Great Lakes Food Webs Science: GLFC Lake Committees

“Time is but the stream I go a-fishing in.” – Henry David Thoreau

At the end of every March, the binational Great Lakes Fisheries Commission (GLFC) holds their public Lake Committee meetings for agencies to report out on the status of each lake. The GLFC was formed by a treaty signed in 1954 to regulate fishing and to fight the binational problem of Sea Lamprey. The location of the meetings move around between the US and Canada, and this past week, the meetings were held in Bay City, Michigan. The Joint Strategic Plan lake committees invite speakers to present science and management information to develop state of the lakes reports.  The meetings occur over 5 days, always starting with the upper Great Lakes, Michigan, Superior and then Huron and the lower lakes, Erie and Ontario. It is an important opportunity for scientists and managers to meet and discuss the health and status of the Great Lakes, but also to use some of their time for activities such as the euchre night and socials to renew some professional relationships.

Logos for GLFC, USFWS, USACE, NOAA, USGS and Canada DFO.

The Great Lakes fishery is one of the planet’s most valuable freshwater resources. The recreational and commercial fishery is worth more than $7 billion annually, supports 80,000 jobs, and is vital to Indigenous communities and their cultural heritage. Fishery management is accomplished collaboratively by non-federal governments: US states, the province of Ontario, and US tribes. As part of these responsibilities, these governments license, determine harvest levels, stock fish, and improve aquatic habitat. Federal agencies assist these governments and provide support for large binational programs such as Sea Lamprey Control.

a structure of the Great Lakes Fisheries organization showing Canadian and US programs and structure.

Federal (USGS, USFWS, DFO), the Province of Ontario (MNRF) and state (MN, WI, MI, IL, IN, OH, PE, NY) agencies, Tribes and First Nations, and university partners will report on various status indicators. Not surprisingly, the reporting out is generally focused around the status of fish populations and presentations are targeted to relevant fish communities for each lake. Many of the scientific presentations were also related to new technology, methods or tools relevant to management. Typically there are working groups that provide presentations often by fish taxonomic or habitat groupings: salmonids, prey-fishes, cold-water, warm-water and also reports on lower-trophic levels, stocking activities, aquatic invasive species monitoring, and populations of Sea Lamprey and control activities. These are given a status ranking of good, fair or poor.

graphics for good in green, fair in yellow, and poor in red.

Key fishes of interest for most of the lakes are a diverse grouping of salmonids: Chinook Salmon (Oncorhynchus tshawytscha), Coho Salmon (Oncorhynchus kisutch), Rainbow “Steelhead” Trout (Oncorhynchus mykiss), Brown Trout (Salmo trutta) and native Lake Trout (Salvelinus namaycush) and Atlantic Salmon (Salmo salar). Except for Lake Trout and Atlantic Salmon (in Ontario), all of the other species are introduced pacific salmonids that have been stocked since the late 1960s to control overly high populations of Alewife. Key prey-fishes that are assessed include Alewife (Alosa pseudoharengus), Bloater (Coregonus hoyi), Round Goby (Neogobius melanostomus), Rainbow Smelt (Osmerus mordax), and other species. Benthic fishes of importance are: Lake Whitefish (Coregonus clupeaformis), Round Whitefish (Prosopium cylindraceum), Lake Sturgeon (Acipenser fulvescens), Burbot (Lota lota) and suckers such as White Sucker (Catostomus commersonii). Inshore or warm-water fishes of interest are Yellow Perch (Perca flavescens), Walleye (Sander vitreus), Pike (Esox lucius), Muskellunge (Esox masquinongy), Smallmouth Bass (Micropterus dolomieu), and various other Centrarchid sunfishes such as Bluegills (Lepomis macrochirus).

Illustrations of important Great Lakes fishes. Lake Whitefish, Chinook Salmon, Alewife, Round Goby, Rainbow Smelt, Walleye, Lake Trout and Lake Sturgeon.

For Lake Michigan, there was quite a bit of discussion about the drop in lake productivity, Quagga Mussels and changes to forage for fishes. Like many lakes, there has been a particular concern about the severe reduction to Lake Whitefish populations. Because of the proximity to several prominent US labs on Lake Michigan, technology was a popular topic. Peter Esselman (USGS) gave a presentation on surveying the bottom of the lake for Round Gobies using an autonomous underwater vehicle “GobyBot”, Steve Ruberg (NOAA) presented on autonomous underwater gliders, and Tom Evans (Cornell) on the use of the autonomous Saildrone acoustic surveys of prey-fishes.

Lake Superior, having no invasion of Driessena Zebra or Quagga Mussels or Round Goby has more of a focus on Coregonine fishes, with four species of Ciscoes: Cisco (Coregonus artedi), Bloater (Coregonus hoyi), Kiyi (Coregonus kiyi) and Shortnose Cisco (Coregonus reighardi) and Lake Whitefish (Coregonus clupeaformis). Owen Gorman (USGS) gave a very interesting presentation on the confirmation of previously thought extirpated Shortnose Cisco, which was only possible through a collaboration of many agencies including DFO.

A large ballroom filled with people.

Lake Huron continued the discussion about the continued decline to productivity in the lake. This was also an opportunity for reporting out of findings from the 2022 Cooperative Science and Monitoring Initiative (CSMI) field-year on Huron including some lakewide cruises hosted by DFO. There are places of higher productivity including Saginaw Bay and North Channel of Georgian Bay, but overall Lake Huron is very low productivity and is the clearest (deepest Secchi depth measures) of all the Great Lakes now. Lake Huron went through a rapid change in state after 2003 when the Alewife crash led to the loss of Chinook Salmon in the lake and steady declines in Lake Whitefish. Taylor Brown (Cornell) gave an excellent talk on Coregonine recruitment for all of the Great Lakes, which was particularly relevant to this system. Lake Huron has several long-term commercial Lake Whitefish fishing operations and several members of those communities expressed concerns about having targets for Lake Trout when there was no market for them. These lake meetings are the chance for the public to provide feedback to the Commission.

The Common Session is the venue for discussions which relate to all the Great Lakes. Presentations were given on binational law enforcement, Science Transfer tools to inform management, eDNA methodology, and a new dashboard to report out on State of the Lake.

presenters talking at a podium on Lake Ontario and Lake Erie fish status.

Next were the lakes which our lab generally has the most involvement. The Lake Ontario session had talks on Coregonine, Atlantic Salmon and Lake Trout restoration, status of Salmonids, stocking decisions and presentations on lower foodweb and prey-fishes status. The 2023 field year was the CSMI for Lake Ontario so several of our monitoring and research activities were particularly relevant to this session, including our Mysis surveys, and it is an opportunity to follow up with some of our collaborators about the status of some of our projects.

a set of images of historical and modern commercial fishing in Lake Erie, a recreational fisher holding a large Walleye and a server holding two plates of fish and chips.

The last day of the meeting is Lake Erie. For many, this is the most important set of discussions and reporting out because this is where the stock assessments are presented about commercial and recreational targets for Walleye and Yellow Perch within the different management zones. Lake Erie supports the largest fishery with the lake containing about 50% of the total fish biomass for all the Great Lakes. Towns on the Canadian north shore such as Port Dover and Part Stanley were founded because of commercial fishing. Because of this valuable fishery, there is conflict between recreational and commercial fishing because each has to be included into the total allowable catch (TAC). In Ohio, commercial fishers may take Yellow Perch, but not Walleye, which has been designated entirely to the very valuable recreational sport fishing. Any Walleye that is sold in Ohio is almost exclusively from Canadian commercial fishing operations where Ontario puts most of the total catch to them. As such, Yellow Perch is widely available in Ohio fish and chips restaurants but Walleye more on the Canadian side.

A small research vessel trawling for fishes and some resultant catch.

The upcoming 2024 field-year is Lake Erie, with planning having taken place for many months. We have 3 cruises to track the patterns of productivity across the lake and are coordinating with USEPA to ensure we have additional lower foodweb data this year. The hope is that this can be used, along with other monitoring programs for prey-fishes, to create models of the trophic transfer in this very important system.