Great Lakes salmon fishing ranks among Michigan's premier angling opportunities. Every spring and summer, tens of thousands of anglers head onto the lakes from ports throughout Michigan, hoping to catch coho and chinook salmon.

But the coho and chinook have not always called the Great Lakes home. In the 1960s, the Great Lakes saw an overpopulation of alewives--small, silver, non-native fish that entered the lakes through shipping channels. As alewife numbers grew out of control, they died and washed ashore on Great Lakes beaches by the millions each spring. Department of Natural Resources leaders introduced salmon to eat the alewives, and this successful importation also worked to create a billion-dollar sport fishery that today draws anglers and tourists from all over the world.

Salmon are an anadromous species, which means they live in lake environments but spawn in rivers and streams. Salmon live in the Great Lakes as adults for approximately four years. Each fall, when cooler temperatures and rainfall trigger their instincts, the adults head into the state's major rivers to spawn. Unlike most fish, salmon die after spawning.

The fall salmon run provides recreational excitement for anglers of all ages. This is the time when anglers who do not own boats large enough to navigate the Great Lakes have an opportunity to catch some of Michigan's largest, most powerful sport fish.

The fall salmon run also provides fisheries managers with the ingredients for the next generation of salmon. Weirs and holding pens in five locations along Lake Huron and Lake Michigan tributaries collect thousands of the migrating fish as they move upstream.

"The work done at the weirs is the cornerstone of Michigan's salmon program," said DNR Fisheries Division Chief Kelley Smith. "Without the weir program, we would not be able to maintain Great Lakes salmon."

Each female salmon holds 4,000 to 7,000 eggs, called roe. DNR employees gather the fish in holding pens and net them individually to collect the roe from the females and sperm, called milt, from the males. When the roe and milt are combined and the eggs fertilized, the mix is taken to state fish hatcheries for incubation. The vast majority of Michigan's salmon begin their lives in hatcheries.

Michigan's six state fish hatcheries are open to the public, and most offer guided tours and educational programs at on-site interpretive centers. Wolf Lake Hatchery in Kalamazoo, Platte Hatchery near Honor, and Thompson Hatchery near Manistique are responsible for producing coho and chinook salmon.

The hatcheries deliver up to 5.6 million chinook and coho salmon each year. They supply all of Michigan's salmon, as well as sending several hundred thousand fingerlings to Indiana and Illinois for Great Lakes stocking programs.

Chinook salmon hatch in November and are released into designated rivers the following May, but coho live in the hatcheries for up to a year-and-a-half before they are released.

"A large portion of our time, space and energy at the hatcheries is devoted to trout and salmon," said DNR Hatcheries Manager Gary Whelan. "Recent renovations throughout the hatchery system allow us to monitor and adjust every step of the hatching and rearing process--from water temperature and quality levels to flow rates in the raceways, to disposing of fish wastes. Michigan's hatchery system is among the best in the nation, in terms of being environmentally responsible and producing healthy, high-quality fish."

Although many of the adult salmon in the rivers each fall are caught by anglers, this harvest represents only a fraction of the total salmon population. The rest spawn and die.

To address the waste issue, the DNR works with a contracted company at fish weirs along Lake Huron and Lake Michigan, which processes the salmon into food.

"This program is a very successful partnership," said DNR Fisheries Division Chief Kelley Smith. "It prevents waste of a nutritious food source, and helps fisheries managers focus on their work to ensure future generations of Great Lakes salmon."

The fall salmon run continues through October and early November on many Michigan rivers. For information on where to see the salmon run or to visit a weir or hatchery, call 517-373-1280 or visit the DNR Web site, www.michigan.gov/dnr.