Acoustic tracking technology has been used for some time to study the migration and movement patterns of fish. In Lake Erie, this is no different, as crews from the Ohio Department of Natural Resources (ODNR) have been relying on acoustic tags for years to study sportfish in the most shallow of the Great Lakes.
The lake is famous for its walleye, so perhaps it’s not surprising that scientists are studying the movement patterns of these fish. In one project using acoustic telemetry, scientists from ODNR are joining with others, including some student researchers from Ohio State University’s Stone Lab, in tracking the movements of walleye around Lake Erie.
This effort is relying on implanting acoustic trackers into walleye spawning below a dam located in Ballville Township, just outside of Fremont, Ohio. The trackers in the fish, along with receivers placed throughout Lake Erie and neighboring lakes and streams, act much like systems in place on many U.S. turnpikes to monitor the movements of cars through toll booths, scientists say.
This is because when a fish swims by the receivers, the system basically does the same thing that the toll booth system does with cars, but it instead logs the movement of a living creature — when a fish swims by a receiver, that gets recorded.
To get the data, researchers at Stone Lab sometimes have to take kayak trips around the area under study with equipment that interfaces with receivers below the water. This allows them to download data stored on receivers.
With that information in hand, researchers can then combine it with data on each individual fish – they’re assessed for age and sex when the transmitters are implanted. That allows researchers to determine where fish go between spawning seasons, whether they return to the same spawning location, or if they spawn every year or take reproductive holidays.
The data have been used in refining surgical procedures on walleye, researchers say. But they have also been shared with the Great Lakes Acoustic Telemetry Observation System, a network that helps scientists and others learn more about ongoing acoustic telemetry projects in the Great Lakes.
But the biggest job that the data perform is helping to inform management strategies that can help walleye in Lake Erie to flourish.
Spawning site fidelity – whether fish return to their home stream or reef to spawn – is one important consideration when making management decisions concerning walleye in Lake Erie. For population modeling purposes, the acoustic data help biologists to understand the origin of Lake Erie walleye as well as where they go over the course of their lives.