Fry, Fingerlings and a First-Class Fishery

By Jake Brown

For centuries, the water surrounding our beautiful peninsula has served as a means for transportation, commerce, recreation and food by way of fishing. Managing all that water and the fish that swim in it can be quite the task, but for those working at the Michigan Department of Natural Resources (MDNR), it is their passion. In Manistique, the Thompson Fish Hatchery plays a vital role in the sustainability of the fish that swim in our Great Lakes.Aerial view of the Thompson Fish Hatchery fish tanks

Located in Manistique, Thompson State Fish Hatchery started in 1919. Over the years, the hatchery has gone through numerous changes and upgrades. In the very early days, water was diverted from local creeks to give fresh water to the young fish. Water is sourced from several wells and a spring to feed concrete rearing tanks as well as their six large rearing ponds with fresh, cool water. Each upgrade allows the hatchery to raise more fish and reduce the chance of mortality to keep our waters stocked with numerous healthy fish species.

The process of raising and stocking over 1,000,00 trout, salmon, walleye and muskie a year begins with egg collection. Trout and salmon eggs are sourced from the little Manistee River and arrive to the hatchery in the spring and fall while walleye eggs are collected locally in Little Bay De Noc through trap nets during the spawning runs in early spring. Once eggs hatch, “fry” quickly grow while technicians monitor them carefully for disease, proper feeding and water quality. Fry are raised in either concrete tanks or go to rearing ponds, depending on the species. After reaching a few inches in length, juvenile fish known as “fingerlings” grow until they are healthy enough to be moved to Michigan lakes and streams. Every step is carefully completed to ensure the best chance of survival for each fish species.

To grow from fry to fingerling, fish need food and lots of it.

“Our trout and salmon will eat over 100,000 pounds of food each year and are fed constantly. When they are small, we feed every 10-15 minutes. As they get larger and are moved to the outdoor raceways, they are fed every hour or two,” explains MDNR Manager, Randy Espinoza.

Once fish get healthy and large enough, fishery technicians use special transportation vehicles to move fish to live their lives in the wild. Stocking takes a great deal of time. Most of it occurs during April and May with technicians driving around 16,000 miles to stock our lakes and streams with trout and salmon. Walleye are stocked in the summer and muskie are stocked in the fall.

Indoor fish tanks at the Thompson Fish Hatchery
Indoor fish tanks at the Thompson Fish Hatchery

How can anglers assist the hatchery and fisheries biologists in the process? Simply buy a fishing license. Not only does this simple task allow you to be a legal fisherman but the funds generated through the sale of hunting and fishing licenses are directly used to fund hatchery operations and projects.

“We are mostly funded by hunting and fishing license fees. It’s the people buying those licenses that are making this possible,” Espinoza commented.

Anglers can also assist hatchery operations by reporting their Great Lakes trout or salmon catch if the fish is missing its adipose fin. That is the small fleshy fin located between the dorsal fin and the tail.  A missing fin signifies two things: first it tells everyone that it is a hatchery fish; second, many of those fin clipped fish also have a small metal tag in their snout. In some boat ramp locations, signs are posted asking anglers to supply the heads of their catch so researchers can scan it for those small tags identifying the age of the fish, the hatchery it came from and its stocked location.  Anglers that supply heads receive a letter from the MDNR providing information about the fish they caught. This whole interactive process can provide quite an insight into the lives of fish in our Great Lakes.

If you’re interested in seeing the process yourself, Thompson Fish Hatchery (944 S State Highway M149, Manistique) is a self-tour facility open for no charge to the public from 7:30 am to 3:30 pm daily. There you will find a “yellow fish road” that leads you through the outside of the facility with interpretive signs providing information about the processes. The facility features a tourist room with a video describing the process of raising salmon and trout. Located only a few short miles from the popular tourist destination of Kitch-iti-kipi, adventurers can experience a full day of exploring Michigan’s beautiful fish and outdoors. For more details, visit