**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION. The title, authors, and abstract for this completion report are provided below.  For a copy of the full completion report, or with questions, please contact the GLFC via email at stp@glfc.org or via telephone at 734-662-3209.**


Compilation and Analysis of Lake Erie Spatial Fisheries Data: A Proposal to Develop Inter-Agency Geo-Referenced Database of Fishery and Tagging Data to permit Spatial Analysis of Walleye and Yellow Perch Data


Edward S. Rutherford1, Hui-Yu Wang1 and Christine A. Geddes1


1 University of Michigan

School of Natural Resources and Environment

Institute for Fisheries Research

218 Museum Annex Bldg

1109 N. University Ave

Ann Arbor, MI. 48109-1084


May 2006




Walleye and yellow perch support important recreational and commercial fisheries in Lake Erie, and historically have been managed as one unit stock.  Although spatial data on fishing activity (effort & harvest) and fish behavior (tagging) have been collected by each agency on their Lake Erie fisheries for many years, no comprehensive analysis or summary of spatial and geographical stock distribution exists for Lake Erie walleye and yellow perch.  The objectives of this study were to 1) assemble spatial data on fishing effort and harvest, tag recaptures, survey data and pertinent habitat data into a central, shared, spatial database that supports queries and statistical analyses; 2) Analyze the data and map patterns of fishing and fish density distributions; 3) Combine walleye catch rate data with tag recapture data to determine monthly stock-specific exploitation rates within 10-minute grids by angler and/or commercial fisheries; 4) make recommendations for improving data collection; 5) relate habitat information to fish distribution, relative abundance and movement.  We assembled spatial data on fishing effort and harvest, walleye tag recaptures, agency survey data and pertinent habitat data into a central ACCESS database and ArcGIS framework that supports queries, statistical analysis, and mapping.  Analyses of tag recapture data and modeling of walleye growth suggested multiple walleye stocks exist that differ in growth and migration patterns.  Walleye tag return data indicated that in summer, western basin (WB) walleyes migrated to the central (CB) and eastern basins (EB) of Lake Erie and north to Lake St. Clair and southern Lake Huron, while fish in the CB and EB basins of Lake Erie and in Lake St. Clair were primarily resident. Temporal changes in sport and commercial catch per unit effort (CPUE) for walleyes confirmed movements suggested by tag return data. CPUE was highest in the WB in spring to early summer, and then shifted to the CB in late summer and fall. Mean length of recaptured walleyes, regardless of origin, was greater in the CB and EB of Lake Erie than in the WB of Lake Erie or Lake St. Clair. The migratory WB walleyes were larger and contained a higher proportion of females than resident WB walleyes. The six largest WB stocks that expressed variable migratory behaviors and population parameters could be assigned into three super groups: a group with largest mean length at tagging, a group with very low percentages of females and small mean length at tagging, and a group with low percentages of resident fish and high percentages of females. Summer temperatures in the WB often exceeded the optimal temperature (20-23C) for growth of large walleye, and the migration of walleyes to the east might have been a size-dependent response to warm summer temperatures that raised metabolic costs. Cooler temperatures and attraction to soft-rayed forage fishes likely contributed to an energetically favorable foraging habitat in the CB and EB that attracted large walleyes. We tested this hypothesis by comparing walleye movement patterns to habitat quality as indexed by a spatially-explicit growth rate potential (GRP) model.  The GRP model was configured using forage fish gillnet CPUE and water surface temperature data derived from AVHRR satellite imagery.  Walleye GRP patterns were compared with Ontario MNR experimental gillnet survey data that indexed relative abundance, and with the observed walleye movement, growth, and life history patterns.  Results demonstrated that growth rates of young (<age 3 yrs) walleye were highest in the WB, but growth rates of older walleye were higher in the CB and EB.  Bioenergetic growth rate potential (GRP) of age-2 walleye was highest in the WB, where age-2 walleye densities were highest.  Predicted GRP of older walleye did not vary among basins, in contrast to growth and migration patterns.  Consequently, older Lake Erie walleyes may not select habitat to optimize growth, but to lower metabolic costs.  Walleye in the WB and CB were distributed in water columns of high GRP, whereas in the EB walleye favored areas with warm temperatures over areas of high GRP.  In contrast to walleye, temporal and spatial variability in yellow perch density and catch rate patterns did not indicate stock movement among basins.  Surveys indicated age-0 and older perch were found in high concentrations throughout Lake Erie, with highest densities in WB, followed by CB and EB.  Ontario fall gillnet surveys CPUE (#/net) and sport angler CPUE data (# fish/hr) also indicated relative abundance of older perch was higher in WB and CB compared to EB.  However, biomass CPUE of commercial gillnet fishers indicated highest catch rates were made in CB, followed by WB and EB.  Seasonal trends in commercial gillnet and sport CPUE data suggested highest catches were made in spring and fall.  Neither sport nor commercial CPUE trends indicated yellow perch movement across basins.  Our analysis of yellow perch spatial and seasonal CPUE trends are supported by earlier tagging studies of yellow perch in western and central Lake Erie indicating yellow perch move less 30 miles (48 km) over a season.  Analysis of yellow perch habitat preference, as indicated by high densities, suggest that in WB perch were found over shallow depths <15m, with predominantly low gradient mud bottoms of high Hexagenia spp density.  In CB, perch were predominantly found over low gradient mud bottoms in depths 13-33m.  In EB, highest perch densities were found over mud and sand-gravel substrates of intermediate gradient at depths from 20 to 40m.