At least 50 percent of Chinook salmon found in Lake Michigan over the last five years have been naturally reproduced, according to the Milwaukee Journal Sentinel. Despite some high and low population years, both in mass and quantity, trends surrounding wild Chinook have been overwhelmingly positive. Over the past several decades, Chinook have proven that, under the right circumstances, the species can have very productive years.
One of these circumstances is alewife populations, as they are the primary food source of salmon. The Michigan DNR has focused greatly on balancing this predator-prey relationship so as to avoid the overpopulation of either species. Alewives are a vital part of the ecosystem and therefore need to maintain population sizes to feed the prized king salmon.
In hopes of preserving this balance, salmon stocking was scaled back for the past several years due to historically low alewife populations. However, 2022 saw a return of dead alewives washing up on shores, something that is typically only seen when populations are high. This is because alewives often migrate earlier when populations are high. The early migration can lead to stress and disease for the fish, causing many to die early on in the season and later wash up on the shore. Several extreme weather events and temperature fluctuations have also impacted habitat quality, creating conditions that are inhospitable to alewives, resulting in large fish kills.
While the occasional alewife washing up on the shore isn’t uncommon, the amounts strewn across shorelines in 2022 were so large that they had to be removed using bulldozers, according to Michigan Live. Based on current population sizes and the climbing alewife populations, the Michigan DNR believes that it is once again time to stock the lake with more Chinook. According to Michigan Live, Jay Wesley, the DNR’s Lake Michigan basin coordinator, says, “We’ve reviewed this and agreed to go up to a million fish.”
Before stocking can begin though, the action must be approved by the Great Lakes Fishery Commission’s Lake Michigan Committee, which has wanted to hold off on increased stocking for the past several years. However, with alewife populations as high as they are and Chinook being a popular catch in the lake, hopes are high for how the committee will vote this year.
If the proposal is approved, Michigan Live reports that this “would be the first major Michigan Chinook stocking increase since the late 1990s, when 3 million fish were stocked.” The final decision should be known by September of 2022, and hopes are high for both the Michigan DNR and local anglers who are hoping to have another productive salmon year, with even more guaranteed in the future.
Juvenile salmon return to their spawning water after three years, so if approved, the benefits of a 2022 stocking event would not be able to be measured until 2025. However, previous stocking events and high years have proven to benefit salmon populations in the season following their return to freshwater.