In early June, a local area resident sighted an invasive parasitic sea lamprey swimming upstream from the Crystal River Dam. The dam is located just northwest of where Fisher Lake flows into the Crystal River. It is used to balance the water flow of the river with the water levels of Fisher and Glen Lakes and also serves as a barrier to keep sea lamprey from entering Fisher Lake. Given that the lamprey was spotted upstream of the dam, it somehow crossed over the dam into the small section of the river between the dam and Fisher Lake.
This event prompted the Glen Lake Association to reach out to the U.S. Fish and Wildlife Service (“USFWS”), which agreed to inspect the dam and assess its continued effectiveness as a barrier. An inspection took place in early October, with the USFWS concluding that the dam is operating properly and should continue to effectively block sea lamprey. However, out of an abundance of caution, they installed additional water level sensors to monitor the water depth at the foot of the dam. These sensors will guide the USFWS in determining if dam adjustments need to be made to block the fish.
Sea lamprey, if left unchecked, would negatively affect the trout population in Glen Lake, as they feed on fish that have sufficient area for them to attach. As for the lamprey spotted last spring, it is likely that it came from Lake Michigan to the Crystal River to spawn and has since died. According to the USFWS, “Shortly after spawning, both male and female fall off of the nest, drift downstream, and die.” The fact that one lamprey made it upstream past the dam seems to be an anomaly and isn’t expected to be a regular occurrence.
The GLA will continue to work closely with the USFWS to ensure any sea lamprey that migrate to the Crystal River to spawn in the spring and summer months cannot make their way to Fisher or Glen Lake.
