Reassessment of the predatory effects of rainbow smelt on ciscoes in Lake Superior

Transactions of the American Fisheries Society
By: , and 



Evidence from small lakes suggests that predation on larval ciscoes Coregonus artedi by nonnative rainbow smelt Osmerus mordax can lead to cisco suppression or extirpation. However, evidence from larger lakes has led to equivocal conclusions. In this study, we examine the potential predation effects of rainbow smelt in two adjacent but contrasting embayments in Lake Superior (Thunder and Black bays, Ontario). During May 2006, we sampled the ichthyoplankton, pelagic fish communities, and diet composition of rainbow smelt in both bays. Using acoustics and midwater trawling, we estimated rainbow smelt densities to be 476 ± 34/ha (mean ± SE) in Thunder Bay and 3,435 ± 460/ha in Black Bay. We used a bioenergetics model to estimate the proportion of cisco larvae consumed by rainbow smelt. Our results suggest that predation by rainbow smelt accounts for 15–52% and 37–100% of the mortality of larval ciscoes in Thunder and Black bays, respectively, depending on the predator feeding rate and the scale of predator–prey overlap. We also examined the sensitivity of past conclusions (based on 1974 field collections) to assumptions of temporal overlap between rainbow smelt and larval ciscoes and estimates of rainbow smelt abundance derived from bottom trawl samples. After adjusting these parameters to reflect current understanding, we found that the previous predation estimates may have been conservative. We conclude that rainbow smelt may have been a more important contributor to the demise and slow recovery of ciscoes in Lake Superior than previously thought.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Reassessment of the predatory effects of rainbow smelt on ciscoes in Lake Superior
Series title Transactions of the American Fisheries Society
DOI 10.1577/T08-131.1
Volume 138
Issue 6
Year Published 2009
Language English
Publisher Taylor & Francis
Publisher location Philadelphia, PA
Contributing office(s) Great Lakes Science Center
Description 17 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Transactions of the American Fisheries Society
First page 1352
Last page 1368
Other Geospatial Lake Superior
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