State of the Lake
Lake Superior as a whole is one Great Lake that continues to maintain much of its aquatic and terrestrial habitat intact. However, significant degradation has historically occurred in some locations across the basin. While significant progress on habitat improvement such as dam removals, culvert replacement, and riparian corridor restoration was achieved during this reporting period, significant impairments still exist, especially mining waste deposits around the Keweenaw Peninsula. Fish consumption advisories for legacy contaminants continue to be in place in most jurisdictions and new contaminant advisories (e.g. PFAs) are an emerging concern.
Lake Superior continues to maintain a diverse prey fish community comprised primarily of indigenous species. While prey fish abundance is low relative to previous reporting periods, prey species continue to be self-sustaining. Cisco recruitment was a concern during the reporting period, but cisco continued to support a viable commercial fishery in several jurisdictions and were reported in the diets of native fishes.
Lake trout declined to extremely low levels in Lake Superior due to commercial overfishing, accelerated by the invasion of sea lamprey. Rehabilitation began with sea lamprey control, allowing additional management efforts to be effective, such as strict harvest regulations and stocking. By 1996, the Lake Superior Committee (LSC) was able to substantially reduce stocking due to increased abundance of naturally reproducing lake trout populations. Currently, abundance of naturally reproduced lake trout is estimated to be at or above what are considered the best estimates of abundance prior to sea lamprey invasion. Because of this, the LSC believes the lake trout population is restored, and has achieved the 2003 Fish Community Objective of a “genetically diverse self-sustaining populations of lake trout that are similar to those found in the lake prior to 1940, with lean lake trout being the dominant form in nearshore waters, siscowet lake trout the dominant form in offshore waters, and humper lake trout a common form in eastern waters and around Isle Royale.”
Lake Superior continued to support production of lake whitefish at levels that support commercial harvest at or above the range of harvest values from 1990-1999 during the reporting period. During the reporting period, recruitment of lake whitefish increased and average recruitment levels were higher than the previous reporting period. Lake whitefish are expected to continue at these levels barring any significant change in regulatory or ecosystem processes.
While information on Lake Superior walleye is less robust, Lake Superior continues to support self-sustaining stocks of walleye at a number of locations across their historic range. Rehabilitation of some stocks (e.g. Black Bay, ON) is ongoing but positive progress is being made.
The number of self-sustaining populations of lake sturgeon in Lake Superior is increasing due to rehabilitation efforts and, in Wisconsin waters, provide for limited harvest opportunities. Full lake sturgeon rehabilitation may be challenging given that habitat limitations would require tradeoffs with current harbor uses (shipping and marinas) and with sea lamprey control (barrier dams).
Lake Superior brook trout continue to show mixed progress towards rehabilitation. Several stream populations of brook trout continue to persist in historic locations, with some doing relatively well, however, coaster brook trout continue to show limited signs of rehabilitation in Lake Superior proper in most locations. Coaster brook trout and stream resident brook trout are genetically similar, and it appears coaster brook trout are a life-history variant that moves into Lake Superior to feed and therefore grow larger. Currently, stream resident populations are being rehabilitated through in-stream habitat improvements. This coupled with conservative harvest regulations on Lake Superior, for brook trout that venture into the lake, is likely to improve the number of large brook trout captured in Lake Superior.
8.0 Pacific Salmon, Rainbow Trout, and Brown Trout
Lake Superior continues to support self-sustaining populations of Pacific salmon, rainbow trout, and brown trout. However, populations are augmented by stocking in some locations. These populations are meeting fishery objectives in that they appear to be compatible with restoration and management goals established for indigenous fish species. Stocking levels during the reporting period were the lowest on record.
Invasive sea lamprey populations must be controlled to prevent negative impacts on desirable fish stocks. Control efforts during the reporting period have not reduced sea lamprey abundance to target levels and fish community impacts continue to be seen. Estimates suggest that sea lamprey mortality continues to exceed harvest mortality in many locations in Lake Superior. Balancing sea lamprey control with habitat improvements, i.e. barrier removals, and resistance to lampricide treatments is important to maintaining fish populations at their current levels.
Lake Superior continues to see the introduction and spread of non-indigenous nuisance species through multiple vectors. Outside of targeted sea lamprey control, no programs are in place to reduce or eliminate non-indigenous nuisance species.
While data availability to assess Lake Superior species diversity is limited, Lake Superior continues to support four recognized lake trout forms (lean, siscowet, humper and redfin), and has retained its original cisco fauna, unlike the other Great Lakes. In addition, where assessments of other native prey species exist, populations appeared to be stable but lower in the past two reporting cycles as compared with the 1990s, which is likely the result of increased predator populations.
1.0 Salmonine (Salmon and Trout)
A diverse salmon and trout predator community comprised of Chinook salmon, coho salmon, rainbow trout, brown trout and lake trout is maintained at a level of abundance supporting vibrant recreational and charter sport fisheries, and tribal commercial and subsistence fisheries. Progress was observed toward establishing self-sustaining lake trout populations after multiple decades of rehabilitation stocking.
The offshore prey fish community rebounded from record lows in 2015-16 to more moderate levels during the current reporting period and supported a healthy predator fish community and fishery. The prey fish community remains moderately diverse, though dominated by naturalized populations of alewife and round goby. Biomass of native bloater increased relative to biomass estimates made during the previous decade.
Self-sustaining populations of nearshore fishes comprised of yellow perch, walleye, smallmouth bass, pike and panfish provide quality fishing opportunities for Lake Michigan recreational anglers, especially in Green Bay, and opportunities for tribal commercial and subsistence fishing for walleye and yellow perch. Most species are meeting harvest expectations. One exception is yellow perch, which had dramatic population declines throughout the main lake basin in the mid-1990s and remain at low levels compared to highs in the 1980s. At this time, yellow perch support limited commercial fishing only in Green Bay.
4.0 Benthivore (Bottom Feeding Fish)
Benthic fishes, including lake whitefish, round whitefish, lake sturgeon, suckers, and burbot are maintaining populations in Lake Michigan. However, many lake sturgeon populations require long-term rehabilitation efforts (streamside rearing and stocking) and lake whitefish populations in the main basin are performing at levels well below management goals.
Invasive sea lamprey population abundance must be controlled to prevent negative impacts on desirable fish stocks. Control efforts during the current reporting period have been highly successful in reducing the abundance of adult lamprey and the rate of lamprey marking on large lake trout.
A fish community of moderate richness, diversity and comprised of native and non-native fish species is maintained in the nearshore waters of southern Lake Michigan and Green Bay, areas targeted for monitoring. The fish community remained stable during the reporting period and likely contributed to the overall biological integrity and health of the Lake Michigan ecosystem.
Development of Environmental Principles and Priorities has identified important functional habitats at specific geographic locations for protection and restoration actions to improve production of desired fish species. Despite substantial reductions in fish contaminant levels in fillets of many sizes and species of fish, consumption advisories are still necessary across all Lake Michigan jurisdictions.
1.0 Salmonine (Salmon and Trout)
Positive progress was observed toward re-establishing lake trout as the dominant salmonine and anadromous species have been maintained as an important contributor to the fishery. However, the potential for the target annual yield which can be sustained remains adversely affected by invasive species.
2.0 Percid (Walleye and Perch)
Measures of lakewide walleye harvest are approaching the historical observed range and are currently supporting quality fisheries, suggesting efforts to reestablish and maintain walleye have been met. Yellow perch harvest remains depressed relative to historical records.
3.0 Esocid (Northern Pike and Muskellunge)
While yield has not been quantified throughout the basin, northern pike and muskellunge both remain present and northern pike are a prominent component of nearshore and embayment fish communities and fisheries.
Channel catfish relative abundance, as indexed by catch rates of biomass sampled, has remained stable or is increasing in all areas of the lake they can be expected to be found.
5.0 Coregonine (Lake Whitefish and Cisco)
Yield has varied considerably in both quantity and composition over the past century. Since 2000, commercial harvest has consisted almost entirely of lake whitefish and this measure has been declining over the same time period as production and survival of young lake whitefish has been adversely impacted by the ecosystem and food web changes associated with establishment of dreissenid mussels. Conversely, cisco remain common and appear to be stable in northern Lake Huron, seemingly less affected by dreissenid impacts. Efforts to restore cisco in southern Lake Huron, which traditionally supported a robust fishery, have been ongoing since 2018 and the first hatchery-produced adults were recaptured in 2022, which is an encouraging step towards restoration. Additional time is needed to determine if these fish can successfully reproduce in southern Lake Huron.
6.0 Centrarchid (Bass and Sunfish)
Both largemouth and smallmouth bass have remained a prominent recreational presence in nearshore areas and embayments around the lake. Other centrarchid species have also been maintained as an important component of nearshore fish communities.
The number of self-sustaining lake sturgeon populations around Lake Huron has remained relatively static over the current reporting period. However, reintroduction efforts into waters where previously extirpated, specifically Saginaw Bay, have been successful with an increasing presence of juvenile fishes; some of these fish will be approaching maturation at the end of the next reporting cycle.
While prey fish diversity is near target measures, total biomass of both native and non-native groups remains depressed. The redirection of energy flow through dreissenid mussels on the lake bottom has facilitated expansion of round goby, which is not effectively sampled with traditional survey gears but is suspected to now comprise a significant portion of current available prey biomass within Lake Huron.
Invasive sea lamprey control is essential to supporting desired fish stocks, restoration of native fishes, and all other fisheries management goals and objectives in Lake Huron. The increasing trend in the adult sea lamprey index despite meeting the reduced lake trout wounding rate is concerning. This trend implies increased parasitic losses of desired fish biomass has occurred during the reporting period and could further influence the subsequent reporting period by increased capacity for sea lamprey reproduction.
Native species richness and overall biomass has remained stable or has increased across various parts of Lake Huron and represents positive progress towards native species restoration.
Research efforts indicate the genetic integrity of aquatic organism populations in Lake Huron have been adequately maintained and fish stocks are diverse at the genetic level.
Several habitat restoration and enhancement projects occurred during the reporting period and these efforts continue to support and benefit recovery of native species. However, these projects may not offset ongoing broadscale anthropogenic effects on habitat and water quality which continue to impact the Lake Huron aquatic community and its users.
1.0 Intensively Managed Species
- Walleye
- Yellow Perch
- White Bass
- Lake Whitefish
- Sea Lamprey
Intensively managed species support economically important commercial fisheries and harvest-oriented sport fisheries. Invasive sea lamprey, which must be controlled to prevent negative impacts to fish stocks, is also considered an intensively managed species. Management decisions for these species are informed through monitoring programs and statistical models designed to estimate population size, safe harvest limits, or control objectives. In many cases, species-specific lakewide management plans drive annual decision making. The goal of this style of management is long-term sustainability of economically important fish stocks.
- Black Bass
- Muskellunge
- Rainbow Trout
These species support economically important localized sport fisheries that are not commercially harvested. Lakewide objectives drive the management of these species, with management decisions based on annual monitoring programs and agency-specific regulations such as seasons and bag limits.
- Lake Trout
- Lake Sturgeon
- Cisco
- Sauger
These species have potential ecological or fishery importance but were extirpated or exist at a small fraction of their former abundance. Restoration or preservation programs are in place for some species, with the goal of restoring naturally reproducing populations or protecting populations that still exist in the Lake Erie Basin.
Prey Fish
Prey-fish include largely unfished and unmanaged populations that are necessary to support sustainable commercial and sport fisheries. Monitoring prey-fish species composition and abundance along with predator growth and condition promotes a better understanding of predator-prey dynamics and fishery performance.
- Lower Trophic Levels
- Habitat
Environmental objectives encompass a range of abiotic factors, such as trends in productivity and status of critical fish habitat, that are necessary for the long-term sustainability of fisheries and fish populations.
Protect, restore and sustain the diversity of the nearshore fish community, with an emphasis on self-sustaining native fishes such as Walleye, Yellow Perch, Lake Sturgeon, Smallmouth Bass, Largemouth Bass, sunfish, Northern Pike, Muskellunge, Round Whitefish and American Eel.
The Lake Ontario Committee's goal for a diverse nearshore fish community was largely met during the reporting period. Status/trend indicators were met for Yellow Perch, Walleye, and Smallmouth Bass, and these species continue to provide excellent angling opportunities in the nearshore zone. However, status/trend indicators were not met for Lake Sturgeon and American Eel restoration. Lake Sturgeon populations showed no trend during the reporting period and American Eel numbers remain far below target.
2.0 Offshore Pelagic Zone Goal
Maintain the offshore pelagic fish community, that is characterized by a diversity of trout and salmon species including Chinook Salmon, Coho Salmon, Rainbow Trout, Brown Trout, and Atlantic Salmon, in balance with prey fish populations and lower trophic levels.
The offshore zone in Lake Ontario continued to provide outstanding salmon and trout fisheries during the reporting period. Indicators for Chinook Salmon, Coho Salmon, and Brown Trout were met. Indicators for Rainbow Trout were mixed with the population indicators being met but the fishing quality indicator declining since the last reporting period. The offshore preyfish population indicator was met but the Alewife population also showed a declining trend. Indicators for Atlantic salmon restoration remained low during the reporting period.
3.0 Deep Pelagic And Offshore Benthic Zone Goal
Protect and restore the diversity of the offshore benthic fish community composed of a mix of self-sustaining native species including Lake Trout, Burbot, Lake Whitefish, deepwater ciscoes, Slimy Sculpin, and Deepwater Sculpin.
The Lake Ontario Committee's offshore benthic zone goal had mixed results during the reporting period. Indicators for the adult Lake Trout population were met but natural reproduction remains low and the long-term goal of a self-sustaining Lake Trout population has not been achieved. The indicator for Lake Whitefish populations in eastern Lake Ontario was also not met. However, benthic prey fish diversity and abundance both increased, and the first stocked Bloater were detected during the reporting period.