New Consent Decree Jeopardizes Sustainability of Great Lakes Fishery Resources and the Fishers that Depend on Them

Introduction

The recently released draft Consent Decree between the State of Michigan, the United States, and four of the five tribes with fishing rights under the Treaty of 1836 represents a huge step backward in the protection and stewardship of Michigan’s fragile Great Lakes fisheries.

The State of Michigan, in negotiating this proposed Decree, abandoned the initiative of the 2000 Consent Decree to replace destructive, lethal gillnets commonly fished by the tribes with more selective and far less lethal trapnets.  In so doing, the proposed Decree opens to gillnetting vast reaches of Lake Superior that were, until now, trapnetting and recreational fishing zones.  Gillnetting “opportunities” have also been expanded in lakes Michigan and Huron.  In Lake Huron, the proposed Decree even opens a lake trout spawning refuge to gillnetting 10 months of the year and reduces its protective area by more than half.  This refuge, which until now was closed to gillnets and the harvest of lake trout, was given refuge status by the Canadian and US biologists coordinating their activities on Lake Huron under the aegis of the Great Lakes Fishery Commission.  Another refuge, the Northern Lake Michigan Refuge, is surrounded by waters suffering from effects of overfishing and which will now experience even more nets.  Lake trout were exterminated from lakes Huron and Michigan by overfishing and sea lamprey depredation.  They are still dependent on stocking in Lake Michigan and are staging a fragile recovery in Lake Huron; lake trout cannot sustain such increases in fishing pressure.  Zones for recreational and trapnet fishing designated by the previous consent decree had afforded lake trout protection from the impacts of gillnets and, thus, were centers for lake trout recovery.  These zones are vastly diminished, and gillnets will now be allowed in many of these areas.

This unleashing of fishing pressure is seriously at odds with the biological capacity of lakes Huron and Michigan.  These two lakes are suffering from the devastating effects of invasive zebra and quagga mussels and continue to struggle with the toll taken by the invasive sea lamprey.  Yet, the parties negotiating the proposed consent decree have done just the opposite of what is needed to protect the resource, significantly increasing fishing “opportunities” in all three lakes.  Whitefish in most areas of northern lakes Huron and Michigan have already collapsed to near economic extinction. If lake trout also collapse, most types of fishing activities will prove unsustainable.  Our shared heritage of subsistence, commercial and recreational fishing will be threatened, along with the economic and cultural well-being of families and businesses that have engaged in fishing for generations.

In summary, the proposed agreement ignores the reduced and fragile state of the resource and instead focuses on “new fishing opportunities” that can only accelerate the rate of the fish community’s decline.  The State’s failure to propose measures that would protect the resource represents a dereliction of its Great Lakes public trust responsibility.

The biological setting

The lakes tell us, in no uncertain terms, that fishing needs be carefully and conservatively managed to maintain balance between harvest and the new reality of shrinking fishing resources imposed in recent decades by a wave of invasive species.

The foodweb was irrevocably altered when two species of dreissenid mussels (zebra and quagga) invaded the Great Lakes via ballast water of salt-water-going cargo ships, which in turn had gained access to the Great Lakes by the St. Lawrence Seaway around Niagara Falls. During the 1990s, both species of mussels colonized all of the Great Lakes, but with only limited success in Lake Superior.  (Superior water is too “soft,” lacking sufficient calcium for the mussels to build shells, and too cold for zebra mussels.)  The mussels were soon followed the round goby, a cigar-sized, bottom-dwelling fish.  All three species are of Caspian origin.

The first documented casualty of the mussel invasion was the shrimp-like bottom dwelling Diporeia, which until about 2000, had been the dietary staple of lake whitefish (Nalepa et al., 2009; Nalepa et al., 2010). Today, Diporeia are nearly absent from lakes Huron and Michigan.  Although the exact cause of the Diporeia collapse remains unclear (Nalepa et al., 2005), both Diporeia and dreissenid mussels are filter feeders; that is, they feed on tiny particles, mostly suspended algae and detritus.  The filtering efficiency of enormous numbers of mussels may have worked to the detriment of Diporeia. Zooplankton, very small planktonic animals that feed on phytoplankton (the suspended algae) declined almost simultaneously with the collapse of Diporeia, evidently also a victim of mussel filtering (Holland, 1993; Kerfoot et al., 2010; Vanderploeg et al., 2010; Bacaniov et al. 2014).  Zooplankton are essential for survival of fry of certain species that hatch at very small sizes, and thus have small mouth openings, whitefish and walleye for example (Freeburg et al., 1990; Pothoven et al., 2014; Zorn and Kramer, 2022). As a result of “dreissenid reengineering” of nutrient pathways, nutrients in the nearshore zone tend to be sequestered in the form of periphytic (attached to lake bottom) filamentous algae and benthic invertebrate biomass (Hecky et al., 2004; Davies and Hecky, 2005; Malkin et al., 2010) which are not available to larval fish with small mouth gapes (Nalepa and Pothoven,2006; Higgens et al., 2008; Vanderploeg et al., 2010).  Lake whitefish reproduction in most of the northern portions of the two lakes reached critically low levels and by 2015 the lack of reproduction was evidenced by sharply declining catches (Ebener et al., 2022; Lennart, 2022; Modeling Subcommittee, Technical Fisheries Committee, 2017; see appended Figures 1 and 2).  The planktivorous mid-water alewife, upon which Chinook salmon depend for food, almost disappeared from Lake Huron (Riley et al., 2008) by 2005 and declined sharply in Lake Michigan (Bunnel et al. 2019); thus, the decline in zooplankton has far-reaching implications to the fish community.

Two foundational assumptions at the time of execution of the 2000 Consent Decree were that: a) robust Chinook salmon populations would be the mainstay of recreational fishing in both lakes Huron and Michigan; and b) a vibrant commercial fishery for lake whitefish, which had reached record-high harvest levels at the time of signing, would sustain the commercial and tribal subsistence fisheries for the foreseeable future.

The signers of the 2000 Consent Decree could not have imagined how swiftly and thoroughly their vision for the future would be reversed. By 2006, Lake Huron’s Chinook salmon were all but gone and Lake Michigan’s salmon were in decline.  Presently, whitefish catches are so low in some units that commercial fishers are seeking other species to sustain their businesses.

Such a steep decline in the resource represents a crisis for not only the resource but the fishers that depend upon it.  As opportunity to harvest whitefish declined, fishers have been shifting their targets to lake trout, but lake trout in lakes Michigan and Huron are not yet recovered from their local extinctions caused by a combination of sea lamprey depredation and overfishing (Eshenroder et al., 1992; Eshenroder et al., 1995; Johnson et al. 2004). Efforts to restore lake trout in the Great Lakes constitute one of North America’s largest-scaled keystone predator recovery projects (Johnson et al. 2015).  In the late 1950s, the Great Lakes Fishery Commission implemented a sea lamprey control program for the Great Lakes (Brant 2019).  Restocking of lake trout in Lake Huron began in the 1970s (Eshenroder et al., 1995; Whelan and Johnson, 2004; Johnson et al., 2015). It is important to recognize that avoiding any overfishing during recovery is essential to rehabilitation of this species. Similarly, walleye and yellow perch fisheries, particularly in Big and Little Bays de Noc, have suffered declines since 2000 and cannot sustain significant targeting by commercial fishing.

Healthy fish populations are the foundation of sustainable fishing, whether commercial or recreational; in other words, sustainable fishing opportunities can only be had with stable fish populations. To assure sustainability, the parties must recognize the dramatic reductions in the fish populations of lakes Michigan and Huron and squarely address the diminished state of the fishery by balancing harvest with today’s reduced capacity of the fish community.

The parties, therefore, must recognize the decreased availability of the leading target species for recreational (salmon) and commercial (whitefish) fishing since 2000. The appropriate biological response, in light of these changes, is to take a conservative approach in any new decree, one that protects the diminished whitefish stocks from overharvest while taking precautionary measures to protect lake trout and walleye as the focus of fishing shifts to these recovering native species. Recognition of these biological realities should have been the basis of negotiations for a renewed consent decree.

Proposed decree ignores reality of a diminished resource

Contrary to logic and the direction supported by biology, the parties have barely considered the changed trophic state of the lower two lakes and have, instead, been seeking “increased opportunities” to harvest whitefish, lake trout, walleye, and yellow perch.  The 2000 Consent Decree, in an effort to reduce mortality of nontarget species such as lake trout, directed $14 million to converting nonselective, lethal gillnets to more selective trapnet fisheries.  This conversion project has been abandoned in the proposed decree.  In a huge step backward, expansive new gillnetting opportunities that will increase fishing pressure have been proposed.

Recreational and trapnet fishing cannot compete with gillnet fishing conducted in the same spatial area.  As catch rates decline, gillnetters can maintain their harvest levels by simply setting more gillnet, whereas recreational and trapnet fisheries are less efficient than gillnets and are limited in how much effort they can deploy. “Zone Management”, which in the 1985 and 2000 Consent Decrees had protected recreational zones, trapnet fishing, and lake trout refuges from gillnetting, has been much diminished in the proposed decree. Recreational zones would be greatly reduced, and one refuge would be reduced to less than half its size and opened to gillnetting. Gillnet fishing proposed for the present recreational zone of Bays de Noc will further shrink the walleye and yellow perch populations there and jeopardizes the most important recreational fishing area of Michigan’s Upper Peninsula.  Most recreational and trap net zones in Lake Superior, designated by the 2000 Decree, will disappear.

Lake trout spawning refuges have been designated in northern lakes Michigan and Huron by inter-jurisdictional actions of the Great Lakes Fishery Commission Lake Committees. These refuges are designed to help protect recovering stocks from overfishing by prohibiting lake trout harvesting in the vicinity of historically important spawning areas.  A combination of the Drummond Island Refuge designation, the 2000 Consent Decree gillnet-to-trapnet conversion project, millions of dollars in lake trout stocking, and more millions of dollars in heightened sea-lamprey control, particularly in the St. Marys River, have contributed to rehabilitation of spawning lake trout in northern Lake Huron (Johnson et al., 2015). Spawning in northern Lake Huron appears to be supporting lake trout throughout the lake (He et al., 2020a). Since the collapse of alewives, lake trout stocking no longer is deemed economically viable (Lake Huron Committee Minutes 2012-2016). Thus, the proposal to open the Drummond Island Refuge to gillnetting is a unilateral action, unsanctioned by other Great Lakes Fishery Commission member agencies, that is likely to undermine progress to date in lake trout rehabilitation in Lake Huron.  It is unlikely the agencies can “stock their way out” of a second collapse of lake trout in Lake Huron as long as stocking continues to be ineffective.  In addition, Lake Michigan’s northern refuge will be surrounded by heightened gillnetting, almost assuring that mortality rates will exceed those necessary for restoration of lake trout.  The spawning refuge will, consequently, be almost devoid of lake trout old enough to spawn and the commercial fishery will continue to be supported by “put-grow-take” stocking and millions of tax dollars annually in fish hatchery costs.

Gillnetting compromises other Great Lakes fish populations, including lake sturgeon. Lake sturgeon number less than 1% of historical levels (Ed Baker:  https://www.michiganradio.org/environment-science/2020-08-11/dead-sturgeon-found-on-lake-michigan-beaches), are State-listed as “threatened” in Michigan, and a federal court has ordered the U.S. Fish and Wildlife Service to make a determination by 2024 whether imperiled populations of lake sturgeon will be protected under the Endangered Species Act. Restoration stocking of lake sturgeon began in Bays de Noc in 2006 and these stocked fish are relatively young, meaning they are of sizes to be vulnerable to the 4.5-inch gillnets most commonly fished for lake whitefish and lake trout.  Gillnets are non-selective, and their catch is often dead or moribund when landed (Johnson et al. 2004).  Thus, it is important to protect sturgeon rehabilitation sites from commercial gillnetting.

A more detailed review of the status of lake trout, walleye, and yellow perch is appended.

The proposed measures, if implemented in a new Consent Decree, will not only further destabilize fish populations and compromise sustainability of commercial fisheries, but they will also undermine recreational fishing and, therefore, represent a de facto allocation of almost all harvest in 1836 Treaty waters to tribal fishers.  Because lake trout and whitefish are slow growing and long-lived, a collapse of these species would take at least 10 years for even partial recovery to be realized.  A decade of lost fishing opportunity would mean economic extinction of fishing industries and livelihoods.

Engaging resource users as advocates for stewardship and sustainability

 The proposed agreement should foster an informed community of resource users:  Recreational and commercial fishers are often the most vocal and effective advocates for resource stewardship.  It was commercial fishers that most effectively advocated for sea lamprey control during the 1940s and 1950s (Brant, 2019). The finding of chlorinated hydrocarbon contamination of salmon during the 1970s marshalled a successful advocacy, led by recreational fishers, for banning of DDT and PCBs (Dempsey 2001). Informed fishers can foster support for sustainable management of fishery resources; therefore, a wise beginning to the negotiation of a new decree would have been outreach to the fishing communities with the objective of sharing with the fishers the constraints imposed upon fishing opportunity by invasive-species-triggered foodweb changes (largely negative on available fishing stocks). But the negotiations have been conducted in secret, under a “nondisclosure agreement” among the parties, and the fishers and other potential resource stewardship advocates were, until the recent public release of the proposed decree, not aware of any provisions of the agreement.

A shared understanding of resource conditions would also have laid a foundation of common understanding regarding causes of declining whitefish stocks and set the stage for discussion of needed research into corrective measures, such as whether restocking whitefish might restore some of the lost whitefish production. A shared understanding of the cause of recent declines in whitefish stocks and the tenuous status of lake trout in lakes Huron and Michigan would also have helped to establish realistic expectations for future fishing opportunities.  Only with a shared understanding of the depleted and fragile state of fish populations will regulation of the resource be met with widespread acceptance by its users.

Resource management strategies and harvest regulation

 Given the disastrous collapse of whitefish stocks in most waters of Lake Michigan and northern Lake Huron, the resource agencies must take a precautionary approach to future harvest management. The management framework set forth in the proposed decree must be based on this cautionary approach.

The parties (agencies and fishers) need to recognize that there are few, if any, opportunities for increasing harvest of either whitefish or lake trout in lakes Huron and Michigan.  Because both lake trout and whitefish now feed on the invasive round goby, and round gobies prefer rocky substrates, both target species will be concentrated on a finite number of exposed rock substrates.  The gillnet fishery is now likely to focus on such substrates; this will increase the catch of lake trout in gillnets targeting whitefish.  In many areas of these lakes, whitefish numbers are so low that gillnet fisheries are purposefully targeting lake trout, which are now more concentrated – and vulnerable – on rock-substrate feeding grounds. Thus, considering the tenuous status of lake trout recovery in both lakes Huron and Michigan and the recovery efforts for the threatened lake sturgeon, it would be prudent for the parties to continue with the limitation of gillnet effort initiated with the 2000 Decree.

Mortality of lake trout is above target levels in MM-1,2,3 (Northern Lake Michigan) and MM-4 (Traverse Bay).  While below-target levels now prevail in other Huron and Michigan units, any rise in lake trout bycatch in gillnets and any increase in gillnet targeting of lake trout would threaten the status of those stocks as well.

A cautionary approach that should protect these recovering stocks of lake trout would include:

1. Continuing the effort initiated by the 2000 Consent Decree to convert the nonselective, more lethal gillnet to trapnet effort.  This would have the added advantage of protecting lake sturgeon and other non-target species.
2. Prescribing lake trout total mortality rates that are below 40% for all lake trout management units and whitefish total mortality rates below about 45%.  Mortality targets were set in the 2000 Decree but have not been defined in the draft agreement, leaving this critical decision unresolved.
3. Recognizing that performance for the 13 working whitefish models is rated as “high” for only one of them, with the remaining rated as “medium” or “low” performing. With changing growth, recruitment, longevity, diets, distribution, and gear selectivity, models need to be continually updated and, even if they are, they lag behind real-time events in the fisheries.  Estimation of recruitment is especially inexact.  Given these uncertainties, a conservative approach to harvest estimation would be appropriate.  Presently, harvest is estimated based upon maximum sustainable mortality rates, which leaves no room for error.  Under such “maximum sustainable yield” approaches any overestimations of allowable harvest can compromise sustainability of the resource.  Allowing a “buffer” to shield the resource from harvest estimation error should be routine given the instability of the Huron and Michigan fisheries.
4. Recognizing that the commercial fishers are shifting from the diminishing whitefish, and recreational fishers from salmon, to lake trout fishing and, accordingly, take precautionary measures.  Such measures would include reviewing lake trout commercial harvest and recreational bag limits annually, as has been almost routine since the 2000 Decree; maintaining the trapnet and recreational fishing zones from the 2000 Decree as gillnet-free zones, reducing the number of zones where gillnets may be fished, and limiting entry of new gillnet effort by management unit.
5. Using zone management to protect especially valuable habitats or vulnerable aggregations of fish and to protect opportunities for recreational and trapnet fishers to realize their allocation of the resource.
6. Continuing to protect lake trout refuges from lake trout fishing. Refuges are one type of zone management that protect locations considered by the agencies to be the most productive spawning habitats.  These refuges are important to the lakes-wide management and recovery of lake trout.
7. Protecting large, vulnerable aggregates of lake trout during spawning season.  The spawning closure defined by the draft Decree is November 7 through November 29.  Most lake trout spawn in lakes Michigan and Huron beginning in mid-October and continuing until about November 20. Thus, lake trout are presently not protected during the height of their spawning and are extremely vulnerable to harvest during late October and early November.

 

Figure 1. Commercial harvest of lake whitefish from northern units (1836 Treaty Waters) of Lake Huron, from Lenart (2022).

Figure 2.  Commercial harvest of lake whitefish from northern whitefish management units of Lake Michigan, from Lenart (2022).

 Appendix I, Status of fisheries

Lake trout of Lake Huron

Beginning in 1984, reproduction was documented in Thunder Bay, western Lake Huron; however, after 1990 reproduction appeared to be in decline (Johnson and VanAmberg 1995).  Persistent sea lamprey depredation and localized overfishing contributed to delays in restoring spawning populations of lake trout.

An investment of approximately $5,000,000 (in addition to the usual approximately $15-$20 million annual cost of Great Lakes lamprey control) to treat the St. Marys River lamprey population (northern Lake Huron’s chief source of sea lampreys) brought sea lampreys to targeted levels.  A $14,000,000 investment in conversion of about half of tribal gillnets to trapnets appeared to resolve the overfishing issues in northern Lake Huron during the early 2000s.

Prior to the 2000 Consent Decree, two lake trout spawning refuges, closed to lake trout harvest and gillnet fishing, were designated in Michigan waters.  The Drummond Island Refuge in northern Lake Huron is in 1836 Treaty Waters and was accordingly designated as a refuge in the 2000 Consent Decree, with lake trout harvest and gillnet fishing prohibited. These important measures allowed rebuilding of lake trout spawning-stock biomass to targeted levels in all Michigan management units of Lake Huron by 2002.

Lake Huron lake trout were almost entirely of hatchery-origin in 2000 (Johnson et al., 2004) but by 2013, lake trout reproduction was evident lake wide and wild lake trout numerically composed approximately half of the Main Basin lake trout population; more than half of lake trout younger than 7 years old were wild and prospects for rehabilitation appeared promising (Johnson et al., 2015).  In the northern units, mortality targets were being achieved, spawning-stock biomass remained robust, and recent recruits were dominated by wild fish (Johnson and He, 2017).

However, the Lake Huron Technical Committee has now determined that stocking success for lake trout has declined to the point that it is no longer an economically viable tool for supporting lake trout populations in Lake Huron (Lake Huron Technical Committee meeting minutes, 2012-2016) and lake trout recruitment has declined in recent years, especially so in the south (He et al., 2020a).  Reproduction in central and southern units of Lake Huron is insufficient to support populations there and northern Lake Huron appears to be contributing to what lake trout are to be found in the more southern units of Lake Huron (He et al., 2020a).

Lake trout that spawn on the Drumond Island Refuge migrate to adjacent management units, including Ontario waters, where commercial exploitation of lake trout is relatively high. Some migrate long distances, apparently to find favorable feeding conditions, returning to the refuge to spawn in subsequent years (Binder et al., 2017).  Thus, protection of sustainable spawning populations of lake trout in the north appears to be essential to the future of lake trout in the entirety of Lake Huron.  Were reproduction to fail, stocking appears unlikely to be useful in any future recovery efforts.

He et al. (2020b) concludes:

“Thus, aggressive control of sea lamprey-induced mortality and fishing mortality will continue to be crucial for maintaining and further expanding the biomass and production of adult lake trout. A serious concern is whether the fixed harvest control rule, i.e. annual mortality of 40–45%, will continue to be closely implemented [that is, whether mortality rates will continue to be managed below this level; note by J. E. Johnson] in the future. Relaxation of the harvest control will likely lead to a downward trend in adult biomass and production, unless recruitment increases to such a level as to fully compensate for the expected increase in fishing mortality. Our findings also imply that the annual mortality might need to be further reduced unless substantial increases in recruitment occur soon.”

Lake trout in Lake Michigan

Similar to Lake Huron, lake trout recovery in Lake Michigan from decimation by overfishing and sea lampreys was a slow process, and it was not until after massive investment in sea lamprey control and reductions in fishing mortality that measurable reproduction was regularly measured in Lake Michigan (Holey et al., 1995; Lavis et al., 2003, Kornis et al., 2019).  As in Lake Huron, spawning refuges for lake trout are protected from lake trout harvest and gillnet fishing. Unlike Lake Huron and more southerly units in Lake Michigan, spawning-age lake trout in the Northern Lake Michigan Refuge and MM-1,2,3 declined almost 10-fold after 2000 due to a combination of increased sea lamprey, fishing mortality (Kornis et al., 2019), and reduced stocking there (Madenjian and Decorcie 2010).

Following restoration of stocking levels and improved sea lamprey control, spawning-age lake trout biomass was restored to former levels (but still below targeted parameters for recovery) by 2019 (Madenjian et al., 2020). This decline and recovery illustrate the sensitivity of recovering lake trout populations to changes in recruitment and mortality. It should be noted that reproduction of lake trout in MM-123 remains very low and this unit’s lake trout is a “put-grow-take” commercial fishery almost entirely dependent on a massive stocking effort.

Lake trout mortality rates have regularly exceeded target levels in MM123.  In MM-4 (Grand Traverse Bay), lake trout mortality rates regularly exceeded target levels until 2019, a year that the recreational bag limit was reduced to 1 fish.  Unclipped, wild lake trout began to regularly contribute to recruitment in Traverse Bay beginning in 2014, although the incidence remains low (Modeling Subcommittee, Technical Fisheries Committee, 2020).

In MM-5 (Leland area), where most harvest since about 2005 is from recreational fishing, mortality rates declined to below target level almost immediately after the 2000 Consent Decree and wild fish are regularly contributing to recruitment. Declines in sea lamprey-induced mortality in this unit have also contributed to decline in total mortality and a rise in spawning-age lake trout biomass (Modeling Subcommittee, Technical Fisheries Committee, 2020). Mortality rates in MM-67 (the most southerly units of 1836 Treaty Waters) declined to below target levels beginning in 2004. Most harvest in this zone, under provisions of the expiring 2000 Decree, is recreational.  Reproduction has been most pronounced in this unit, rising to 34% by 2019.  Stocking, however, was reduced here in 2017 and unless reproduction is sufficient to replace the stocked fish, there will be a commensurate reduction in fish available for harvest in future years (Modeling Subcommittee, Technical Fisheries Committee, 2020).

Walleye in Lake Michigan

Little Bay de Noc and Big Bay de Noc (MM-1) together constitute the most important recreational fishery of the Upper Peninsula of Michigan.  The bays’ walleye and yellow perch populations are the primary target of anglers.

Since dreissenid colonization of the bays, however, recreational fishing effort has declined 57% (Zorn and Kramer, 2022).  Zooplankton densities were very low during 2014-2016 (Zorn et al. 2020). Overall, increases in water clarity and declines in zooplankton densities appear to have caused a significant decline and redistribution of walleye in the bays (Zorn and Kramer, 2022).  Walleye of the bays, especially larger females, now are seasonally leaving Little Bay de Noc, most likely in search of more favorable feeding areas (Whitinger et al., 2022).  These recent changes have probably contributed to the decline in angling use of the bays.  The bays’ walleye population has been supplemented by stocking, which has largely been conducted by the local angling group “Bay de Noc Great Lakes Sportfishermen.”

Walleye and yellow perch elsewhere

Walleye and yellow perch are scarce in Lake Superior, but isolated populations of both are found in Little Traverse Bay, Grand Traverse Bay, and Hammond Bay. None of these populations are large enough to sustain a commercial-scaled fishery. Yellow perch are a mainstay of the very important recreational fishery of the Les Cheneaux Islands of northern Lake Huron.

Lake Sturgeon

Lake sturgeon number less than 1% of historical levels (Ed Baker:  https://www.michiganradio.org/environment-science/2020-08-11/dead-sturgeon-found-on-lake-michigan-beaches), are State-listed as “threatened” in Michigan, and a federal court has ordered the U.S. Fish and Wildlife Service to make a determination by 2024 whether imperiled populations of lake sturgeon will be protected under the Endangered Species Act. Restoration stocking of lake sturgeon began in Bays de Noc in 2006 and these fish are relatively young, meaning they are of sizes to be vulnerable to the 4.5-inch gillnets most commonly fished for lake whitefish.  Gillnets are non-selective, and their catch is often dead or moribund when landed.  Thus, it is important to protect sturgeon rehabilitation sites from commercial gillnetting.

Lake Superior

Lake Superior’s lake trout population is nearly fully rehabilitated from its decimation by sea lampreys (He and Sitar, 2006).  Lake Superior was spared the impacts of dreissenid mussels and, thus, its foodweb remains essentially unchanged since approximately the 1940s.  Though its whitefish and lake trout populations are presently sustainable and healthy, declines in fish stocks in lakes Huron and Michigan could foreshadow a shift in commercial fishing effort from lakes Michigan and Huron to Lake Superior as commercial fishers seek to maintain sufficient catch rates.

Lake Superior’s recreational fishery has, in certain locations, been protected from a rise in commercial exploitation by the designation of recreational fishing zones. Whitefish unit WFS-08 (in Brimley area of Whitefish Bay) is an exception to the general health of Lake Superior’s fisheries.  Fishing effort is high enough there that lake trout are scarce and whitefish mortality rates have exceeded target levels of 60% annual mortality from 2016-2018.  Whitefish harvest reached record-high levels from 2016-2018 and there has been a nearly continuous decline in spawning-age whitefish since the mid-1990s. Commercial effort (amount of gear fished) rose sharply in WFS-08 beginning in 2013 (Modeling Subcommittee, Technical Fisheries Committee, 2020).  The rise in effort in WFS-08 could represent a beginning of a shift of commercial effort from the lower two lakes to Lake Superior. The status of this stock of whitefish can only be described as stressed and unstable.

Appendix II, Consequences of proposed decree

The proposed consent decree fails to address resource limitations and proposes actions that would increase fishing pressure.  Such actions at this time of resource crisis constitute the State of Michigan’s abdication of its Public Trust responsibilities to the Citizens of Michigan. They also constitute an abdication of the Tribes’ responsibility to preserve the fishery for future generations. These actions will do irreparable harm to Great Lakes public-trust resources and the people that depend upon their sustainability. Examples of harmful actions include:

1. Opening the Drummond Island Refuge to gillnet fishing and harvesting of lake trout until October 1.  Such a proposal would violate the State of Michigan’s obligations to the Great Lakes Fishery Commission’s Joint Strategic Plan for Management of Great Lakes Fisheries (http://www.glfc.org/pubs/misc/jsp97.pdf) to which the State is signatory. The Drummond Island Refuge was established by interagency consensus in 1985 as part of the rehabilitation effort for lake trout in Lake Huron. To our knowledge, no resource manager from the member international agencies of the Great Lakes Fishery Commission Lake Huron Committee and its technical committee has suggested that this refuge is no longer necessary. Hosting the best spawning habitat and some of the most important rock substrates, which are attractive to lake trout feeding on gobies, the refuge acts as a buffer from the potential overfishing of MH-1’s lake trout.  Lake trout begin concentrating near the spawning reefs as early as mid-September (Michigan DNR Alpena Fishery Research Station, unpublished data). Opening the refuge to gillnet fishing will increase the exploitation rate on a recovering lake trout population and jeopardize its future trajectory, which presently is showing a modest, and concerning, decline in biomass.
2. Excessive harvest is being permitted around Lake Michigan’s Northern Refuge.  MM-1,2,3 and portions of MM-5 are adjacent to or near the Lake Michigan Northern Refuge.  Mortality rates are too high in MM-1,2,3 for the development of spawning stocks. It must be said that the utility of a spawning refuge is seriously compromised when spawning-age fish are scarce.  Those grids surrounding the Northern Refuge should be targeted for especially guarded harvest management, with target mortality rates set at 40% or less and with enforcement and penalties commensurate with the importance of protecting these stocks. Enforcement and penalties are not defined in the proposed decree.
3. Opening of Bays de Noc to gillnet fishing.  Walleyes are perhaps the most vulnerable of Great Lakes fish to gillnets because of their teeth, spines and sharp opercula (gill covers) which readily entangle in the mesh. Walleye can be efficiently targeted with gillnets on rock substrates of the bays (Zorn and Kramer, 2022).  Commercial gillnet fisheries can rapidly deplete walleye stocks to the point that recreational fishing for them is no longer feasible.  Thus, increasing commercial exploitation of walleye in the bays would not only potentially destabilize the population but would compromise the recreational fishery’s ability to realize its allocation. Some of these walleyes are products of stocking by the Bay de Noc Great Lakes Sportfishermen Association.
4. Commercial fishing for perch and walleye in other waters. There are almost no yellow perch or walleye stocks in 1836 Treaty Waters that can sustain directed commercial fishing.  The lakes are too cold and unproductive to be capable of producing fisheries for these species of a commercial scale and this condition has been exacerbated by the dreissenid invasion.  Where walleyes are targeted, stocking is usually necessary to sustain populations, and numbers are so suppressed by commercial fishing as to prevent recreational fishers from engaging in those fisheries. Expanding commercial exploitation of perch and walleye will further erode the recreational fishery’s ability to realize a fair allocation of harvest.
5. Increased gillnetting “opportunities” in Grand Traverse Bay, Little Traverse Bay, and MM-5, 6, and 7 in Lake Michigan and increased gillnet opportunities in Hammond Bay, Lake Huron, would increase exploitation of the beleaguered whitefish and potentially compromise the promising recovery trajectory of lake trout in these areas. Lake trout mortality targets are being exceeded regularly in Grand Traverse Bay; thus, only a slight increase in exploitation could bring reproduction there to a halt.
6. In 2019, the recreational fishery accepted a lake trout daily bag limit reduction to just one fish per day in Grand Traverse Bay and two fish in northern Lake Huron.  The reduced bag limit in Grand Traverse Bay brought mortality down to target levels there that year. Increasing commercial fishing that targets lake trout in the wake of these angling penalties is totally inappropriate and will stymy the emergence of reproduction. Gillnets are more efficient than trapnets or angling and an increase in gillnetting could bring catch rates down to the point of economic extinction for the trapnet and recreational fisheries, depriving them of their allocations of harvest. A case in point is Rogers City, nearly adjacent to the proposed unlimited shallow-water (less than 50 ft) gillnetting opportunity during spring on 40-Mile Point.  Lake trout aggregate densely in these rocky shoal waters to prey on round gobies. Increased lake trout exploitation there will inevitably cause erosion of recreational catch rates and compromise the economic vitality of Rogers City and its marina development, which was partially predicated on the vibrant recreational fishery the area has enjoyed under the 2000 Decree.

An example of the consequences of a targeted and unlimited gillnet fishery is illustrated by 1978-79 DNR assessment data from Hammond Bay–Cheboygan areas of northern Lake Huron.  The DNR’s assessment fishing there measured an 83% drop in lake trout density between 1978 and 1979.  Survival rate was less than 2% for the 1973 cohorts of lake trout in 1979; these cohorts were at record high abundance levels in 1978 and the decline coincided with an intensive gillnet fishery that operated on those grounds in fall 1978 (Cruise report for the Michigan DNR Research Vessel Chinook, May 28-June 29, 1979.  Michigan Department of Natural Resources, Alpena Fishery Research Station, Unpublished Report). A single fall season of gillnetting nearly eliminated the lake trout population there.  Similarly, a wave of gillnet effort in Grand Traverse Bay in 1979 reduced the lake trout stock there by over 90% in a matter of months. These are examples of the “fishing up” of targeted stocks of fish: when a lucrative fishery is identified, the fish population is intensely targeted causing the stock to decline.  As the stock declines, gillnet fishers respond by setting ever more gillnet.  Effort spirals up until the targeted stock is almost fished out and no longer attractive as a fishery.  This fishing up can have disastrous effects in as little as a few months, as shown above.

1. Increasing exploitation rates of lake whitefish while their population levels in Lake Huron and Lake Michigan are extremely depressed puts at risk the future of commercial fishing on lakes Michigan and Huron, where whitefish are the mainstay of the fishery. Whitefish represent a species of special cultural heritage and economic importance.
2. Harvest policy and status of the stocks need to be reviewed at last annually and more frequently where populations are especially depressed, yet the proposed decree would review harvest policy only every 3 years and mortality targets every 6 years. Such infrequent reviews of harvest policy could have disastrous consequences. As we have seen during the early 2000s, much can happen to fish populations and fishing patterns in as few as one or two years. The proposed decree needs to set initially conservative target mortality rates for recovering and stressed stocks to reverse the declining trend in the status of fisheries of lakes Huron and Michigan. The proposed decree fails to set objective-based mortality targets and delegates setting of mortality rates to the Executive Council with input from the Technical Fisheries Committee, which leaves this critical need unresolved. It is essential that harvest limits be reviewed annually and that corrective adjustments be made to harvest plans on a timely basis, at least until lakes Huron and Michigan begin showing signs of stabilization and self-sustainability.
3. Eastern Lake Superior (MI-8) is realizing whitefish mortality rates that are higher than anywhere in Treaty of 1836 waters and the rates are increasing.  This should be looked at with alarm because a failure of these “home waters” for the Bay Mills and the Sault tribes would undermine an ancient fishery heritage.  We see no effort to direct attention to this issue. Instead, the proposed decree incentivizes an increase in gillnet effort.  The decline of whitefish in lakes Huron and Michigan will probably cause gillnet fishers to focus even more effort on Lake Superior, thus further declines in the status of whitefish in MI-8 seems likely.

Appendix III, Bibliography

Binder T.R., J. E. Marsden, S.C. Riley, J.E. Johnson, N.S. Johnson, J. He, M. Ebener, C.M. Holbrook, R.A. Bergstedt, C.R. Bronte, T.A. Hayden, C.C. Krueger. 2017. Movement patterns and spatial segregation of two populations of lake trout Salvelinus Namaycush in Lake Huron. Journal of Great Lakes Research 43:108–118. https://doi.org/10.1016/j.jglr.2017.03.023.

Brant, C.  2019. Great Lakes Sea Lamprey, the 70 Year War on a Biological Invader.  University of Michigan Press, Ann Arbor. 180 pp.

Bunnell, D. B., C. P. Madenjian, T. J. Desorcie, P. Armenio, and J. V. Adams. 2019. Status and Trends of Prey Fish Populations in Lake Michigan, 2018. Report to the Lake Michigan Committee.  U.S. Geological Survey, Great Lakes Science Center, Ann Arbor, Michigan.

Davies, J. M., and R. E. Hecky. 2005.  Initial measurements of benthic photosynthesis and respiration in Lake Erie.  J. Great Lakes Res. 31, 195-205.

Dempsey, D. 2001. Ruin and Recovery, Michigan’s Rise as a Conservation Leader. University of Michigan Press, Ann Arbor.  336 pp.

Ebener, M.P., Dunlop, E.S., and Muir, A.M. 2021. Declining recruitment of Lake Whitefish to fisheries in the Laurentian Great Lakes: management considerations and research priorities [online]. Available from  www.glfc.org/pubs/misc/2021-01.pdf.

Eshenroder, R. L., D. W. Coble, R. E. Bruesewitz, T. W. Fratt, and J. W. Scheirer.  1992.  Decline of lake trout in Lake Huron.  Transaction of the American Fisheries Society 121: 458-554.

Eshenroder, R. L., N. R. Payne, J. E. Johnson, C. Bowen II, M. P. Ebener.  1995.  Lake trout rehabilitation in Lake Huron.  Journal of Great Lakes Research 21 (Supplement 1):108-127.

Freeberg, M. H., Taylor, W. W., Brown R. W., 1990.  Effect of egg and larval survival on year-class strength of lake whitefish in Grand Traverse Bay, Lake Michigan.  Transactions of the American Fisheries Society. 119:92-100.

He, J. X. and S. P. Sitar. 2006. Growth and Maturity of Hatchery and Wild Lean Lake Trout during Population Recovery in Michigan Waters of Lake Superior. Transactions of the American Fisheries Society Volume 135: 915-923.

He, J. X., J. R. Bence, C. P. Madenjian, S. A. Pothoven, N. E. Dobiesz, D. F. Fielder, J. E. Johnson, M. P. Ebener, A. R. Cottrill, L. C. Mohr, and S. R. Koproski.  2015.  Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron.  Canadian Journal of Fisheries and Aquatic Sciences 72:7-23.

He, J. X., J. Jolley, C. Davis, D. Hondorp, and C. Olds. 2020a.  Managing Current Transition of the lake trout population in the Main Basin of Lake Huron. Lake Huron Technical Committee Task Group Report to the Lake Huron Committee.  Great Lakes Fishery Commission, Ann Arbor.

He, J. X., J. R Bence, C. P.  Madenjian, and R. M. Claramunt. 2020b. Dynamics of lake trout production in the main basin of Lake Huron.  ICES Journal of Marine Science,  doi:10.1093/icesjms/fsaa030.

Hecky, R. E., Smith, R. E. H., Barton, D. R., Guildford, S. J., Taylor, W. D., Charlton, M. N., Howell, T.  2004.  The nearshore phosphorus shunt: a consequence of ecosystem engineering by dreissenids in the Laurentian Great Lakes.  Canadian Journal of Fisheries and Aquatic Sciences.  61: 1285-1293.

Higgins, S. N., Malkin, S. Y., Howell, E. T., Guildford, S. J., Campbell, L., Hiriart-Baer, V., Hecky, R. E., 2008.  An ecological review of Cladophora Glomerata (Chlorophyta) in the Laurentian Great Lakes.  Journal of Phycology. 44, 839-854.

Holey, M. E., R. W. Rybicki, G. W. Eck, E. H. Brown Jr., J. E. Marsden, D. D. Lavis, M. L. Toneys, T. N. Trudeau, and R. M. Horrall. 1995. Progress toward Lake Trout restoration in Lake Michigan. Journal of Great Lakes Research 21(Supplement 1) :128–151.

Holland, R. E.  1993.  Changes in planktonic diatoms and water transparency in Hatchery Bay, Bass Island area, western Lake Erie since the establishment of the zebra mussel.  Journal of Great Lakes Research 19: 631-653.

Johnson, J. E., and J. P. Vanamberg.  1995.  Evidence of natural reproduction of lake trout in western Lake Huron. Journal of Great Lakes Research 21 (Supplement 1):253-259.

Johnson, J. E., M. P. Ebener, K. Gebhardt, and R. Bergstedt.  2004a. Comparison of Catch and Lake Trout Bycatch in Commercial Trap Nets and Gill Nets Targeting Lake Whitefish in Northern Lake Huron. Michigan Department of Natural Resources Fisheries Research Report 2071, 2004

Johnson, J. E., J. L. Jonas, and J. W. Peck. 2004. Management of commercial fisheries bycatch, with emphasis on lake trout fisheries of the Upper Great Lakes. Michigan Department of Natural Resources Fisheries Research Report 2070;

Johnson J. E., M. P. Ebener, K. Gebhardt, and R. Bergstedt. 2004b. Comparison of catch and lake trout bycatch in commercial trap nets and gill nets targeting lake whitefish in northern Lake Huron. Michigan Department of Natural Resources Fisheries Research Report 2071;

Johnson, J. E., and G. P. Rakoczy. 2004. Investigations into recent declines in survival of brown trout stocked in Lake Charlevoix and Thunder Bay, Lake Huron. Michigan Department of Natural Resources, Fisheries Research Report 2075, Ann Arbor.

Johnson, J. E., S. P. Dewitt, and J. A. Clevenger. 2007. Causes of variable survival of stocked chinook salmon in Lake Huron. Michigan Department of Natural Resources, Fisheries Research Report 2086, Ann Arbor, Michigan.

Johnson, J. E., J. X. He, and D. G. Fielder.  2015. Rehabilitation Stocking of Walleyes and Lake Trout: Restoration of Reproducing Stocks in Michigan Waters of Lake Huron, North American Journal of Aquaculture, 77, 396-408.

Johnson, J. E., and J. X. He.  2017. Lake trout where you need them—restoring reproducing lake trout in Michigan waters of Lake Huron. Proceedings of the Wild Trout XII Symposium, West Yellowstone:157-171.

Kerfoot, W. C., F. Yousef, S. A. Green,  J. W Budd, D. J Schwab, and H. A Vanderploeg. 2010.  Approaching storm: Disappearing winter bloom in Lake Michigan.  Journal of Great Lakes Research 36 (Supplement 3): 5-19.

Kornis, M. S., C. R. Bronte, M. E. Holey, and ten others. 2019. Factors affecting post-release survival of coded-wire-tagged lake trout in Lake Michigan at Four Historical Spawning locations. North American Journal of Fisheries Management 39:868–895.

Lavis, D. S., M. P. Henson, D. A. Johnson, E. M. Koon, and D. J. Ollila. 2003. A case history of Sea Lamprey control in Lake Michigan: 1979 to 1999. Journal of Great Lakes Research 29 (Supplement 1):584–598.

Lenart, S. 2022. Status and management of lake whitefish in 1836 Treaty Waters of the Great Lakes.  Presentation to the Michigan Fish Producers Association.  Michigan Department of Natural Resources.

Madenjian, C. P., and T. J. Desorcie. 2010. Lake Trout population dynamics in the Northern Refuge of Lake Michigan: implications for future rehabilitation. North American Journal of Fisheries Management 30:629–641.

Madenjian, C. P, C. Bronte, K. Donner, J. Jonas, M. Kornis, S. Lenart, L. Schmit T. Traska. 2020. Lake Michigan Rehabilitation Strategy Review. A report to the Lake Michigan Committee.  Great Lakes Fishery Commission, Ann Arbor.

Modeling Subcommittee, Technical Fisheries Committee.  2020.  Status of lake trout and lake whitefish populations in the 1836 Treaty-ceded waters of lakes Superior, Huron, and Michigan, with recommended yield and effort levels for 2020. Technical Fisheries Committee Administrative report.

Nalepa, T. F., Fanslow, D. L., Messick, G.   2005.  Characteristics and potential causes of declining Diporeia spp. populations in southern Lake Michigan and Saginaw Bay, Lake Huron. Pages 157-188 in: Mohr, L.C., and Nalepa, T.F. (Editors). Proceedings of a workshop on the dynamics of lake whitefish (Coregonus clupeaformis) and the amphipod Diporeia spp. in the Great Lakes. Great Lakes Fisheries Commission Technical Rep. 66.

Nalepa, T. F., Pothoven, S. A., Fanslow, D. L., 2009.  Recent changes in benthic macroinvertebrate populations in Lake Huron and impact on the diet of lake whitefish (coregonus clupeaformis).  Aquatic Ecosystem Health & Management 12, 2-10.

Nalepa, T. F., Fanslow, D. L., Pothoven, S. A.  2010.  Recent changes in density, biomass, recruitment, size structure, and nutritional state of Dreissena populations in southern Lake Michigan.  Journal of Great Lakes Research 36 (Supplement 3), 5-19.

North, R. L., R. E. H. Smith, R. E. Hecky, D. C. Depew, L. F. Leon, M. N. Carlton, S. J. Guildford.  2012.  Distribution of seston and nutrient concentrations in the eastern basin of Lake Erie pre- and post-dreissenid mussel invasion.  International Association of Great Lakes Research 38:463-476.

Pothoven, S A., and T. F. Nalepa. 2006. Feeding ecology of lake whitefish in Lake Huron. Journal of Great Lakes Research 32:489-501.

Pothoven, S. A., T. O. Höök, and C. R. Roswell. 2014. Feeding ecology of age-0 lake whitefish in Saginaw Bay, Lake Huron Journal of Great Lakes Research Suppl. 40:148-155.

Riley, S. C., E. F. Roseman, S. J. Nichols, T. P. O’Brien, C. S. Kiley, and J. S. Schaeffer.  2008.  Deep water demersal fish community collapse in Lake Huron.  Transactions of the American Fisheries Society 137(6):1879-1890.

Sitar, S. P., and J. X. He.  2006. Growth and Maturity of Hatchery and Wild Lean Lake Trout during Population Recovery in Michigan Waters of Lake Superior. Transactions American Fisheries Society 135:915-923.

Vanderploeg, H. A., Liebig, J. R., Nalepa, T. F., Fahnenstiel, G. L., Pothoven, S. A.  2010.  Dreissena and the disappearance of the spring phytoplankton bloom in Lake Michigan.  Journal of Great Lakes Research 36 (Supplement 3), 50-59.

Whelan, G. E., J. E. Johnson.  2004.  Successes and failures of large scale ecosystem manipulation using hatchery production: the Upper Great Lakes experience. In: Propagated Fish in Resource Management.  American Fisheries Society Symposium 44:3-32.

Whitinger, J. A., T. G. Zorn, and B. S. Gerig. 2022. Changes in trophic ecology and movement of walleye following widespread establishment of dreisensid mussels. North American Journal of Fisheries Management 42:572-584.

Zorn, T. G. and D. R. Kramer.  2022. Changes in habitat conditions, fish populations, and the fishery in northern Green Bay, Lake Michigan, 1989-2019.