Where are white sharks swimming off Maine? A conversation with the state's new expert
There's been more reporting this summer about sharks. There have been some incidents of people bitten by sharks, and in response, more concerted efforts to watch for them.
The state of Maine this year created a new position to better monitor sharks, which has now been filled by Matt Davis.
Morning Edition host Irwin Gratz spoke with Davis about sharks in Maine. Here's an edited version of their conversation.
Gratz: Over a long stretch of time, we have seen an increase in white shark populations, correct?
Davis: That is correct. So white sharks were a common bycatch species and many fisheries prior to the 1990s. In the 1990s, there were some protections put in place federally that made it illegal to target or fish for white sharks in U.S. waters. And with those protections, their populations have been able to slowly begin recovery over the last several decades.
Well, what kind of tools are at your disposal to track white sharks off the Maine coast?
Here in Maine, the primary tool that we use is called acoustic telemetry. So the general way this works is you have someone attach one of these tags to a shark. And that is usually attached at the base of the dorsal fin, which is that large fin that you see on the back of sharks. Any time one of these animals carrying a transmitter comes within a couple hundred meters of one of your acoustic receivers, it sends what we call a detection, or you can think of it sort of like a radio ping, that sends a timestamp to that receiver to say, Tag 12345 was here on this date at this time. At the end of the year, we can bring those receivers back to shore and download the data to see what tagged animals have swam nearby. Now there does exist real time acoustic technology. So we have two here in Maine. One is based in Saco Bay, and the other one is currently at Popham Beach. And these actually use cell towers to transmit detections in real time to beach officials to alert beachgoers if a detection has been, well, detected.
Can you give us some idea of what you're finding?
This year is the first year we've used the live receiver technology, otherwise known as real time technology, and those have not yet detected any sharks in real time. As far as the what we call passive acoustic receivers, we have picked up a total of 39 individual white sharks in the one and a half years of data that we have currently.
Of the 39 detections you've seen over the last year and a half, are they beginning to paint a picture of where the sharks go, where we see more of them, fewer of them, etc.?
It's really hard to say. When you only have a sample size of one and a half years, it's hard to say what is something we could consider normal behavior or what could be an anomaly or, you know, out of the average. Now that said, some of our preliminary data does suggest a couple spots to be particularly high in the number of sharks detected. That would be near Hermit Island, which is just west of Popham Beach, which last year alone detected 18 different individual white sharks. And then also one of our collaborators had a receiver near Seguin Island which detected more than 20 individual white sharks. The best estimates we have are that these habitats do provide significant or important access to prey sources such as seal populations, for instance.
What would you say to people about the things they can and should do to make sure they're safe when they're in the water?
So there are quite a few things that you can do and ways that you can more or less lessen your chances of interacting with a white shark. So some of these tips would be to swim with a buddy; sharks typically like to isolate their prey. So if you're with a buddy that lessens your chance. Avoid excessive splashing at the surface because that can mimic the vibrations in the water of an injured animal. Avoid schools of fish or seals. These are common prey items of white sharks and you don't want them to accidentally mistake you for food. Avoid wearing shiny jewelry because that can sometimes appear like the scales of the fish. And you want to avoid swimming at dawn and dusk.