Photo by Mike Gnatkowski

Some things never change. Some things always change. Rarely does something that never changes always change. Lake Michigan's amazing salmon and trout fishery is one of those things that starts each fishing season pretty much the same, then runs a different course as the summer progresses. Having fished the big lake as a professional chartaer captain for 25 years, I can truthfully say that while similarities occur, I have never seen one season that comes close to duplicating another.

Over the past 10 years, lakewide stocking rates of salmon and trout have remained consistent in terms of total fish released. However, five years ago, chinook planting was drastically cut back when it was thought the big predators were taking too big a bite out of the alewife forage base. When the food supply dwindled, the chinooks became stressed and developed bacterial kidney disease (BKD), a deadly malady that decimated their numbers in their second and third years of life.

To combat BKD, the biologists from the four states surrounding Lake Michigan determined a course of action that would reduce the number of chinooks in the lake to give the alewife population a chance to rebound. The hope was that those fish stocked would remain healthy, and in the end result in a larger proportion of adult chinooks avoiding BKD, and maturing to 4-year old adults.

Fishing results indicate more large chinooks being caught during the past few seasons, but the fishery managers are still studying the findings of test-netting and shocking surveys. The early indications are the number of adult chinooks returning to stocking points have been shrinking in each of the past five years. This may indicate that while more chinooks are growing to adult size, a significant percentage of each year's planting is still dying off at an earlier age.

However, this problem has not affected overall fishing success lakewide since increased planting of cohos and rainbow trout has made up the shortfall in chinook numbers. In like manner, planting additional rainbow trout and brown trout made up for a shortfall of cohos available for stocking in the spring of 2004.

Summarizing the recent plantings that affect the fishery each season is a bit complicated. Although Illinois annually stocks around 900,000 fish, this is not enough to assure good fishing in a pond the size of Lake Michigan, which is about 300 miles long, 50 miles wide and more than 1,000 feet deep in a few places. In order to assess the number of salmonids available on a yearly basis we also must take into consideration those fish stocked by Michigan, Indiana and Wisconsin. Since none of these fish stay in their home waters for long, they contribute heavily to the Illinois fishery.

Steve Robillard, an Illinois Department of Natural Resources fishery biologist assigned to the Lake Michigan Salmonid Task Group, provided us with an overview of the situation.

Since the cohos stocked by Michigan -- usually 1.5 million -- contribute the most to the overall fishery, it is significant that their stocking program was disrupted last year when 500,000 cohos were released earlier than usual due to renovations under way at the Platte River Hatchery. Last fall, a considerable number of small cohos showed up in test surveys of the Chicago harbors, and were probably part of that early Michigan release. If so, it means there will be less cohos in the lake this summer.

Adding to the problem was the die-off of another 500,000 cohos in a Michigan hatchery due to a pump failure. Without doubt, coho numbers will be down this summer, but with less pressure on the forage base, those fish that are present should be larger. Coho salmon annually comprise 80 percent of the total Lake Michigan sport catch.