are still some really large schools in Menhaden. We were just two days ago along the south shore of Long Island — a big resource for a lot of game fishing, striped bass, and bluefish. But also sharks, so it's a really significant food source, and if you've got basically good temperature and you've got a good food source, that's pretty much what sharks are looking for. You can have great temperature but no food, and they can't stick around. You can have wonderful food sources, but if the water is simply too cold or too warm for them, they need to move further north or south. But when you've both of those, that's a recipe for some shark activity and presence. I think that's also what we saw here in the study.
WSHU: Are there any specific species that you're worried about with sharks sticking around longer, and where could their populations be impacted here?
JD: Well, you know, just in the last year we picked up a neonate — a very young spinner shark. Really odd for that to be up here with an umbilical scar on it. We're also running into a number of small white sharks, so what we're always concerned about is these nursery areas where sharks go to grow up. They grow to a status or a size where they could be a little more protective and assert themselves a little bit more. So when you start seeing water temperature changes and sharks coming into areas that ordinarily aren't, I always get concerned about some of these sharks that are trying to grow up, and trying to get to adulthood so they can reproduce. That always concerns me because these areas have been around for a while. The sharks love the fact that they can go there and be protected, and if you suddenly start introducing predators that they're not familiar with, they could become a food source, and then we've got another domino.
WSHU: Why should regular people care about sharks?
JD: Yeah, that's a great question. Shark health is ocean health, and ocean health is our health. The oceans simply cannot be healthy without healthy numbers of sharks. They just make sure they keep everything else in check, most of them. A lot of them are apex predators, and they have the tier two level — you know, a lot of these larger game fish. So you can imagine the domino effect when you remove the apex predator, and then those tier two fish suddenly grow to a size and a mass that they devour everything underneath them.
The oceans are the lungs of the planet. We better take care of the ocean for a whole bunch of reasons, and sharks are critical to ocean health. So our hope is that people can connect the dots on that, and care a little bit more about sharks that maybe some of them do. I think it's just something that fascinates people — sometimes scares them a little bit, but hopefully fewer people as they get a sense of the value of these sharks and the importance of ocean health, they take a different view of them! Even though they could be a little scary at times and you wanna get out of the water, at the end of the day, they don't make a lot of mistakes. You know, if sharks really thought we were food — forget it! You couldn't go in the water. Every now and again, one of these sharks makes a mistake, and it makes worldwide news. But it's remarkable and surprising for people to see how close they come to sharks many, many times over their lifetime and they never knew it!
