Crews with four Michigan research vessels are beginning annual surveys of Great Lakes fish populations.
The Department of Natural Resources says the studies produce information for conserving and managing the lakes' fish, which support a multi-billion-dollar tourist economy.
The agency's newest research vessel is the Tanner, launched last year. Its team focuses on lake trout and walleye in Lake Huron, plus broader fisheries assessments in Saginaw Bay and the St. Marys River.
The Lake Char is deployed on Lake Superior, where it helps determine lake trout harvest quotas and provides insights on damage caused by parasitic sea lamprey.
The vessel Channel Cat studies fish in Lake Erie and Lake St. Clair, while the vessel Steelhead covers Lake Michigan.
Officials say visitors are welcome when the vessels are in port.
