**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**

Standardization of Great Lakes Acoustic Ground-Truthing Workshop

Daniel L. Yule², Jean V. Adams³, Thomas R. Hrabik⁴, Lars G. Rudstam⁵, David M. Warner³, Brian Weidel⁶, Randall M. Claramunt⁷, Patrick M. Kocovsky⁸, Patrick J. Sullivan⁵, Larry D. Wizel⁹, and Bernard Pientka¹⁰

July 2011

² Great Lakes Science Center, Lake Superior Biological Station, 2800 Lakeshore Drive E., Ashland, WI 54806.

³ Great Lakes Science Center, 1451 Green Road, Ann Arbor, MI 48105.

⁴ Biology Department, University of Minnesota Duluth, 207 Swenson Science Building, 1035 Kirby Drive, Duluth, MN 55812.

⁵ Cornell Biological Field Station and Department of Natural Resources, Cornell University, 900 Shackelton Point Road, Bridgeport, NY 13030.

⁶ Great Lakes Science Center, Lake Ontario Biological Station, 17 Lake St., Oswego, NY 13126.

⁷ Michigan Department of Natural Resources, Charlevoix Fisheries Research Station, Charlevoix, MI 49720.

⁸ Great Lakes Science Center, Lake Erie Biological Station, 6100 Columbus Avenue Sandusky, OH 44870.

⁹ Ontario Ministry of Natural Resources, Lake Erie Management Unit, 1 Passmore Street, Port Dover, ON N0A 1N0.

¹⁰ Vermont Department of Fish and Wildlife, 111 West Street, Essex Junction, VT 05452.

ABSTRACT:

The Standardization of the Great Lakes Acoustic Ground-Truthing Workshop was held 27 September – 1 October, 2010, at the Great Lakes Science Center, Lake Erie Biological Station, Sandusky, OH. The workshop was funded by an $8,025 grant received from the Great Lakes Fishery Commission - Science Transfer Fund. A total of 65 people were invited of which 19 attended including scientists from four universities, and six state, federal and provincial agencies. The objectives of the workshop were: 1) train attendees in current methods used to apportion acoustic fish density estimates to species using ground-truth data, and 2) develop a flexible pelagic fish community simulator to test the performance of current apportionment methods through sampling artificial lake environments having known numbers of each species. The overall mission was to identify the most scientifically valid approach for assigning acoustically estimated numerical density and biomass density to fish species in the Great Lakes, and to collectively decide if standardization of apportionment methods is warranted. We developed three simulated lake fish communities analogous to lakes Superior (Lake S), Michigan (Lake M) and Ontario (Lake O) and sampled these with mock acoustic and midwater trawl gears under different levels of sampling intensity (i.e., the amount of samples that could be collected in 1, 3 and 5 nights of work with a real ship). Sampling results were then used to test performance of five apportionment methods currently in use. In general, we found that the different apportionment methods performed similarly in lakes S and M. Lake O was populated with fish such that there was minimal overlap in the vertical distribution of small rainbow smelt and alewife compared to adults of these species. In this instance, apportionment methods that utilized depth stratification (Hierarchical averaging method, Classification tree method, and the Nearest trawl with depth stratification) outperformed methods that did not (Keep it simple stupid method, and Nearest trawl method). We conclude there is little need to select a standard apportionment method for the Great Lakes, provided methods that can account for the fact that fish community composition in large lakes can vary substantially by water column depth are used. An exit survey showed attendees were generally pleased with the workshop. A manuscript describing results of objective 2 and 3 is being developed for submission to the Canadian Journal of Fisheries and Aquatic Sciences. A follow-up to our workshop for European large-lake scientists is to be held at Stockholm, Sweden, during October 2011.