Following more than a year of deliberations with constituents, scientists and fishery managers, the Michigan Department of Natural Resources announced that it agrees with an inter-jurisdictional recommendation by the Lake Michigan Committee to reduce Chinook salmon stocking by 50 percent lake-wide. The Lake Michigan Committee is comprised of fisheries managers representing Michigan, Indiana, Illinois, Wisconsin and five Michigan tribes that are party to the 2000 Consent Decree.
Under the lake-wide plan, the 3.3 million Chinook salmon annually stocked in total in Lake Michigan by the four states would be reduced to 1.7 million starting in 2013. “This reduction is essential in helping to maintain the balance between predator and prey fish populations in Lake Michigan,” said Jim Dexter, Michigan DNR Fisheries Division chief. “These reductions are necessary to maintain the lake’s diverse fishery.”
A key factor to Lake Michigan’s current and potentially precarious ecosystem balance is an increasing presence of wild Chinook salmon in Lake Michigan. Streams in Michigan continue to produce significant numbers of naturally reproduced Chinook salmon and lake-wide estimates show more than half of the lake’s Chinook population is of wild origin. Because of the significant natural reproduction occurring in Michigan, the DNR will shoulder the majority of the stocking reduction. Michigan will reduce stocking by 1.13 million spring fingerlings, or 67 percent of the 1.69 million recently stocked by the state. Wisconsin will reduce by 440,000; Indiana will reduce by 25,000; and Illinois will reduce by 20,000.
This marks the third time in recent history that stocking in Lake Michigan has been reduced by the agencies. Previous decisions to reduce stocking in 1999 and 2006 resulted in maintaining and improving catch rates. Fisheries managers believe this is because natural reproduction continues to fill any available predatory space. The decision to reduce stocking is part of an adaptive management strategy that includes a feedback loop that will monitor certain indicators in the lake, such as Chinook salmon growth. If conditions improve or get worse, stocking will be increased or decreased accordingly, and more quickly. “This will give the DNR more flexibility to adaptively manage the lake,” said Jay Wesley, Southern Lake Michigan Unit manager. “Traditionally, we have made changes in stocking and waited five years to evaluate it, and another two years to implement changes. Now we have the ability, through a defined and accepted process, to make changes as they are needed.”
The DNR’s Fisheries Division will discuss with constituents this fall how each stocking location will be affected by the stocking reductions. Future site-specific stocking levels will be based on natural reproduction, net pen partnerships, broodstock needs and hatchery logistics. Every existing stocking location should expect a reduction.