Detecting Whales by Acoustic Signature: New Tech Deployed for Underwater Monitoring

Workers deploy a whale monitoring buoy in state waters.
Workers deploy a whale monitoring buoy in state waters.
LEAH CROWE/Courtesy of the Division of Marine Fisheries
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Workers deploy a whale monitoring buoy in state waters.
Workers deploy a whale monitoring buoy in state waters.
LEAH CROWE/Courtesy of the Division of Marine Fisheries
Detecting Whales by Acoustic Signature: New Tech Deployed for Underwater Monitoring
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The state Division of Marine Fisheries (DMF) and the Woods Hole Oceanographic Institution (WHOI) have teamed up to improve North Atlantic right whale monitoring in Massachusetts.

CAI’s Gilda Geist spoke with Erin Burke, Protected Species Program Manager at the DMF, to learn more about the state’s new approach to tracking right whales.

This is one of the buoys the state uses to monitor the presence of North Atlantic right whales.
This is one of the buoys the state uses to monitor the presence of North Atlantic right whales.
LEAH CROWE/Courtesy of the Division of Marine Fisheries

Gilda Geist: The Division of Marine Fisheries and the Woods Hole Oceanographic Institution have launched an innovative passive acoustic monitoring network. So, can you tell us a little bit about what that means?

Erin Burke: Well, first, I also just want to clarify that this is sort of innovative from a DMF standpoint. We’ve never done acoustic monitoring before, but this technology was developed by WHOI, and they have used it in other places for a number of years. So one of the main things we do at the Division of Marine Fisheries is monitor right whales in our coastal waters. And we have mainly done that through aerial surveillance, but you can only do that at certain times of the year and in certain places. So we don’t get full coverage of state waters looking for the presence of right whales. So we’ve expanded our monitoring program to include acoustic surveillance, and we’re doing that through two methods. One is the near real-time buoys—one is in Cape Cod Bay and one is off Gloucester. And then to get coverage across the rest of state waters and in adjacent areas, we’re deploying 17 bottom-mounted archival acoustic recording devices. The real-time buoys are a collaboration with Woods Hole. This is their technology. Their analysts are checking the real-time detections, and they have partnerships with other entities up and down the East Coast, too. There are other real-time buoys, not just the ones in Massachusetts. They have a number of them around.

GG: This is an acoustic monitoring network, so what kind of sounds is it listening for? Is it quite literally listening for the sounds that these whales make?

EB: It’s capturing all sounds, and then the way that they pull out the whale vocalizations is through software. So they do that on the real-time buoys, and then we will use that same software when we analyze the recordings from our bottom-mounted archival units as well. The software classifies and detects the whale localizations based on their acoustic signature. Basically, the calls of a right whale that we’re looking for are an “upcall” and have a certain acoustic signature. You can kind of pull that out based on what the sound kind of looks like.

This graphic shows how the acoustic monitoring buoys work.
This graphic shows how the acoustic monitoring buoys work.
Courtesy of the Division of Marine Fisheries

GG: You and your team were out on Buzzards Bay recently, deploying the 17th buoy for this project. Can you tell me about that? What was that like?

EB: It’s been great. I mean, this is kind of the easy part. You know, we’re putting out these monitors, and it’s a bottom-mounted mooring that rises, like, seven-to-ten feet off the seafloor that has a hydrophone and acoustic release. And this is the first time they’re going in the water. What’s really going to be interesting is when we go out and trigger them to the surface, and hopefully they show up and they haven’t been moved by mobile gear or been sort of sanded in. And then we will download the data, swap out the data, clean up the units—they’ve been in the water for five months—and then re-deploy them. That’s going to be the really “nervous parent” part—when we go out there and trigger them to the surface and wait for them to come up and hope they show up.

GG: What is this data going to be used for? How will it help right whales?

EB: You know, part of the way that we craft regulations that are as effective as possible and not unnecessarily burdensome on the industry is having a good sense of where and when right whales are. And so this will give us a better understanding of the seasonal and temporal presence of right whales based on these acoustic detections. And then we can use that to refine current regulations or craft new ones. You know, an improved understanding of the presence of right whales in state waters and adjacent areas will help us craft more effective conservation measures for right whales, and possibly tweak stuff that we have on the books if it’s not necessary. We want to be surgical because there are impacts to the industry from fish enclosures or speed restrictions.

GG:So there’s this website, Robots4Whales, where it looks like folks can go see this data for themselves.

EB: Yeah, it’s really interesting. So you can click on, not only our buoys, but others as well, and dig into the detections—not just right whales, but fin whales and humpback whales. You can take a look at how they analyze the calls and made the decision that yes, this is a confirmed detection.

This story was originally published by CAI. It was shared as part of the New England News Collaborative.

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