The state of Lake Erie in 2004

Publication Type:Journal Article
Year of Publication:2009
Journal:Great Lakes Fishery Commission Special PublicationGreat Lakes Fishery Commission Special Publication
Volume:09-02
Pagination:i-vi, 1-124
Date Published:June
ISBN Number:1090-1051
Abstract:

In this first state-of-the-lake for Lake Erie, we, reporting on behalf of the Lake Erie Committee, comprising representatives of the five fisheries- management agencies of New York, Pennsylvania, Ohio, Michigan, and Ontario, gauge progress over 1999-2003 toward achievement of the fish- community goals and objectives formally established in 2003. The Lake Erie Committee (LEC) identified two broad goals, the first of which seeks "to secure a balanced, predominantly cool-water fish community with walleye as a key predator...." Walleye (Sander vitreus) remains a key predator in the western, central, and nearshore waters of the eastern basin, despite recent variability in recruitment. The cool-water fish community continues to exhibit diversity, especially recently, with valuable fisheries for walleye, yellow perch (Perca flavescens), white bass (Morone chrysops), smallmouth bass (Micropterus dolomieu), and anecdotal evidence of increases in abundance of some nearshore species. Both nearshore habitat alterations and invasive species (namely, zebra mussel (Dreissena polymorpha), round goby (Neogobius melanostomus), and sea lamprey (Petromyzon marinus)) have modified lower and upper trophic levels. In turn, the combined effects of phosphorus abatement and dreissenid mussel proliferation in the western basin has caused dramatic changes in its physical (e.g., enhanced water clarity, reduced bottom anoxia) and biological (e.g., reduced phytoplankton and zooplankton biomass, recovery of benthic mayflies) attributes. These changes, in turn, have influenced yellow perch recruitment and walleye dynamics, likely through bottom-up effects on lower trophic-level production. Even so, the round goby invasion is not without positive impacts, namely, their use by predators has opened a pathway for nutrients and energy, historically lost to zebra mussels, back to top predators. Consequently, given the myriad responses to ongoing changes to both the physical and biological attributes, challenges remain for continued progress toward the LEC's goal of a balanced, predominantly cool-water fish community with walleye as a key predator. With respect to the second broad goal, "to secure a predominantly cold-water fish community in the deep, offshore waters of the eastern basin with lake trout (Salvelinus namaycush) and burbot (Lota lota) as key predators," the LEC has made less progress. No evidence exists for natural lake trout reproduction, likely a function of continued sea lamprey predation and possibly thiamine deficiency. However, the dramatic recovery of burbot and a modest recovery of lake whitefish (Coregonus clupeaformis), although still well below historical population levels, indicate some progress toward this goal. With regard to ongoing changes in fish habitat that impede achievement of fish-community objectives, the LEC has used several strategies, including position statements (which serve to inform other agencies of fisheries-management objectives), environmental objectives (which foster communication among multiple agencies), and habitat restoration (although lagging, these targeted projects benefit fishes directly). These strategies have met with some, but limited, success. Emerging issues relevant to fish-community objectives include resurgence of the double crested cormorant (Phalacrocorax auritus) population (which argues for regional control), climate change (which argues for indicators that anticipate its effects), and ongoing ecosystem changes (which argues for an anticipatory, active research program well in tune with management needs). In our view, the state of Lake Erie is improving in some areas. Substantial attention has been paid to issues such as habitat, managing for sustainable fisheries, and lake trout rehabilitation, even though more needs to be done. What is clear from all quarters is that enhancing the lake's productive capacity and understanding how change impacts productive capacity will require cooperation and coordination across disciplines and among agencies, institutions, and stakeholders. To that end, while walleye and yellow perch continue to be managed by an interagency quota system, other warm- and cool-water species such as white bass, white perch (Morone americana), channel catfish (Ictalurus punctatus), freshwater drum (Aplodinotus grunniens) and common carp (Cyprinus carpio) are harvested by jurisdictions without an interagency management protocol, a change that likely should be made. Other issues facing the health of warm- and cool-water species include expansion of aquatic nuisance species, increased exploitation, inconsistent recruitment, increased pathogens and parasites (including sea lamprey), and loss of habitat due to human-induced effects, including changes in water levels, climate, nutrient input, and contaminant loading. In the future, LEC agencies need to do a more-effective job of transforming their position statements, environmental objectives, and targeted restoration into regional policy-level actions that meet the needs of the fish community. Additionally, the LEC agencies need to more explicitly define habitat-related activities and outcomes that would promote achievement of fish-community objectives. The dynamic nature of Lake Erie, as outlined herein, means that managers should continue their efforts in these traditional arenas and incorporate more ecosystem-based perspectives as the lake continues to change.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith