Under The Water

For seven years we have invited carp archery sport fishing in the lake to control the carp population and we must to continue doing so as an over abundance of carp are detrimental to a balanced lake ecosystem. When the program began, archery fishermen collected and disposed of 30 or more in an evening. In recent years their take have been less than 10, although we’re not sure if it’s because of a reduced population, their aim or both.

Recent photo of our neighbor Fred Rose with a carp that he caught from Lake Manitou.

Common carp are considered an invasive species in Michigan. They are “bottom feeders”, eating decaying fish, plant material, snails and mussels. They can disrupt our sport fish habitat, eating fish eggs, destroy fish spawning beds and increase turbidity (cloudy water). Their destructive nature far outweigh the benefits. This past June, one of our neighbors mentioned that they were concerned about the destruction of perch spawning beds in the water near their shore as large carp were swimming through the beds, and they wanted residents to know the correct facts about carp. David J. Jude, Ph.D., Limnologist, Fishery Biologist studied the fish population of Lake Manitou in 2011 and wrote the following:

“Common carp appear to be abundant in the lake.  This is an exotic species that can increase water turbidity, compete with some native species, and may on occasion eat eggs of natives. They should be removed legally by anyone catching them on hook and line and archers should be encouraged to remove them as well.”  Dr. Jude’s complete report can be found on the Lake Manitou Association website. http://lake-manitou.org/wp-content/uploads/2013/12/fishery_survey.pdf Thank you to Fred Rose for sharing the photo and our neighbor for asking about this topic.

Whether you call it a mussel, clam or bi-valve it’s all the same. The mussels in the next photos are Asian clams that were recently collected from Lake Manitou.



This past June, with the help from our neighbor Noah Rose, several areas of Lake Manitou were studied to identify what types of mussels inhabit the lake floor. We especially wanted to know if the invasive zebra or quagga mussels are in our lake as they are an undesirable invasive species that can easily over populate and damage the balance of an underwater ecosystem. Happily we didn’t find any. Unfortunately, only Asian clams were found and although not a native species, (indigenous to Michigan), they are not considered a danger to habitat. The majority of clams that Noah found were dead and all less than one inch in size. This is a telltale indicator of our lake ecosystem health. A monoculture, (single species) of anything in a community can suggest there are negative influences causing an imbalance and death, especially when you consider that Michigan has 45 different species of mussels. Could the use of algaecide or herbicides be a significant factor in the loss of our benthic (lake floor) organisms? Possibly an over abundance of carp have decimated the mussel population? The photo below is of an invasive zebra mussel. Quagga mussels are similar in shape. A special thank you to our neighbor Noah Rose for his interest and collection efforts.


If you would like to know more about Michigan mussels click below https://mnfi.anr.msu.edu/pdfs/FreshwaterMusselsOfMichigan.pdf In an effort to reduce the spread of invasive animals such as the zebra mussel and aquatic plants, Michigan and other states now require that all watercraft and trailers being moved from one water body to another are to be cleaned, drained and dried before being placed into another waterbody. Please help minimize the risk of bringing aquatic hitchhikers into Lake Manitou.

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