A new study shows that Chinook salmon introduced into Lake Michigan by Wisconsin hatcheries are performing well in the waters.
The multi-year study looked at salmon catches and specifically attempted to track farmed and stocked salmon as they were introduced over the years by various natural resources departments across the region. The study shows that fish raised and released in Wisconsin have had an above average chance of survival until it was time to spawn. Wisconsin bred and released fish accounted for some 49 percent of stocked fish harvested throughout the lake and 57 percent of the stocked fish taken in Wisconsin waters.
DNR northern Lake Michigan fisheries supervisor Dave Boyarski says experts from across the region are also seeing the salmon taking a firm hold of the ecosystem and breeding without the help of the hatcheries. “Some of the rates have been upwards of 60 percent over the last few years, which is a high number of naturally reproducing fish on the lakes. So anglers are benefiting from our stocking programs, as well as the natural reproduction in some of the tributary streams to Lake Michigan and Lake Huron.” Most of the tributaries to Lake Michigan in Wisconsin lack the structure and clarity required for the salmon, so stocking is still essential to the fish’s population.
Boyarski says the study shows that the fish are migrating heavily to follow prey species. “And what we’re finding is, in the summertime, that fish could have come from anywhere in Lake Michigan. Be it state of Michigan, Illinois, Indiana, Wisconsin, or even Lake Huron.”
The study also found that natural reproduction is strong now, that may change over the next few years. Lower lake levels and stream flows during 2102 and the subsequent harsh winter from 2013-2014 hurt the populations of both the salmon and the prey fish in the lake. Only 37 percent of the fish from the 2013 year class were wild fish.
Boyarski says experts from around the region will be using this data to help refine how and where they stock the salmon over the coming years. They will also be keeping an eye on the future of the lakes as more invasive species threaten the ecosystem. “It takes a lot of effort and a lot of funding to pull this off, a lot of working with partners, and I think what you’re seeing in these results is information that’s really going to manage this fishery into the future and that it’s a good fishery.”