Guest columnist Dick Osgood.

Zebra Mussel’s Ugly Cousin

We were all disappointed last summer to learn of the discovery of zebra mussels in Lake Minnetonka. After a decade of warning that we were inadequately protected, zebra mussels invaded our lake. Now, Lake Minnetonka, along with Gull Lake, Prior Lake, the Alexandria Chain of Lakes and Mille Lacs Lake, are ‘super-spreaders’ and I would not be surprised if ten additional lakes have zebra mussels discovered this year.

Lake Minnetonka and all of Minnesota’s lakes remain under-protected.

We have yet to realize the full impacts of zebra mussel in Lake Minnetonka. I expect substantial increases in the zebra mussel population over the next two or three years. All hard surfaces will be coated with zebra mussels, shells will wash up on lakeshores, fish habitat will be degraded, water clarity could increase, milfoil growth will expand – it will be a headache we will have to learn to cope with.

So what could be worse?

Let me introduce zebra mussel’s ugly cousin, the quagga mussel. The quagga mussel is related to the zebra mussel, but its impacts will be more severe. The quagga mussel can grow on all surfaces, including muck, wood and vegetation, which are extensive in Lake Minnetonka. The quagga mussel grows in deeper water than zebra mussel. The quagga mussel reproduces throughout the open water season, whereas the zebra mussel reproduces only in mid-summer. In lakes where both mussels have been introduced, the quagga mussel takes over. As bad as zebra mussel will become, the quagga mussel will be worse.

Here is the issue – despite these being two distinct species mussel genus with different, severe impacts, the Minnesota Department of Natural Resources has classified these as the same animal.
Now that Lake Minnetonka has zebra mussel, more protection efforts are being focused on boats leaving the lake to help keep zebra mussel from spreading, meaning less attention will be spent on boats entering Lake Minnetonka. Because zebra and quagga mussel are classified as the same animal, the quagga mussel is not recognized as a separate threat.

Lacking this official distinction, inspectors and others may let down their guard for this new invader.

The quagga mussel has been in Lake Pepin and the Duluth-Superior Harbor and since 2006 and in the Mississippi River at Winona since 2005. Because the quagga mussel is not recognized by our regulatory programs to be different than the zebra mussel, Lake Minnetonka is inadvertently exposed. This oversight will, I fear, lead to a second wave of devastating mussels in Lake Minnetonka and across Minnesota.

It is tragic how we are learning of all the protection methods that are not effective – voluntary compliance, miniscule fines, minimal enforcement, practically non-existent oversight of angling tournaments and special events – if we really want to protect our lakes, we should be as aggressive with our protection actions as invasive species are in exploiting our ineffective protection measures.

Unfortunately, we now know the protections we had for Lake Minnetonka were not adequate. Because these protections have not improved, we can very well expect the zebra mussel’s ugly twin, the quagga mussel, is not far behind.