Smallmouth bass growth increased following invasion of Lake Erie by the round goby

Ann Arbor, MI — Although the invasive round goby has negatively affected many native species in the Great Lakes, it has become an important food source for many predators. The diet of smallmouth bass, one of the most important sport fishes in Lake Erie, changed substantially following the invasion of Lake Erie by the round goby. The dietary changes were associated with changes in smallmouth bass growth.

To investigate the effects of round goby on smallmouth bass, researchers Dr. Derek Crane (Coastal Carolina University) and Donald Einhouse (New York State Department of Environmental Conservation) analyzed diet and length-at-age data from the NYSDEC’s long-term warm water fish survey.

The researchers found that crayfish were the most common prey of smallmouth bass prior to invasion of round goby (observed in 53.5% of diets). However, round goby became the dominant prey of smallmouth bass shortly after its invasion (observed in 73.3% of diets). Results from the study also showed that growth of smallmouth bass, particularly young smallmouth bass, increased substantially following the shift from a crayfish- to a round goby-dominated diet. The researchers observed that lengths of smallmouth bass aged 2-4 increased by 11-15% following round goby invasion.

“This case study demonstrates how aquatic invaders can rapidly change population characteristics of native predators and the importance of long-term surveys for understanding how invasive species are affecting native sport fishes in the Great Lakes” states lead author Dr. Derek Crane. Although smallmouth bass may have benefitted from increased growth, Crane cautions that “the smallmouth bass-round goby dynamic is not fully understood, and while round goby provide a good food source they have the potential to negatively affect smallmouth bass populations through predation on smallmouth bass eggs and spread of disease.”

Original Publication Information

Results of this study, "Changes in growth and diet of smallmouth bass following invasion of Lake Erie by the round goby," are reported by Derek P. Crane and Donald W. Einhouse in Volume 42, Issue 2 of the Journal of Great Lakes Research, published by Elsevier, 2016.

Contacts

For more information about the study, contact Dr. Derek Crane, Department of Biology, Coastal Carolina University; [email protected].

For information about the Journal of Great Lakes Research, contact Stephanie Guildford, Scientific Co-Editor, Large Lakes Observatory, University Minnesota Duluth, 2205 East Fifth Street, Duluth, Minnesota, 55812-2401; [email protected]; (218) 726-8064.