By Gregory Zimmerman, Lake Superior State University
Since 1977, Lake Superior State University’s Aquatic Research Lab in Sault Ste. Marie, Michigan, has been a center for research and outreach around the ecology of the St. Marys River and other aquatic habitats, as well as a focal point for student training in fisheries. The lab is probably best known for its Atlantic salmon hatchery program, in which it raises Atlantics for release into the river and Lake Huron system. Thanks to the lab, the experience of fishing for Atlantics in the St. Marys Rapids is cherished by locals and by visitors from around world.
The hatchery operations are impressive. Lake Superior State University (LSSU) is one of only a few universities that offer students direct work experiences in a hatchery that releases fish into public waters – but the lab does much more. Research projects in the river and Great Lakes, inland lakes, streams and wetlands advance science and provide information for improving the management of our resources.
Outreach activities inform residents and visitors about the importance of conserving our natural heritage. One example of outreach is the lab’s popular online “fish cam.” The lab is also a model of collaboration between the university, resource management agencies such as the Michigan Department of Natural Resources and Environment Canada, Cloverland Electric and other local organizations. Recent lab activities include a partnership in the Little Rapids Restoration project, the Great Lakes Coastal Wetlands Monitoring Program, sturgeon research, and more.
Now the lab is slated to take a big step in expanding its work. The facility will move from the current, rather cramped, space in the east end of the Cloverland Electric Hydro Plant to much larger space in the former Edison Sault office space on the west side of the plant. The lab will have about three times the space it currently has and be renamed the Center for Freshwater Research and Education (CFRE). The move has been in the works for several years, ever since Edison Sault donated the previous office building to the university. Plans include much-expanded research space for fish culture and fish health, space dedicated to public outreach, a K-12 discovery room, office space for researchers, and an outdoor educational park.
Two major sources of financial backing are moving the plans into reality. Last July, Michigan Gov. Rick Snyder signed an appropriations bill adding CFRE to the state’s capital outlay plan. The state would provide 75 percent of the funding with the university responsible for covering the rest of the costs. Then, this past December, Dick and Theresa Barch donated $500,000 to lead the way in helping the university raise its share of the estimated total of $11.8 million needed to build the Center.
For more information about the lab, visit www.lssu.edu/arl. For information about contributing to CFRE, contact LSSU Foundation Director Tom Coates at (906) 635-6670 or firstname.lastname@example.org.
Gregory Zimmerman is a professor of biology at Lake Superior State University. His research interests include control of invasive plant species in wetlands.
Editor’s Note: You can comment on issues raised in this article as part of the IJC’s public comment period on the Progress Report of the Parties and Triennial Assessment of Progress. Go to ParticipateIJC.org.
The makeup of Great Lakes fisheries could change in coming decades due to invasive species and the effects of the Great Lakes Water Quality Agreement, as popular stocked Pacific salmon species are numerically surpassed by native fish like walleye and lake trout.
“Although the fisheries have been good over the past two or three decades for salmon and trout in particular, we’re seeing the effects of a variety of invasive species coupled with nutrient reductions … on preyfish populations,” said Dr. John Dettmers, Fishery Management Program director with the Great Lakes Fisheries Commission. While on the whole fishing in the Great Lakes is good right now, Dettmers said there are warning signs that the more popular fisheries in the lakes over the past few decades may be nearing the “end of their life” as the food webs in the lakes come into a new equilibrium.
Lake Huron has been a bellwether for these trends. Pacific salmon species like Chinook or coho are stocked in the Great Lakes to prey on alewives, an invasive species that caused major ecological havoc in the mid-20th century prior to the salmon stocking. The alewives would overpopulate and cause mass die-offs, fouling beaches, until the salmon were introduced in the 1960s. Around 2003-2004, the alewife population crashed in Lake Huron, bringing down the salmon populations with it. Alewives have not made a comeback in the lake since then, and fishery management officials dramatically reduced their stocking of Pacific salmon into the lake.
Dettmers said managers in Lake Ontario and Lake Michigan also have reduced their salmon stocking targets for 2017 in an attempt to prevent a crash like the one in Lake Huron. Pacific salmon are a popular recreational fishing target, but they are by no means the only ones.
Native species fisheries on the rebound
Native fish species like walleye, lake trout and yellow perch may be looking at a recreational comeback in the coming decades, Dettmers said. In Lake Huron, those species have bounced back, and both walleye and yellow perch populations have been stable in Lake Erie. Lake trout, historically stocked within the basin after sea lamprey devastated their numbers in the first half of the 20th century, are reproducing naturally at measurable levels in several lakes, and managers are beginning to cut back on stocking.
According to Jay Wesley, Lake Michigan basin coordinator with the Michigan Department of Natural Resources, invasive zebra and quagga mussels have been an ongoing problem in recent decades. By eating phytoplankton and other bases of the food web, mussels will filter-feed nutrients out of the water column and sequester them near the shore and at the bottom of the lake, away from where preyfish traditionally find their meals. Coupled with the phosphorus fertilizer runoff reductions taking place under the Great Lakes Water Quality Agreement, Wesley said Lake Michigan is facing an “historic low of biomass of prey in the lake.” Alewives, smelt and bloater chub – fish that prefer to stay in the water column – are all on the decline, while other species like the lake herring, walleye or lake sturgeon – which prefer to hang out near the lake floor – are taking advantage of this nutrient move.
Matt Preisser, Lake Michigan coordinator with the Michigan Department of Environmental Quality’s Office of the Great Lakes, said round gobies, another invasive species in the lakes, also play a role in that nutrient shift. The bottom-dwelling gobies eat mussels and their populations have surged in recent years. Many researchers believe gobies are now a major prey fish in all of the lakes except Superior. Predator fish with more diversified diets and broader foraging behavior, such as lake trout, are benefitting from this improved prey source. Meanwhile, fish like Chinook salmon that don’t like going to the bottom to feed are worse off.
With more than 180 non-native species in the Great Lakes basin, Wesley said that managers are aware that as long as the Great Lakes are connected to global commerce, the risk of new species entering and disrupting the food web will remain. However, steps taken by Canada and the US to close off invasive pathways have led to only one confirmed new invasive species in the lakes since 2006. Dettmers added that fishery managers are still mindful that Asian carp species, especially bighead carp and silver carp, could migrate from the Mississippi River into the Great Lakes, upsetting those efforts to find a new equilibrium for the food web.
Contaminants and climate change harm fisheries and communities, too
There are other challenges facing fisheries aside from invasive species. Legacy contaminants like polychlorinated biphenyls (PCBs), mercury and dioxins can still be found in fish from the Great Lakes, though Wesley said trends indicate those materials are still declining. Primarily trout and salmon are the targets of fish consumption advisories, with members of high-risk populations like children and women of childbearing age being advised to not consume any affected fish in their area. The rest of the populace is generally asked to limit consumption and avoid fattier portions where these substances can collect. Canada and the United States have named PCBs and mercury as Chemicals of Mutual Concern in the Great Lakes basin.
Lake Superior is unique when it comes to fisheries management compared to the other lakes, Preisser said, as its fishery is “much more natural” and in better shape than the other four lakes. This is partially due to Lake Superior seeing less shipping traffic over the decades, and partially due to the comparatively limited development around it compared to the other lakes. It also means that managers are focused on preventing invasive species from getting a strong foothold in the lake and guarding against contaminants, while other lakes are primarily being restored.
And while climate change may not be having any noticeable impact on Great Lakes fisheries yet, Wesley said warming lake conditions would likely impact the tributaries some species spawn in first, as well as shallow spots like Green Bay. Some tribal governments around Lake Superior are shifting their fisheries from cold-water species to cool-water species due to warming temperatures in area waterways.
You can comment on the issues raised in this article as part of the IJC’s public comment period on the Progress Report of the Parties (PROP) and Triennial Assessment of Progress report (TAP). Go to ParticipateIJC.org.
Kevin Bunch is a writer-communications specialist at the IJC’s US Section office in Washington, D.C.
By Yu-Chun Kao
Department of Fisheries and Wildlife, Michigan State University
East Lansing, Michigan
In a paper recently published in the journal Ecosystems, my co-authors and I showed that the current prey base in Lake Huron can no longer support the same level of Chinook salmon that prevailed in the 1980s. Consequently, we indicated that the good old days of Chinook salmon fisheries are gone and will never return.
Results from this study also implied that Chinook salmon fisheries in Lakes Michigan and Ontario will possibly follow the same fate, because several food web changes associated with the Chinook salmon collapse in Lake Huron have already occurred in these two lakes.
Maybe it is time to rethink whether fisheries management in the Great Lakes should be focused on stocked exotic species that anglers desire, like Chinook salmon, or native species such as lake trout and walleye that are better adapted to changing ecosystems.
Chinook salmon and other fish in the salmon family were introduced to the Great Lakes 50 years ago to create recreational fisheries. The intent was to turn alewives from a nuisance fish to a food source for salmon. Alewives reached a nuisance level of abundance around 1960 and drew public attention after their decaying bodies fouled beaches after several massive die-off events.
Introduced salmon soon adapted to feed on alewives and successfully created multi-billion dollar fisheries.
Because salmon populations are artificially maintained or supplemented by hatchery stocking, the potential for predator–prey imbalance has been a concern for researchers since the early 1980s. Such an imbalance finally occurred in 2003 when the alewife population collapsed in Lake Huron.
However, the cause of this collapse is complicated. Since the late 1980s, prey fishes such as alewives and rainbow smelt had been experiencing increased predation pressure and a food shortage. Consumptive demands by salmon species first increased due to rises in stocking in the 1980s and then jumped sharply with natural reproduction of Chinook salmon in the 1990s. On the other hand, the production of algae at the base of lake food webs decreased because of feeding by invasive quagga mussels and reduction in nutrients after abatement programs initiated in the 1970s.
The year 2003 is unique in the ecological history of Lake Huron. It is the year when quagga mussels were first found, in significant amounts, in the deep part of the lake. It is also the year when there was a historical low of the nutrient inputs from agricultural and municipal sources. Since then, quagga mussels have been expanding while nutrient inputs have stayed at similar low levels.
While Chinook salmon fisheries collapsed in Lake Huron following the collapse of alewife population, estimates for sport angler harvests of Chinook salmon were close to a historical high in Lakes Michigan and Ontario during 2005–2008, despite increases in consumptive demand by salmon, expansion of quagga mussels, and a reduction in nutrients.
Nevertheless, according to our study, there is a clear warning signal for Chinook salmon fisheries in Lakes Michigan and Ontario. Chinook salmon have feed almost 100 percent on alewives in recent years.
Before the 21st century, Chinook salmon feed on both alewives and rainbow smelt. Rainbow smelt have continuously decreased since the 1990s because they are more vulnerable than alewives to food shortage caused by nutrient reduction and quagga mussel expansion. If the condition of Lake Huron after 2003 occurs in Lakes Michigan and Ontario, alewife populations in these two lakes will likely collapse, as well as Chinook salmon fisheries.
With ongoing changes in the Great Lakes, it will be more and more costly to maintain Chinook salmon fisheries. We have observed decreases in the alewife population and Chinook salmon harvests in Lake Michigan since 2010 despite the same, if not higher, level of managing efforts. On the other hand, harvests on native species like lake trout and walleye, which are better adapted to a food web without alewives, increased drastically in Lake Huron in recent years.
Now is the time, in my opinion, to rethink our fisheries management strategies for the Great Lakes.