Otter Lake and its dam have been the source of much discussion, pro and con, in the past year. A look at its environment (physical and chemical), history of stocking and fish surveys, current fishery status and management operations will give an insight on the effects of the 40-year old dam.
It is located in east-central Houghton County, within a quarter-mile of Baraga County, and covers 890 acres. It lies at an elevation of 612.2 feet, which is only 10 feet above Portage Lake and Lake Superior. This fact makes the area downstream very susceptible to flooding. The maximum depth is 29 feet and it averages 20 feet. Twenty percent, or 178 acres, is less than 15 feet in depth. It has one named inlet, the Otter River, entering at the extreme south end. Otter Lake also has 15 groundwater springs/seeps along its west shore, which originate from the 330-foot-plus hill along its western border. The water is tannic and acid stained, being able to see down only eight feet. The pH, alkalinity, and oxygen levels are adequate for aquatic life, although there is insufficient oxygen in the bottom 10 feet.
Otter Lake has a long history of fish stocking, beginning in 1934 and the last occurring in 2012, involving three species. Walleye were the most frequently stocked in 23 of the 24 years and 15 of those being from 1978 to 2012. Tiger musky and smallmouth bass were each stocked three times.
Twenty-one fisheries surveys have been conducted on Otter Lake, with the first being in 1921 and the most recent in 2004. Sixteen of these have been since construction of the Otter Lake Dam and diversion. The 1921 survey was a brief two day peek at fish populations. The 1925 survey was the first comprehensive survey and found 18 different species. The 1955, 1960, and 1970 surveys found healthy, thriving, and diverse fish populations, which included northern pike, walleye, perch, sauger, large and smallmouth bass, black crappie, and bluegill. One interesting species captured was cisco or lake herring, which is a Great Lakes species. They were trapped there when lake levels receded centuries ago. My theory on why they persisted is, Otter Lake has sufficient cold ground water from the many springs/seeps previously described, to sustain the cold water necessary for cisco to thrive. After the 1977 survey, they were gone. The 16 surveys done after the dam construction were made primarily because of complaints of poor fishing. The surveys were in 1977-80, 1982-83, 1988, 1994, 1996-98, and 2000-04. These surveys showed the steelhead, burbot, and lake sturgeon runs were virtually eliminated. The once abundant sucker runs up the Otter River were also impacted. The bullhead population increased to the point manual removals were made, but had little overall effect on their total numbers.
The Otter Lake Dam & Sturgeon River Diversion was built in 1974-75 at a cost of $372,458. The primary intent was to alleviate flooding downstream of Otter Lake and was politically motivated. History has shown the downstream flooding has not declined, while the floods on Otter Lake are higher and last longer. Fisheries Division opposed the project, citing concerns because the walleye, lake sturgeon, steelhead (rainbow trout), and burbot runs could be interrupted, which did happen. A 1991 Fisheries Division memo, which was based on the numerous recent fish surveys, stated " to restore the fishery, the dam should be removed, as it has ruined a fabulous spring and fall walleye runs and created an abundance of bullhead habitat, resulting in their becoming the dominant species." In this fisheries biologist's opinion, the facts show the dam was harmful to Otter Lake and River fish populations, increased flooding of lake properties, while not meeting the intended objectives of reducing flooding downstream.
Dam removal would benefit fish populations, please most Otter Lake riparians, make Portage Township and Otter Lake taxpayers happy, and delight Mother Nature.