Zebra and Quagga Mussels: Fish Predation on Quagga Mussels

Project ID: 9508
Principal Investigator: Cathy Karp
Research Topic: Ecosystem Needs
Priority Area Assignments: 2010 (Zebra and Quagga Mussels), 2011 (Zebra and Quagga Mussels), 2012 (Zebra and Quagga Mussels), 2013 (Zebra and Quagga Mussels)
Funded Fiscal Years: 2010, 2011, 2012 and 2013
Keywords: None

experimental cage (6'X6'X8')to house either fish with mussels or mussels alone<br>[<a href='imagepop.cfm?id=9508|482' target='_blank' style='color:#bbb'>view information</a>] experimental cage deployed in Partner's Point cove<br>[<a href='imagepop.cfm?id=9508|484' target='_blank' style='color:#bbb'>view information</a>] bricks were suspended in Lake Havasu the previous year to become colonized with quagga mussels for the predation experiments<br>[<a href='imagepop.cfm?id=9508|486' target='_blank' style='color:#bbb'>view information</a>]

Project Abstract

Quagga mussels, Dreissena bugensis, from Eurasia are widespread in the Colorado River drainage and associated waterworks, and are impacting state and federal water delivery operations. One potential mussel suppression agent is predation by redear sunfish, Lepomis microlophus. In aquaria experiments, 85.7 percent of juvenile and adult redear sunfish, Lepomis microlophus, and bluegill, L. macrochirus, were found to consume quagga mussels. Predated mussels were crushed and shell material was regurgitated and defecated. Mean mussel size consumed was positively correlated with fish size (r=0.7, P=0.000). In 21 field enclosure experiments, redear sunfish significantly reduced areal mussel density (P = 0.0193, Wilcoxon Rank Sum Test) by as much as 25.3 percent. However, this decrease was not observed in 6 of 13 fish enclosures which suggests that redear sunfish may consume other prey if available. Mussel density did not decline in enclosures without fish (<1 percent) and new mussel settlement was minimal. These experiments suggest that redear sunfish, and possibly other fish species, may help to control but not eliminate quagga mussel in areas where the two species co-occur.

Contributing Partners

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Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Summary of Laboratory and Field Experiments to Evaluate Predation of Quagga Mussel by Redear Sunfish and Bluegill (final, PDF, 2.4MB)
By Cathy Karp
Research Product completed on September 23, 2014

Quagga mussels, Dreissena bugensis, from Eurasia are widespread in the Colorado River drainage and associated waterworks, and are impacting state and federal water delivery operations. One potential mussel suppression agent is predation by redear sunfish, Lepomis microlophus. In aquaria experiments, 85.7 percent of juvenile and adult redear sunfish, Lepomis microlophus, and bluegill, L. macrochirus, were found to consume quagga mussels. Predated mussels were crushed and shell material was reg

Do Redear Sunfish Eat Quagga Mussels? (final, PDF, 924KB)
By Cathy Karp
Publication completed on September 30, 2015

This bulletin summarizes the research results and potential application to Reclamation's mission.

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Last Updated: 6/22/20