During this five-year reporting period (2000-2004), progress was made in Lake Huron towards achieving the objective of a fish community dominated by top predators, with self-sustaining populations of lake trout (Salvelinus namaycush) playing a prominent role. Some examples include increased representation of wild-born lake trout in surveys of adult lake trout, capture of wild young-of-the-year lake trout, and very large reductions in the abundance of the exotic alewife (Alosa pseudoharengus), a species that likely impedes the rehabilitation of lake trout and other native species. Sea lamprey (Petromyzon marinus) abundance also decreased, which is a benefit for lake trout rehabilitation and for overall usable fish production. On the other hand, concerns have arisen that overall fishery productivity may have declined since 1999, the end of the previous reporting period. While the objective of a diverse salmon and trout fishery has been partially met, the contribution of the once-dominant Chinook salmon (Oncorhynchus tshawytscha) has declined dramatically. Overall yield objectives for both salmonid and non-salmonid species appear to be unrealistic. Predators are showing indications of substantial food limitation with overall prey-fish abundance substantially lower in 2004 than in 1999. Substantial uncertainty exists regarding the nature of the productivity changes and the role of dreissenid mussels and other exotic species in these changes. The yield of lake whitefish (Coregonus clupeaformis), the dominant commercial species, declined from 1999 to 2004 to levels just below the yield target in the fish-community objective for all coregonines combined. Given the changes in lower trophic levels and the downward trend in lake whitefish yield, the target for coregonine yield, of which lake whitefish is the major component, is likely unsustainable. Lakewide walleye (Sander vitreus) yield remained near 35% of the yield target within the fish-community objective. Large year-classes of juvenile walleye were produced in Saginaw Bay in 2003 and 2004. How strongly these year-classes will contribute to fishery yield and whether juvenile abundance has surged elsewhere remains to be determined. Yellow perch (Perca flavescens) yield has declined to levels not seen since the 1920s for reasons that are not well understood. However, strong year-classes were observed in 2003 in the main basin. The lake sturgeon remains listed as a Threatened Species in Michigan, and as a Species of Concern in Ontario waters. Although its population increased, much progress is needed before the listings can be removed. Various escocids, centrarchids, and other nearshore species continue to contribute to diverse fishing opportunities. Species diversity remains essentially unchanged since 1999 with the notable reappearance of the shortjaw cisco (C. zenithicus), which was thought to be extirpated at the time of the 1999 report. An increasing number of studies of genetic stock structure have been conducted or are under way, but these projects are not sufficient to fully evaluate progress towards genetic-diversity objectives. In addition to exotic species that may be influencing the food web, invasive plant species are increasingly dominating wetlands and other nearshore areas and are potentially influencing the value of these areas as fish nursery habitat or as areas for recreation. More information is needed to assess progress towards habitat objectives. The foremost recommendation stemming from this report is to reevaluate the use of yield as the major metric for defining fish-community objectives. Increased research is also needed to better understand how lower trophic-level processes impact fish-community structure and production. Other recommendations include maintaining effective sea lamprey control, identifying high-priority habitat in need of protection, and directing more management towards native species restoration.
; Habitats; Recreation areas; Food; Community relations; Fish; Sturgeon; Food webs; Food plants; Predators; Habitat; Species diversity; Trophic levels; Introduced species; Nursery grounds; Objectives; Productivity; Prey; Threatened species; Fishing; Fisheries; Restoration; Lakes; Abundance; Community structure; Rehabilitation; Native species; Trout; Yield; Year class; Inland waters; Fisheries management; Population; Juveniles; Rare species; Salmon; Surveys; Commercial species; Invasive plants; Fish hatcheries; Endangered & extinct species; Indigenous species; Mussels; Genetic diversity; Food chains; Biodiversity; Invasive species; Sander vitreus; Petromyzon marinus; Alosa pseudoharengus; Coregonus clupeaformis; Coregonus zenithicus; Oncorhynchus tshawytscha/