MICHIGAN—Large woody debris is an important feature of a healthy aquatic habitat. That’s why USDA Forest Service staff are building wooden structures—called fish cribs—to benefit ecosystems in lakes on the Hiawatha National Forest.

A multidisciplinary Forest Service team recently gathered for several days at Gooseneck Lake, 33 miles northeast of Rapid River, Michigan, to help Hiawatha National Forest fisheries biologists install 40 fish cribs on the ice. Funded through the Great Lakes Restoration Initiative, this aquatic habitat project is part of efforts to accelerate protection and restoration in the Great Lakes watershed, the largest system of fresh surface water in the world.

“When the ice melts in the spring, the log crib structures will sink to the bottom, where they will increase cover and habitat for aquatic organisms,” said Luke Langstaff, a fisheries biologist with Hiawatha National Forest.

Fish cribs are log structures designed to provide increased cover and habitat to many aquatic organisms by adding to naturally occurring large woody debris such as fallen trees. As plants and animals begin to utilize the new habitat, the Gooseneck Lake food chain will benefit. Invertebrates will feed on the new algae, attracting forage fish, and those forage fish will attract predatory game fish species.

“Improved habitat benefits not only the fish—it also means anglers have a better opportunity to catch a variety of fish species,” said Forest Service fisheries biologist Eric Miltz-Miller.

In June 2021, 139-acre Gooseneck Lake was stocked with 5,250 fingerling walleyes by the Michigan Department of Natural Resources. Surveys in 2021 found other fish in the lake, including northern pike, largemouth bass, smallmouth bass, pumpkinseed sunfish, bluegill, rock bass and brown bullhead.

Planning and timber delivery were done in fall 2021. When crib building began in February 2022, logs were loaded using a skid steer onto snowmobiles hauling sleighs, which transported supplies onto the frozen lake where team members constructed the cribs. Construction took eight days, thanks to the efficiency and skill of the team.

According to Miltz-Miller, there is a science to deciding which lakes could most benefit from installation of fish cribs.

“We use data and surveys regarding fish species and biomass, along with historical large woody debris data, to determine which sites can benefit from fish cribs,” Miltz-Miller said, adding that the Hiawatha fisheries team anticipates using scuba gear, cameras, and surveys to measure the benefits of the Gooseneck Lake fish cribs.

Hiawatha National Forest’s lakes were deprived of large woody debris due to intense deforestation beginning in the late 1800s. Addition of cribs is just one of several ways that the USDA Forest Service works to improve national forest ecosystems and watersheds. In 2023, the Hiawatha National Forest fisheries program will be installing fish cribs in Round and Cookson lakes. Installation of fish cribs on Fish Lake is tentatively planned for 2024.

Launched in 2010, the Great Lakes Restoration Initiative provides resources for federal agencies and their partners to strategically target the biggest threats to the Great Lakes and accelerate progress toward long-term restoration goals for this important ecosystem.