Stock assessment is accomplished by the Walleye Task Group (WTG) of the Lake Erie Committee’s (LEC) that is part of the Great Lakes Fishery Commission (GLFC); recommendations are also made by some universities (e.g. Michigan State University).
An Automatic Differentiation Model Builder (ADMB) statistical catch-at-age (SCAA) analysis (introduced in 2001) was performed to determine population abundance on the Lake Erie, including data from three indexes of gillnet surveys and from sport (Ohio, west and central basins; Michigan, west basin) and commercial fisheries (Ontario, west and central basins); natural mortality (M) is fixed at 0.32. Recruitment is influenced by biotic and abiotic factors; the spawner-recruit relationship is poorly known (LEWTG, 2012).

Last updated on 04 Jul 2012

Reference points are set in the management plan. B_lim at 20,000 fish is the low limit of the “low quality” population category and B_target at 40,000 fish, the upper limit of the “high quality” population category. F_{at low biomass} is set at 0.2 and F_target at 0.35(Locke et al., 2005).

Total abundance is at around 26,000 fish (LEWTG, 2012) below the long-term average and in the lower limit of the range established in the management plan (Locke et al., 2005). F is at 0.07, below F_target. The fishery is highly dependent on recruitment: poor year classes alternate with the 2003 strong year class and recently the 2007 moderate year class (SOLEC, 2011). A reduction in the stock abundance is expected to occur in 2013, to around 19,600 fish (LEWTG, 2012).

Last updated on 04 Jul 2012

During 2001-2003 a Coordinated Percid Management Strategy (CPMS) was adopted and a TAC of 3,400 tonnes established; in 2004, a TAC reduction of 30% was applied (=1,020 tonnes) (Locke et al., 2005). After the 2006 peak of 9,886 fish, the TAC has been progressively decreasing until 2010. Total catches increased progressively until 1988 reaching 10,030 fish, after then fluctuated around 4,000 – 8,000 fish but since 2001 is around 3,000 fish. After the peak at 76,700 fish in 1988, total abundance decreased until 2004 (15,850 fish) but reached the maximum peak in the following year (almost 93,000 fish); since then has been gradually decreasing. 1989 is the maximum peak for F (at 0.44), since then has been decreasing with the exception of the late 1990s period.

Last updated on 04 Jul 2012

The Walleye Management Plan was developed in 2005 to promote the stock recovery after a decreasing trend in the western and central basins in the 1960s. The main goal is to “secure a balanced, predominantly cool water fish community with walleye as a key predator in the western basin, central basin, and the nearshore waters of the eastern basin” and guarantee an abundance of around 26-40,000 fish (Locke et al., 2005). A Lake Erie Percid Management Advisory Group (LEPMAG) was created to follow the plan’s revision and assemble stakeholder groups and jurisdictions (LEWTG, 2012).

Lake Erie hosts eight fish species at risk. The gillnet bycatch is an additional threat for the recovery of the population of Lake sturgeon Acipenser fulvescens (Least Concern; 2008 IUCN Red List), especially in the west basin (ECO, 2011; Li & Jiao, 2011). The impact on the remaining Protected, Endangered and Threatened (PET) species is not known (ECO, 2011).

Other target and bycatch species are not known.

Walleye is an apex predator and this should be considered in management, to guarantee the ecosystem’s equilibrium. Is severely influenced by biotic (predation of juveniles) and mainly abiotic factors (rainfall, water temperature on SSB). The spawning habitat is being reduced due to anthropic impacts (e.g. pollution, degradation of rivers) (Locke et al., 2005).
A new Strategic Vision of the Great Lakes Fishery Commission 2011–2020 was announced recently with the aim to achieve healthy ecosystems and sustainable fisheries.

Last updated on 04 Jul 2012

Protected areas are not designated in Lake Erie.