Burbot Population Declining in Apostle Islands Region
Ann Arbor, MI — A 30-year study by the Wisconsin Department of Natural Resources found burbot declining in abundance in the Apostle Islands region of Lake Superior.
"The decline is related to changes in the fish community and not sea lamprey predation, fishing mortality, or habitat loss," says Stephen Schram, Lake Superior Fisheries Supervisor with the Wisconsin Department of Natural Resources. "Increased numbers of lake trout have likely contributed to the decline in burbot through predation and/or competition for food resources," Schram adds.
Burbot are native predators in Lake Superior whose ecological role is poorly understood by fishery researchers. Burbot are incidentally caught by commercial fishers but then discarded due to their low market value.
"If we release pheromones into or near traps, we can lure the fish, but first we need to collect and identify these chemical cues," explains Jared Fine, who recently earned his Ph.D. at the University of Minnesota. "Now, we have developed a practical means to accomplish this."
Ontario Ministry of Natural Resources Research Scientist Dr. Timothy B. Johnson analyzed burbot consumption as part of the study. "The diet of burbot shifted progressively from invertebrates to fish as size increases," states Johnson. Also, Johnson found the burbot population from Apostle Islands consumed considerably less prey (0.13 to 3.54 kg/ha) than did those in Green Bay (15.8 kg/ha), or did other predators in western Lake Superior (5.2 to 22.4 kg/ha).
Original Publication Information
Results of this study "Burbot Consumption and Relative Abundance in the Apostle Islands Region of Lake Superior," are reported by Stephen T. Schram, Timothy B. Johnson and Michael J. Seider in the latest issue (Volume 32, No. 4, pp. 798-805) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2006.
Contacts
For more information about the study, contact Stephen Schram, Wisconsin DNR, 141 S. 3rd Street, P.O. Box 589, Bayfield, WI 54814; Stephen.schram@dnr.state.wi.us; (715) 779-4035-12.
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; editor@iaglr.org; (608) 692-1076.
Links
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.