Tag, you're it: ODNR tracks fish to learn about movement patterns, manage populations

When state fisheries biologists reeled in a haul of fish to study last December near Lorain, they found a 24-inch walleye with a tracking tag attached to its jaw. 

Using the information from the tag, they learned that this fish was first tagged 17 years earlier on the River Raisin, which empties into Lake Erie, in Southeast Michigan. 

The fish, a male, was 17.1 inches long when it was fitted with the jaw tag in 2006.

That walleye is one of thousands of fish fitted with some sort of tracking device on the Great Lakes through various projects by different agencies to help monitor fishes’ movements, life span and mortality. 

Since 2010, some of these devices are tags that have been surgically implanted into the fish and emit an acoustic signal that pings on receivers located throughout the bottom of the lakes and some of their tributaries, giving a record of their movements within the lake and between bodies of water. 

This network of receivers is part of the Great Lakes Acoustic Telemetry Observation System, and agencies across the Great Lakes have used them as part of different fisheries research projects. Think of it like cars on the Ohio Turnpike with EZ passes going through a toll booth while their passes are scanned and movements and payments logged.

“We joke that if you’re a walleye or tagged fish, you can swim, but you can’t really hide,” says Matthew Faust, Fisheries Biologist II for the Ohio Department of Natural Resources, Division of Wildlife, Sandusky Fisheries Research Station. 

To implant the tags, biologists net the fish, anesthetize them, and complete the surgical procedure to insert the device into the body cavity in 4-5 minutes. (Andrew Muir/Great Lakes Fishery Commission)The improved technology allows biologists to track the fish and see whether they stay close to where they were tagged, whether they move into the different basins of Lake Erie or its tributaries or whether they travel up the Detroit River ultimately into Lake Huron. 

“An Ohio Fish isn’t necessarily an Ohio fish year-round,” Faust says.

Jaw tags and similar tags did not have the acoustic tracking ability and provided data only through the fish being caught and reported. The implanted acoustic tags give researchers much more information. 

The data helps biologists obtain a better view of the different populations of fish in Lake Erie, such as walleye and perch in different basins of the lake and provide information that can help them manage fish populations. 

In 2023, there were 583 receivers in Lake Erie, and 101 receivers in the Detroit River and other Lake Erie tributaries, Faust says. There were 647 on Lake Ontario and 640 on Lake Huron. 

Had the walleye ODNR caught last December with the jaw tag had an acoustic tracker, biologists would have known about its travel habits throughout Lake Erie and whether it moved to any other bodies of water.

The Lake Erie Committee, which includes stakeholders from different jurisdictions around Lake Erie, determines how many walleye and yellow perch can be harvested from the lake each year through commercial fishing and sport fishing while maintaining a healthy population, says Travis Hartman, ODNR Lake Erie Fisheries Program Administrator. 

Although the information from the acoustic telemetry tagging of fish is not directly used for those decisions, Hartman believes that in the future, it will help the committee calculate the true natural mortality rate of each fish population and better understand the rate the reproducing fish are being taken from the lake.

“The benefits of the acoustic tagging increase as additional projects and years of data are continually collected, and we are now in a position where we can start to leverage numerous projects to address important questions,” he says. 

“It’s going to be huge to have this data source,” he adds.

How it works

Through the acoustic telemetry tagging, ODNR focuses mainly on walleye – the most tagged sport fish - smallmouth bass and yellow perch, but it also works with other agencies that have tagged and are studying other types of fish, Faust says. 

When the fish are released, the tags start pinging on the receivers placed throughout the system.  (Andrew Muir/Great Lakes Fishery Commission)Those projects include Toledo Zoo and University of Toledo releasing sturgeon as part of a project to rehabilitate the endangered fish’s population on Lake Erie, several agencies studying the invasive grass carp’s population and an international collaboration to study lake whitefish in the lake’s Western Basin. 

ODNR used jaw tags through the late 2000s. Then it moved to implanting the acoustic tags in the fish. Tags put in walleye and sturgeon can last up to a decade.
If an angler catches a tagged fish, they can report the tag to ODNR and receive a $100 reward. This allows the agency to track how many fish were harvested through sport-fishing.

To implant the tags, biologists net the fish, anesthetize them, and complete the surgical procedure to insert the device into the body cavity in 4-5 minutes. They pour fresh water over the animals’ gills throughout the procedure.

“We try to minimize the handling and containment time,” Faust says. 

Then the fish are released, and the tags start pinging on the receivers placed throughout the system. 

“On a calm day in the Western or Central Basin, receivers can ‘hear’ the tags well over a kilometer away, sometimes as far as 3-5 kilometers away with the more powerful tags,” Faust says.

Last year, ODNR tagged 150 walleye during the spring spawning season near the reefs and Bass Islands of the Western Basin and 50 in the Central Basin in and around the Grand River near Fairport Harbor. 

The agency also tagged 126 smallmouth bass around the Bass Islands and in the Grand River and Conneaut Creek that feed the Central Basin. 

Some of the findings

Watching the movement of walleye, which prefer colder water, has helped provide biologists with a view of how different populations of the tagged fish in the lake behave. 

Walleye in the Western Basin – from Toledo to Sandusky – tend to move to the cooler waters of the deeper Central Basin – the area from Sandusky to Erie, Pennsylvania - in the warmer months. Then in the fall, they slowly move back to the Western Basin. They tend to winter in one place and go back to where they were tagged in the spring.

A small number of Western Basin walleye travel much farther. A Sandusky Bay walleye was tracked going over Niagara Falls. 

Fewer than 1 percent of the tagged walleye travel up to Lake Huron, perhaps because there is a good forage food source there and fewer walleye around to compete with, Faust says. 

“We have seen a few more walleye move north into Lake Huron in recent years, possibly as a response to the increasing number of walleye in Lake Erie, but we do not know this for certain,” Faust says.

Biologists believe the population of walleye in the Eastern Basin – from Erie, Pennsylvania, to Buffalo, New York – is smaller than those in the Western and Central basins, but they don’t know exactly how much smaller. 

“Eastern basin walleye do not move very far outside of their home basin, but we do not know exactly why this is the case,” Faust says. “It could be because there is plenty of cool water and forage.”

What’s next

This year, ODNR plans to tag 200 more walleye and 150 smallmouth bass between the reefs of the Western Basin and Sandusky River, Faust says.

They’re also planning to tag 150 yellow perch in the Central Basin to expand their work with the tagging and monitoring of this species. Tagging of yellow perch is relatively newer than implanting the devices in larger fish, Faust says. 

Perch require smaller devices, which also means they have a lower range of acoustic detection. For example, if walleye can be heard from a kilometer away on a good day, a yellow perch might only be heard from a quarter to half a kilometer on a good day, he says. 

There are also some concerns about the barotrauma that causes damage to the fish and is caused by pulling them from greater depths. For the past two years, the Division of Wildlife and U.S. Geological Survey have been working on the best way to safely pull and tag the fish.  

“Basically, we want to know what combination of capture method, tag size, and season gives us the highest survival rate to maximize our chances of success before we try to release hundreds of yellow perch across Lake Erie,” Faust says.