Listen to DNR mussel expert Lisie Kitchel on The Larry Meiller Show live from 11-11:45 Aug. 29 on these WPR Ideas Network stations or online. If you miss the show, you can still listen to the archives
There are many opportunities for citizens to support conservation of Wisconsin's mussel species.
The Orion Mussel Bed, a State Natural Area along the Lower Wisconsin Riverway in Richland County, contains several rare mussel species as well as rare mayflies, dragonflies, beetles, and fish.
It's illegal to harvest any live mussels in Wisconsin, but you can collect mussel shells statewide in shallow, wadeable waters unless the species are endangered or were found on the St. Croix or Namekagon rivers. If you find live mussels, you can pick them up, check them out and place them back on the bottom. If you find invasive zebra mussels, please report the finding to your local DNR office.
Long treasured for their inner beauty - the pearls they produce and buttons made from their shells -- Wisconsin's native mussels are now recognized for their vital roles in aquatic ecosystems, including keeping our waters clean. Native mussels are food for animals including muskrat, otters, raccoon, ducks, wading birds and fish. They are our freshwater filters, removing sediment that can fuel algae blooms, pesticides, and heavy metals like mercury that can build up in fish and wildlife and the people who eat them. A single mussel can filter several gallons of water each day.
Overharvesting, water pollution, and dams that blocked the flowing water containing the food and oxygen mussels need led to mussels decline in the 20th century. Invasive zebra mussels in the late 20th century and into this century are taking a toll as well. Today, more than half of Wisconsin's 51 native mussel species are endangered, threatened or listed as species of concern. Increased awareness and appreciation of their importance, however, improved water quality due to the landmark 1972 Clean Water Act regulations, and the removal of, or passage around dams, are helping reverse their decline in some waters.
DNR, the U.S. Fish & Wildlife Service, dam owners and other partners are seeking to reverse the decline of rare species and protect common mussels as well. Mussels stranded from reservoir drawdowns are saved and put back into deeper water. Mussels propagated at the federal Genoa Fish Hatchery, and through research to find the right fish hosts, are being released back into waters. And lake and river projects are reviewed to make sure steps are taken to avoid impacting mussel populations.
Read more in "Several Paths to Build up Mussels," in the June 2010 Wisconsin Natural Resources magazine.
Citizen interest in mussels is increasing. Two years ago, the Citizen Mussel Monitoring Project started and has since trained more than 200 volunteers about the value of Wisconsin freshwater mussels and how to identify them, and many of these people and school groups are documenting what species occur and where they occur in Wisconsin lakes, rivers and streams.
Freshwater mussels are part of a larger group of aquatic animals known as bivalves, for their two external shells. A critical link in their lifecycle is that native mussels must have a host species, usually a fish, to complete their life cycle. Some mussels species use only one type of fish, others use a number of fish species.
Identifying mussels can be tricky. Shell shape, color, size, features such as bumps, ridges and patterns, and beak structure are all used to determine the species. Check DNR's mussels and clams page for links to photos and more information about the different species.
Habits and habitat:
Mussels' life cycle begins with the male mussel expelling sperm into the water. Those cells are taken in through the female's incurrent siphon and the fertilized eggs develop into embryo mussels called glochidia. The female mussel expels glochidia into the water when her young are mature and the right fish species appears. When the fish eats, it swallows the blast of embryo mussels. Once swallowed, the glochidia wind up on the fish's gills and attach themselves there. Within a week to a month, most young mussels are ready to drop off and live on their own. Mussels live to be 20, 30, 40 or more years old and some have been aged over 100 years old.
Mussels bring food in through their incurrent siphon which has little appendages which keep out the big chunks and allow the small stuff to pass. They feed on green algae and diatoms and pass the items they don't eat out their excurrent siphon for other bottom dwelling organisms to consume.
Mussel mothers have evolved elaborate ways to entice fish and increase the probability of attaching glochidia to their hosts' gills. Some release glochidia in clusters in the shape of worms or bugs, others have developed fleshy appendages that mimic fish prey; the Higgins' eye mussel, for example, has a lure that looks like a delectable minnow to tempt its hosts.