Restoring the shore and fish habitat in Michigan inland lakes: Part 1
A visit to Paw Paw’s natural shoreline demonstration project reveals the creation of microhabitats, or safe places, for juvenile fishes. Studies show that bluegill, largemouth bass and other fish use these “edge” habitats to increase their feeding rates.
Previous Michigan State University Extension articles have provided information on the natural shoreline movement in Michigan. These articles have highlighted the many benefits of preserving or restoring native vegetation along shorelines including erosion control, pollutant runoff reduction and food and cover for birds, butterflies and frogs. However, we shouldn’t forget the benefits to fish and fishing!
Joe Nohner, a doctoral student in the Department of Fisheries and Wildlife at Michigan State University, is focusing his research on the importance of vegetation and cover to largemouth bass populations. During a recent visit to the Village of Paw Paw’s natural shoreline demonstration site, Joe noticed that young fish were utilizing the spaces created by restored emergent and wetland vegetation. These plants were planted at the toe of the bank near the water’s edge and are, as intended, moving out onto the lakebed – creating spaces, or microhabitats, for juvenile fishes.
These microhabitats are often used by fishes as they go about their lives seeking prey, escaping predators, laying eggs or simply resting in a safe place. While it is all too easy to think of lakes as a giant bathtub that is stocked with fish and from which fish are caught, the reality is that most of the fish we catch or see in lakes come from natural reproducing populations. These young fish face incredible odds just to survive their first year as they avoid predation, eat as much as possible to outcompete their siblings – or grow big enough to eat them! They must also add enough muscle and fat to survive a long, cold winter under the ice.
How do they do all of this? Scientific studies show that bluegill, largemouth bass and other fish use the edges of habitats to increase their feeding rates. Hiding amongst vegetation allows them to ambush prey and likely saves fish from expending energy to avoid predators themselves. Microhabitats provide many such edges for fish, both small and large, to utilize. When a potential meal swims by, fish will swim out, catch and eat their prey and return to their hiding place to digest their meal. For young fishes, vegetation and deadfall wood (coarse woody habitat) offer increased numbers of small prey items – such as the larvae of aquatic insects. Nohner’s research is focused seeks to quantify the importance of these microhabitats to fish growth rates and to healthy fish populations.
Unfortunately, these important microhabitats are often lacking in our inland lakes and streams due to shoreline development. The removal of native vegetation and hardening of shorelines with vertical sea walls or rock riprap leaves young fishes with few places to hide. One benefit of natural shoreline restoration using native emergent and wetland plants is the creation of “safe places” during the juvenile stages of a fish’s development.
To view interesting underwater videos of Largemouth Bass behavior and to learn more about Joe’s research, visit his blog and website. Watch for Part 2 of this article to read about Joe’s preliminary findings.