New Method for Studying Fish Food
Ann Arbor, MI — Researchers have used high-frequency hydroacoustics, essentially a "juiced up fish finder," to study the spatial arrangement of zooplankton in Lake Superior. These animals provide important food for young fish and native species such as lake herring, but are also notorious for being patchy and difficult to sample.
"The advantage of using a 430 kHz transducer to study zooplankton is that we can quickly assess spatial distribution and we avoid problems commonly associated with net tows, particularly the lack of fine-scale resolution," said Beth Holbrook, a researcher at the University of Minnesota Duluth.
The study correlated hydroacoustic backscatter with zooplankton dry weight from net tows so that backscatter can be converted to a biologically meaningful measure of abundance. The two sampling methods provided similar estimates of overall zooplankton dry weight biomass, but hydroacoustics provided much more detail about spatial distribution.
Original Publication Information
Results of this study "Hydroacoustic Estimation of Zooplankton Biomass at Two Shoal Complexes in the Apostle Islands Region of Lake Superior," are reported by Beth V. Holbrook, Thomas R. Hrabik, Donn K. Branstrator, Dan L. Yule and Jason D. Stockwell2 in the latest issue (Volume 32, No. 4, pp. 680-696) 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 Beth Holbrook, Department of Biology, University of Minnesota Duluth, 207 Swenson Science Building, Duluth, MN 55812; holb0028@d.umn.edu; (218) 726-7079.
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.