Acoustic Monitoring

What's one key way that researchers can monitor what's living in Channel Islands National Marine Sanctuary? Acoustic monitoring! With acoustic receivers, we can get the exact position of tagged animals like leopard sharks, sicklefin lemon sharks, juvenile white sharks, and sevengill sharks, which use the sanctuary as habitat and help maintain the ecosystem.


NOAA's Office of National Marine Sanctuaries works to protect several marine species, many of which are vulnerable or endangered. So, how do we do that?

We're looking at the connectivity and the movement of animals in and around the Channel Islands, off the West Coast of Southern California.

So we put up this equipment to listen for a variety of animals that may be around the sanctuary—we're partnered with a couple different researchers—and we put out this array around the islands to kind of watch where fish and different species that we're interested in move in between or around the islands.

In order to figure out what organisms are in the sanctuary and where they are travelling, we use VR2 acoustic receivers. Our research team has used acoustic measurements in the Channel Islands since 2010. My understanding is they can detect the acoustic tag in a fish from a distance of maybe, what, a quarter mile or so. Maybe a half mile. Depends on the sea conditions and the temperature and things.

So I'm surprised at how many tags it actually detects, because the fish have to swim within the range of the receiver. This method works well because we can get the exact position of the animals, and the tags last several years. Satellite tags have shorter lifespans and less exact positions.

Here in the islands, we've detected leopard sharks that come as far as La Hoya. We get white sharks that have been tagged off LA and Malibu. We've even gotten sevengills that come all the way from San Francisco.

So, there's a wide variety of animals that come down and use the Channel Islands as habitat. So, why is all of this important? One of the animals we tag, the Juvenile White Shark, is at risk of endangerment.

White Sharks are top predators in their ecosystems, essential to maintaining stable populations and keeping diseases from spreading. If these sharks go extinct, the ecosystems we depend on in California for food and recreation are more likely to deteriorate.

By understanding their habitat, we can better aid in the preservation of these sharks and other species.