Angler Citizen Science

Fishing for answers

Anyone who fishes the Great Lakes regularly can tell you that the only constant in a fishery is change. To make things even more complicated, a long list of non-native species has invaded the lakes, overturning long-standing food webs and changing the behavior and survival of valued fish.

Anglers can do their part to help scientists understand how economically valuable salmon, trout, walleye, and other species are adapting to these shifting conditions. Michigan Sea Grant and partner groups — including Wisconsin Sea Grant and Michigan State University Extension — are offering several citizen science programs that anglers can contribute to during the fishing season.

Huron-Michigan Diet Study: What are fish eating?

As invasive species shift the Great Lakes food web, predators are changing their feeding habits. The Michigan-Huron Diet Study enlists anglers to contribute stomachs from all types of predatory fish caught in Lake Michigan and Lake Huron.

If you fish early or late in the year, late at night, or in places away from crowds, your contribution may be especially useful. To avoid bias, it is important that you collect stomachs in the manner described below. Even empty stomachs are very important because a high percentage of empty stomachs means that fish are having trouble finding food.

If you would like to participate:

  • Decide if you will collect stomachs from this fishing trip.
  • Remove stomachs from ALL fish of each species you are collecting.
  • Place stomach and ALL contents into plastic bag with data tag.
  • Freeze or ice stomachs immediately and deposit in freezer at drop site.

Freezers at collection sites are operated in conjunction with Michigan DNR. Other partner groups include Michigan State University and U.S. Geological Survey. This project is being funded by Great Lakes anglers and conservationists. Donors include the Grand Rapids Steelheaders Foundation and Grand Haven Steelheaders Foundation in addition to many generous individuals.

Materials for stomach collection include:

The Great Lakes Angler Diary app: Report your catches online

The Great Lakes Angler Diary is a web-based app that can be accessed from any computer or mobile device at The app allows you to record data on all salmon and trout species, cisco, walleye, muskellunge, and lake sturgeon. Use the app to record information from fishing trips and share that information with Michigan Sea Grant. You can participate by taking the following steps:

  • Sign up for the program by emailing
  • Receive a unique Volunteer Number via email.
  • Register online at using your Volunteer Number.
  • Record as much — or as little — information as you would like during the fishing season.
  • Answer a short survey at the end of the year.

The survey will help scientists determine how to use your information. The more details you record, the more useful your data set will be.

Salmon Ambassadors: Where are the wild salmon?

Since 2013, volunteers have been measuring Chinook salmon and checking for adipose fin clips that indicate stocked fish. Salmon Ambassadors commit to collecting data on each and every Chinook salmon caught from their boat during the fishing season. As of 2017, anglers are encouraged to use the Great Lakes Angler Diary app to enter all of the Chinook salmon data required for the Salmon Ambassadors program. If you need paper data sheets, you can print your own from the Salmon Ambassadors page.

Fish finders: Where’s the bait?

Long-term monitoring of baitfish in Lake Michigan has shown dramatic declines in overall availability of baitfish in open water. The decline of alewife has been particularly important to the salmon fishery because Chinook salmon rely almost entirely on alewife for food.

Anglers can submit bait ball images from their own fish finders by emailing them to or recording them using the Great Lakes Angler Diary app. Just be sure to include the following on your screen display in each bait ball image:

  • Date
  • Time
  • Depth
  • Longitude and latitude

Fish finder sensitivity should be set so that you are certain marks do not represent clouds of plankton or suspended debris. Images should clearly depict large schools of bait fish, as opposed to images of scattered bait or individual large fish. These images may be useful in helping biologists determine where and when alewife and other baitfish are most abundant.

Support for citizen science on the Great Lakes

In addition to the agency and fishing organizations mentioned above, two additional groups have been tremendously supportive of citizen science. Programming for the Great Lakes Angler Diary app was funded exclusively by Detroit Area Steelheaders and in-kind support from Brenton Consulting, LLC. Citizen science would not be possible without the contributions of anglers at every step of the way.

Due to measures enacted to slow the spread of COVID-19, the infectious disease caused by novel coronavirus, Michigan State University researchers and other collaborating agencies are unable to collect stomachs from anglers at this time.

This means that we will be relying on anglers to collect their own stomachs until further notice. Most freezer drop sites will be unavailable for the immediate future, so we are asking anglers to keep their stomachs frozen in personal freezers until social distancing guidelines are relaxed and public freezer drop sites are reopened.

– Diet study project team, April 9, 2020