Local volunteers that worked on the fish crib project included members of Wildlife Unlimited of Iron County, students from Forest Park and Iron County Sheriff Department public works crews. (Ziegler photo)
By Bill Ziegler, Wildlife Unlimited of Iron County
CRYSTAL FALLS—A fish habitat crib reef was constructed at the Michigamme Reservoir off WE Energies Site 19 (Challancin’s Landing) during February.
The cribs for the reef were built by numerous local volunteers, Wildlife Unlimited of Iron County and the Iron County Sheriff Department work crew in cooperation with WE Energies. The reef was funded by a grant from Wildlife Unlimited of Iron County.
The reef is about one mile east northeast of WE site 19. The logs were placed in a crude log cabin style to form a crib eight feet by eight feet by five feet high and made out of hardwood pulp logs.
There are 22 cribs laid out in a “zigzag” pattern about 300 feet in length.
Fisheries research revealed that a reef made of a number of cribs has more habitat value than individual cribs placed around the lake, while the zigzag pattern maximizes the habitat value (increased surface area) of the reef.
With the early ice break-up, on March 20, the cribs dropped through the ice to the bottom at about 23 feet deep (full reservoir level). The cribs are placed at a depth so they are below the winter drawdown but readily accessible to game fish during the full pool periods (open water).
Michigamme Reservoir has a stable self sustaining walleye population, a good numbers of smallmouth bass and panfish.
Natural fish cover in the form of weed beds and woody cover are limited in the reservoir due to ice damage during down operations and destruction by the exotic rusty crayfish.
The reef type and design will provide a large site of woody cover and simulate a large weed bed. The primary reason for installing the crib reef was to make up for this loss of fish habitat.
A second benefit of the crib reef is that it improves the angler’s fishing success. A fisheries habitat study at similar latitude to Michigan in Ontario revealed with proper wood species selection this reef can last over a hundred years.
The reef was built with hard maple logs and pine and hardwood slab wood both long lasting species underwater.
Extensive fish utilization evaluations of the 15 reefs built in Iron and Dickinson County lakes using scuba and snorkeling was done.
Those evaluations give a good idea of what to expect for fish using this new reef. Walleye, smallmouth bass, black crappie, bluegill, rock bass and yellow perch will all use the reef, but typically not all at the same time.
Fish species groups will move into the reef area for a period of time and then move into other reservoir areas. Since walleye is one of the more dominant fish species in the overall Michigamme Reservoir fish population, it is likely they will be prominent at the reef site.
I have observed walleye and other fish species segregating in the cribs by size/age groups. While diving in walleye lakes with fish crib reefs, I have observed small walleye utilizing some cribs in the reef while larger walleye were together in other cribs.
In the next two years, Wildlife Unlimited of Iron County hopes to build one or two more crib reefs at Michigamme Reservoir dependent on future grant applications. The project is very dependent on volunteer labor and this availability of volunteers will also affect future reef projects.
If those additional reefs can be constructed it will greatly increase fish habitat and cover that is scarce in Michigamme Reservoir. Additional reefs will help spread fishing pressure out since this reef site is likely to be popular with anglers.
With adequate grant funding and volunteer participation this has the potential to produce several of the better fishing spots on Michigamme Reservoir for many years to come.