10 Billion Round Gobies In Western Lake Erie
Ann Arbor, Mich. — Scientists have estimated the population of round gobies in western Lake Erie to number 10 billion in 2002. Using a remotely-operated underwater video system (ROV), a team of scientists from the Ontario Ministry of Natural Resources and the University of Windsor enumerated round gobies in a variety of natural habitats between June and October to come up with the estimate.
Round gobies are an invasive fish that arrived in the Great Lakes basin in 1990 and quickly spread to all five of the Great Lakes and many connecting waterways. These fish compete with native fishes for food and habitat, consume eggs and young of native fishes, and have altered energy pathways (feeding relationships) including the movement of contaminants.
A number of research studies have been undertaken or are presently underway to evaluate some of these impacts, but to date scientists have been challenged to estimate the actual number of round gobies because of the bottom dwelling nature of these fish, including their preference of rocky areas that are hard to sample.
To address this challenge, these scientists combined the use of an ROV with substrate maps to describe habitat preference and seasonal movements of different ages of round gobies which, when combined, provide a comprehensive estimate of the total number of round gobies in western Lake Erie.
Description of this technique for estimating the abundance of round gobies in natural habitats will enable scientists in western Lake Erie and elsewhere to provide better predictions of the impact of round goby populations on native fish and other biota.
Original Publication Information
Results of this study "Comparison of methods needed to estimate population size of round gobies (Neogobius melanostomus) in western Lake Erie" are reported by Timothy B. Johnson, Melissa Allen, Lynda D. Corkum, and Victoria A. Lee in the latest issue (Volume 31, No. 1, pp. 78-86) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2005.
Contacts
For more information about the study, contact Tim Johnson, Ontario Ministry of Natural Resources, Lake Erie Fisheries Station, 320 Milo Road, Wheatley, Ontario, N0P 2P0; tim.johnson@mnr.gov.on.ca; (519) 825-7316.
For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; marlene.evans@ec.gc.ca; (306) 975-5310.
Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.
