Mayo, K.R., J.H. Selgeby, and M.E. McDonald, 1997.  A Bioenergetics Modeling Approach to Top-Down Control of Ruffe in the St. Louis River, Western Lake Superior, 1991-94, U.S. Geological Survey, University of Minnesota Sea Grant Program

A Bioenergetics Modeling Approach to Top-Down Control of Ruffe in the St. Louis River, Western Lake Superior, 1991-94

Abstract
Ruffe (Gymnocephalus cernuus), exotic Eurasian percids, were accidentally introduced into the St. Louis River, western Lake Superior, in the mid-1980s. Ruffe may have negative effects on other native fish through predation on fish eggs and competition for forage and habitat. In an effort to limit the dispersal and control the increasing abundance of ruffe, a top-down control strategy using stocked predators was implemented in 1989. Bioenergetics modeling was chosen to examine the efficacy of the top-down control plan in the St. Louis River from 1991 to 1994. Five predator species, northern pike (Esox lucius), walleye (Stizostedion vitreum vitreum), smallmouth bass (Micropterus dolomieui), brown bullhead (Ictalurus nebulosus), and yellow perch (Perca flavescens), were modeled to determine their consumption of ruffe and four other native prey species, spottail shiner (Notropis hudsonius), emerald shiner (Notropis atherinoides), yellow perch (Perca flavescens), and black crappie (Pomoxis nigromaculatus). The three main predators on ruffe were brown bullhead, walleye, and northern pike. The top-down strategy had no effect in controlling ruffe abundance, and all five predator species selected the native prey and avoided ruffe. The St. Louis River is an open system that allows predators to move freely out of the system, and the biomass of the predator fish never showed the increase necessary for increased ruffe predation to occur. Due to the many complex predator-prey interactions occurring in the turbid St. Louis River environment, top-down control of ruffe in this system, by these specific predators, is probably unlikely to occur.

Entire Paper
Contact: Kathleen R. Mayo, U.S. Geological Survey, Great Lakes Science Center, Lake Superior Biological Station, Ashland, WI 54806 or mayo.kathleen@epa.gov
Keywords: Ruffe, Ecological_interactions, Predators
Product Type: Publications, Conference_proceedings
User Type: General