In Michigan, any body of standing water other than the Great Lakes generally is defined as an inland lake. This includes both natural and man-made water bodies. According to most sources, Michigan has 15,800 lakes and ponds that are at least two acres in size.

The larger inland lakes, especially those over 1,000 acres, present a special challenge to Department of Natural Resources fisheries managers. Although theses large lakes support some of the most important, productive fisheries in the state, their size makes detailed biological assessment of fish populations and harvest difficult and costly.

Beginning in 2001, however, the DNR Fisheries Division launched a statewide program designed to improve assessment and monitoring of fish communities and fisheries in Michigan’s largest inland lakes.

Known as the Large Lakes Program, the initiative is targeting 92 inland lakes that are 1,000 acres of more in size.

Combined, these lakes total about 360,000 acres and provide a significant proportion of the total fishing activity in the state. Yet, only 20 of these lakes have had modern angler harvest surveys within the past 50 years.

According to Patrick Hanchin, fisheries biologist at the Charlevoix Fisheries Research Station, lakes will be selected for sampling based on fisheries management priorities.

"Some might be sampled every five years, while others might never be sampled," Hanchin said. "Even so, lakes not selected for sampling will not be ignored. These lakes will continue to receive attention by local managers through smaller, less extensive surveys geared to answer specific management questions."

Hanchin said the current plan calls for the Fisheries Division to survey about four lakes per year over the next 10 years.

"Conducting large lakes surveys will allow the division to do a more complete job of managing the state’s fisheries," Hanchin said, "and though it is important to know about the fisheries of a single lake, we can make better management decisions from the pool of information that we gain from sampling multiple large lakes."

Houghton Lake, Michigan’s largest inland lake at 20,075 acres, was the first lake to be surveyed under the new program. Houghton Lake was surveyed from January 2001 through March 2002. During this same period, surveys were completed at Michigamme Reservoir in Iron County and at Crooked and Pickerel lakes in Emmet County. In 2004, Grand Lake (Presque Isle County) and Long Lake (Presque Isle and Alpena counties) were surveyed as well.

Earlier this year DNR fisheries biologists began a study of Lake Gogebic in the western Upper Peninsula. Lake Gogebic, which is the largest lake in the U.P. and spreads over almost 13,400 acres, is notable as one of Michigan’s large lakes because of its reputation as a "walleye factory."

"Although Lake Gogebic originally had no walleye, and was dominated by smallmouth bass, the walleye density has at times been one of the highest of any large lake in Michigan," Hanchin said. "With this survey, we hope to accurately assess the current state of the walleye population, so that managers have all of the necessary information for sound management."

According to District Fisheries Biologist George Madison, the survey work began right after ice-out. The netting operations targeted northern pike, walleye and other spring spawners, although the biologists conducted counts of all species caught.

"Our crews started placing the nets at various locations around the lake depending on where the fish were spawning," Madison said. "We started with northern pike which spawn in marshy habitats and then moved the nets to the rocky shoals where walleye are found. The last species we targeted were yellow perch and smallmouth bass."

Madison said more than 60 nets were used in the survey.

"The crews were out every day, from early morning to late evening, regardless of the weather," Madison said. "At the peak of the survey, we had four netting crews setting and tending the nets, plus transferring the fish to processing stations on shore where other fisheries staff would record the weight and size of each fish, then apply a metal jaw tag. Each net-boat crew could tend about 10 fyke nets and then move those nets to new locations as needed."

Tagged fish also are fin clipped to help evaluate tag loss, Madison said.

The survey continues this summer as the number of fishing boats on the lake will be counted by aircraft and a creel clerk working from a boat will be collecting angler success data. A winter creel survey also is planned.

"The Large Lakes program is important because we are learning about lakes that provide a significant proportion of the fishing activity in the state," Hanchin said. "Some of these lakes have been neglected in the past because the effort required to make detailed biological assessments of the fish populations was more than local fisheries managers could handle. Through the Large Lakes program, we are pooling state resources (personnel and equipment) so these valuable systems get the attention they deserve."