Michigan State University is leading a comprehensive study of trout, salmon and walleye diets in Lake Huron and Lake Michigan. This far-reaching effort would not be possible without the contributions of many partner organizations and individuals.

By Daniel O’Keefe

diet study instructions and picture showing detail of fish stomach. Information included in article. Video link to instructions also included in article.

Fishing season is here, and anglers want to know where the fish are biting and what they are eating.

Exotic invaders like quagga mussel, spiny water flea, and round goby have changed the Great Lakes, and gamefish are forced to adapt to resulting changes in forage fish abundance and composition. Anglers can help scientists to figure out how different fish species are adapting in different parts of Lake Michigan and Lake Huron by providing stomachs for the Huron-Michigan Predatory Fish Diet Study.

How to submit samples

To submit stomach samples after a fishing trip, follow these four easy steps:

  1. Decide if you will collect stomachs from this fishing trip. It is not necessary to collect stomachs from every fishing trip taken over the course of the year.
  2. Remove stomachs from ALL fish of each species that you are collecting. It is not necessary to collect stomachs from all species, but if you collect one stomach from a steelhead then collect stomachs from all steelhead caught during that trip. It is especially helpful to collect less-common species like steelhead, brown trout, and Atlantic salmon even if you do not collect more common species like Chinook salmon and lake trout.
  3. Place entire intact stomach into plastic bag with data tag. Make sure to include only one stomach per plastic bag. Researchers prefer intact stomachs with no punctures or holes, and will not accept ripped, open, stomachs with large holes, or prey separated from the stomach. These stomachs might be missing small or heavily-digested food items that can bias the study.
  4. Freeze or ice stomachs immediately and deposit in freezer at drop site.

Full instructions and freezer drop sites are available at MichiganSeaGrant.org/diet. Diet study signs are also posted at access sites around Lake Michigan and Lake Huron. Data tags are available at some drop sites and can be printed at home. This video also provides helpful hints on stomach removal:

Other ways to support the study

Even if you don’t participate in collecting samples, you can follow the study on Facebook to learn about the latest findings or contribute to funding the project on this CrowdPower page.

At the time of writing, $5,985 have been donated from individuals and organizations including Grand Rapids Steelheaders Foundation, Grand Haven Steelheaders Foundation, Southwest Michigan Steelheaders, Detroit Area Steelheaders, Pentwater Sportfishing Association, and Saginaw Bay Walleye Club. These donations were absolutely critical to providing student research assistant support in 2018, and donations will continue to fund Michigan State University students analyzing stomach contents in years to come.

Additional funding was awarded by the Great Lakes Fishery Trust in January 2019, which will allow MSU researchers to analyze stomach contents from trout, salmon, and walleye from 2019 until 2021.

Collaborations make it possible

The Huron-Michigan Predator Diet Study would not be possible without contributions from all the following collaborators at academic institutions and federal, state, and tribal agencies.

Michigan State University Department of Fisheries and Wildlife (Brian Roth)

Dr. Roth’s research group at Michigan State University leads the project. Students and technicians in his lab are primarily responsible for analyzing the stomach contents and the data that derives from the stomachs. In addition, Dr. Roth’s research group coordinates stomach collections with project partners on both lakes and will also collect stomachs throughout the project. MSU provides a wealth of eager undergraduate and graduate students that are excited to gain experience in the world of fisheries. They provide project updates on the Facebook page, through Instagram (greatlakespredatordiet), and Twitter (@ichthyprof).

Michigan Department of Natural Resources (Jory Jonas)

Michigan DNR has a strong interest in obtaining information on the dietary and feeding preferences of predatory fish in the Great Lakes. Information from dietary studies is used to inform parameters in fish population (growth, size-at-age) and bioenergetic (prey demands, energy transfer and resource use) models. As such, we have supported field collection efforts angler creel surveys and by volunteer anglers. Collections have occurred by coordinating within existing sample distribution and transport networks. In creel surveys, increased efforts have been made to obtain stomach samples which aren’t typically collected.

U.S. Geological Survey (Ed Roseman)

The current diet study was initiated in 2017 by the U.S. Geological Survey Great Lakes Science Center as part of Lake Huron’s Cooperative Science and Monitoring Initiative. USGS established a cooperative agreement with the Department of Fisheries and Wildlife at Michigan State University to continue sample processing and collections on Lake Huron in 2018. USGS will continue this collaborative effort in 2019-2021 by assisting with sample collections, data analysis, and reporting project results to stakeholders.

Little Traverse Bay Bands of Odawa Indians (Kevin Donner)

The Little Traverse Bay Bands of Odawa Indians is providing stomach and tissue samples from lake trout, walleye and other species collected in the northeastern areas of Lake Michigan; places that are typically less frequented by recreational fishermen and often harder to sample adequately. We are collecting these samples during our annual fish community monitoring efforts which utilize graded mesh gillnet set by our research and monitoring crews.

Grand Traverse Band of Ottawa and Chippewa Indians (Nathan Barton)

The Grand Traverse Band of Ottawa and Chippewa Indians is providing stomach and tissue samples from lake trout, and other species collected in and around the Grand Traverse Bay area of Lake Michigan. We are collecting these samples during our annual fish community monitoring efforts which utilize graded mesh gillnet set by our research and monitoring crews as well as from the commercial fishery. These samples will provide contrast to samples collected via hook and line.

Wisconsin Department of Natural Resources (Cheryl Masterson)

The Wisconsin Department of Natural Resources helped collect samples while working in conjunction with Fish and Wildlife staff at local fishing tournaments and fish cleaning stations. During the summer months, one full-time DNR employee stationed in Milwaukee recorded biological data and collected samples from angler catches of trout and salmon. The Sturgeon Bay office also provided staff one day per week, and 5 interns working out of Green Bay and Milwaukee each dedicated one day per week to the project.

U.S. Fish & Wildlife Service (Matt Kornis and Chuck Bronte)

The USFWS’s Great Lakes Fish Tagging and Recovery Lab operates a large-scale program that coded-wire tags over 9 million salmon and trout annually, and has technicians stationed around lakes Michigan and Huron collecting data on sport-caught tagged fish and their wild counterparts. The program handles 20,000 fish annually and provides an unparalleled source of stomachs and muscle samples for the cooperative diet project. Funding is provided, in part, through the Great Lakes Restoration Initiative administered by the U. S. Environmental Protection Agency.

Wisconsin Sea Grant (Titus Seilheimer)

Titus Seilheimer serves as the contact for Wisconsin anglers with questions on stomach collection and provides updates on the study at meetings including the Lake Michigan Fisheries Forum.

Michigan Sea Grant and MSU Extension (Dan O’Keefe)

Michigan Sea Grant funded an internship for MSU student Jasmine Czajka and Michigan State University Extension funded an internship for Brok Lamorandier to work on the project in summer 2018. Michigan Sea Grant hosts the diet study web page and develops educational resources related to the project.

All these collaborators play important roles in ensuring the success of the diet study, and you can too!