Biologist Bowen removes small fish from a gill net used to survey for the presence of spawning phase Eurasian ruffe. Photo by Scott Koproski, USFWS

The Alpena National Fish and Wildlife Conservation Office (NFWCO) conducted annual spring surveillance and monitoring in the Thunder Bay River of Alpena, Mich. this April to detect the presence of adult spawning Eurasian ruffe (ruffe).

All bycatch were measured and released.  Tissue samples were collected from yellow perch and walleye for a genetic study conducted by the University of Toledo - Great Lakes Genetic Laboratory to determine unique DNA markers for spawning populations of these native species.

Heather Rawlings, Scott Koproski, Adam Kowalski and Anjanette Bowen from Alpena NFWCO participated in the project.

Ruffe are an aquatic invasive species native to north central Europe that were accidentally introduced into the Great Lakes via ballast water from an ocean-going vessel.  They resemble and are related to yellow perch but do not attain a size that is desirable for sportfishing harvest and consumption and are thought to compete with native species for food and habitat resources.  Ruffe were designated an aquatic nuisance species in 1992 by the Aquatic Nuisance Species Task Force.

Ruffe were first found in the Thunder Bay area (Thunder Bay River) during monitoring efforts in 1995 and by 1999 they had become the most abundant bottom dwelling fish species captured from the Thunder Bay River.  In 2002 the Alpena NFWCO initiated this effort to remove spawning adults prior to egg release.  Spawning phase ruffe were  captured in 2002 and 2003, but have not been captured since. This survey has continued in an effort to detect the presence of ruffe that may persist in the area.