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A bioenergetics modeling evaluation of top-down control of ruffe in the St. Louis River, western Lake Superior

Journal of Great Lakes Research

By:
, , and
DOI: 10.1016/S0380-1330(98)70824-X

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Abstract

Ruffe (Gymnocephalus cernuus), were accidentally introduced into the St. Louis River estuary, western Lake Superior, in the mid 1980s and it was feared that they might affect native fish through predation on eggs and competition for forage and habitat. In an effort to control the abundance of ruffe and limit dispersal, a top-down control strategy using predators was implemented in 1989. We used bioenergetics modeling to examine the efficacy of top-down control in the St. Louis River from 1991 to 1994. Five predators--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). Although predators ate as much as 47% of the ruffe biomass in 1 year, they were not able to halt the increase in ruffe abundance. The St. Louis River is an open system that allows predators to move freely out of the system, and the biomass of managed predators did not increase. A selectivity index showed all five predators selected the native prey and avoided ruffe. The St. Louis River has several predator and prey species creating many complex predator-prey interactions; and top-down control of ruffe by the predators examined in this study did not occur.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
A bioenergetics modeling evaluation of top-down control of ruffe in the St. Louis River, western Lake Superior
Series title:
Journal of Great Lakes Research
DOI:
10.1016/S0380-1330(98)70824-X
Volume
24
Issue:
2
Year Published:
1998
Language:
English
Contributing office(s):
Great Lakes Science Center
Description:
p. 329-342
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Great Lakes Research
First page:
329
Last page:
342