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475 Managing Inherent Complexity for Sustainable Walleye Fisheries in Lake Erie Edward F. Roseman, Richard Drouin, Marc Gaden, Roger L. Knight, Jeffrey Tyson, and Yingming Zhao In Lake Erie, Walleye (Sander vitreus vitreus) is king. The naturally occurring species is the foundation of commercial fishing operations on the Canadian side of the lake and is a much-prized sportfish on the U.S. side (Lloyd and Mullen 1991; Lichtkoppler 1997; Lichtkoppler et al. 2008). The species provides billions of dollars to the economies of New York, Pennsylvania, Ohio, Michigan, and the province of Ontario each year (Lichtkoppler 1997; Lichtkoppler et al. 2008) and is part of the culture of local communities. Currently, 188 commercial licenses exist in Ontario’s Lake Erie waters, employing thousands of people on boats and on shore. Recreational fishing attracts more than one million anglers annually to the four U.S. states that border the lake and is the backbone of a thriving tourism industry, including thousands of charter boats, bait shops, motels, and other local businesses. Together, commercial and recreational harvests have averaged about 4.7 million fish annually since 1975 (Walleye Task Group [WTG] 2008). Management of Lake Erie Walleye fisheries is complex and takes place in an inter-jurisdictional setting composed of resource agencies from the states of Michigan (Michigan Department of Natural Resources and Environment [MDNRE]), Ohio (Ohio Department of Natural Resources [ODNR]), Pennsylvania (PennsylvaniaFishandBoatCommission[PFBC]),andNewYork(NewYorkDepartmentofEnvironmental Conservation [NYDEC]) and the province of Ontario (Ontario Ministry of Natural Resources [OMNR]). The complexity of Walleye management is exacerbated by interactions among environmental and ecological changes in Lake Erie, complex life-history characteristics of the species, public demand for Walleye, and cultural/governance differences among managing groups and their respective constituents. Success of future management strategies will largely hinge on our ability to understand these inherent complexities and to employ tactics that successfully accommodate stock productivity and human demand in a highly dynamic environment. This chapter reviews the history of Lake Erie Walleye management, outlines the multi-jurisdictional process for international management of Walleye, and discusses strategies to address challenges facing managers. Edward F. Roseman et al. 476 Overview of the Lake Erie Environment From its glacial origin nearly twelve thousand years ago, Lake Erie is situated in North America between the 41 and 43 degree parallels and the 79 to 83 degree meridians, extending slightly northeast to Niagara Falls, Ontario, from its southwestern edge near Toledo, Ohio. It is the eleventh largest freshwater lake in the world by volume (484 km3), but the shallowest of the Laurentian Great Lakes (19 m average depth). Lake Erie has unique bathymetry, with three geomorphologically distinct basins, known as the west, central, and east basins (fig. 1). Given its geographical and bathymetrical orientation, prevailing winds from the SW-W direction or, conversely, storm winds from the NE quadrant, typically travel the longest stretches of the lake, making it hydrologically responsive to winds. Seiches, gyres, and varying surface/bottom circulation patterns are substantial and common in Lake Erie. More than 90 percent of the annual water inputs to Lake Erie come from the Detroit, Maumee, and Sandusky Rivers, combined. The Niagara River is the major outflow connecting Lake Erie with Lake Ontario and maintains relatively stable water levels in Lake Erie (Bolsenga and Herdendorf 1993). Lake Erie is biologically productive, due to its latitude (more than two hundred frost-free days per year, on average), nutrient-rich watershed (67 percent of total land use is agriculture, other Great Lakes range 3–44 percent), and short water retention time (2.6 years; Bolsenga and Herdendorf 1993; Fuller et FIG. 1. Bathymetry and basins of Lake Erie. Contour intervals are in meters. WB = western basin, CB = central basin, and EB = eastern basin. SUSTAINABLE WALLEYE FISHERIES IN LAKE ERIE 477 al. 1995). The west basin is the shallowest, warmest, most turbid, and most homothermic of the three basins, whereas the east basin is the deepest, coldest, clearest, with thickest hypolimnion of all basins. The central basin is intermediate to the west and east basins in essentially every attribute. Accordingly, a west-to-east productivity gradient exists with eutrophic conditions being typical of the west basin and oligotrophic conditions in the east basin (table 1). Although the Lake Erie watershed comprises many tributaries (table 2), particularly on the south side, only a few meet the flow criteria of Eshenroder (2003) TABLE 1. Environmental Features that Affect Walleye (Sander vitreus vitreus) Fisheries in Lake Erie ATTRIBUTE WEST BASIN CENTRAL BASIN EAST BASIN...

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