Revisiting stocking policy for Lake Michigan

Fisheries managers are now reconsidering how many salmon and trout are stocked in Lake Michigan each year. Possible effects of stocking options will be shared with the public on April 14 in Benton Harbor.

At many Lake Michigan ports, the difference between 2010 and 2011 was remarkable. While the late summer king salmon migration never seemed to take off in 2010, the 2011 season was very good by all accounts. The kings were bigger, the cohos were bigger, and there were plenty of fish to go around.

Why did the lake see such an abrupt turnaround? The huge alewife year-class of 2010 certainly played a role, but large alewife year-classes have been few and far between in recent years.  Alewife recruitment is only partially dependent on the number of adult alewife in the lake, which makes large year-classes difficult to predict.

The Quantitative Fisheries Center at Michigan State University is using what we know about alewife recruitment, salmon and trout abundance, and feeding rates to predict future fishing success. This is part of a broader effort to identify possible outcomes under a variety of different stocking policies. This Structured Decision Analysis (SDA) is a complex process, but the implications for anglers are huge. 

By fall of 2012, fisheries managers on the Lake Michigan Committee of the Great Lakes Fishery Commission will make a decision regarding the total number of salmon and trout to be stocked in Lake Michigan over the next several years. Managers will use the SDA, red flags analysis, current conditions in Lake Michigan and angler feedback to inform their decision.

Anyone interested in the future of the Lake Michigan fishery is welcome to join in the discussion of stocking policy that will continue for several months. The next step is evaluation of specific stocking policies. Possibilities might include continuing with the current stocking rate, lowering the number of Chinook salmon, or all salmon and trout stocked in Lake Michigan. The policy could also include triggers like the weight of age 3+ Chinook salmon in the fall to set a specific policy in motion.

Even though 2011 was a great season for Lake Michigan, the risk of a fishery collapse similar to what happened in Lake Huron is a very real possibility according to early modeling results. Stocking is one of the most influential tools managers have available for influencing the lake, but even stocking has a limited influence in a complex system dominated by exotic species. After all, stocking levels were the same in 2010 and 2011, but the resulting fisheries were anything but similar.

Mark your calendars for Saturday, April 14, 2012 if you would like to meet with fisheries managers from Michigan, Indiana, Illinois, and Wisconsin to learn more about the risks associated with each stocking option and provide your input. The meeting will be held at Lake Michigan College in Benton Harbor, Michigan. A full agenda and options for online participation are available on the Michigan Sea Grant website

Presentations from Jay Wesley of the Michigan DNR and Dr. Michael Jones of MSU’s Quantitative Fisheries Center are also available. These provide an overview of past and current status of Chinook salmon and forage fish monitoring, as well as in-depth discussion of the SDA process.