IMAGES:  The first image shows a broken-rays mussel (Lampsilis reeveiana) with its fish lure.  The actual prey species it mimics is shown in the image as well.  The middle image shows a tiny juvenile mussel (tiny juvenile mussels are often called spat, as are other juvenile bivalve species such as oysters and scallops, but the tiny juvenile mussels released by female freshwater mussels that attach to a host are called glochidia) attached to the gill of its host.  The last image illustrates the destruction caused by zebra mussels.  These zebra mussels are attached to a native freshwater mussel species.  Invasive species such as the zebra mussel can have damaging impacts on native ecosystems and species.

BLANK
Freshwater mussels or freshwater clams are some of the most fascinating aquatic creatures.  They are typically found in freshwater streams and rivers throughout the United States. However, these creeks, rivers, and streams—particularly those associated with mountains—are some of the most sensitive ecosystems, and the aquatic creatures inhabiting these environments depend on clean, clear, and oxygenated water. As a result, many species inhabiting these clear waters, including freshwater mussels, are considered canaries in the coal mine or indicator species.  The condition of these mussels—good or bad—reflects the health of the aquatic ecosystem they inhabit.

As a result of human activities, many species of freshwater mussels are endangered or threatened with extinction. Threats include “dams and impoundment, channelization and dredging, pollution, sedimentation, fish kills that eliminate potential host fish, and introduction of non-native species.”

Invasive species such as zebra mussels are of a special concern, because zebra mussels aggressively take over habitat needed for native mussels.  Zebra mussels will even attach themselves to native mussel species or other aquatic creatures such as crayfish.

It is important to protect freshwater mussels, because they are essential to the health of aquatic ecosystems, since they act as natural filtration systems.  Imagine the cumulative effect of thousands of mussels constantly siphoning particulates from the water column.

Conservation measures such as building public awareness, listing some species as endangered or threatened, and supplementing depleted mussel populations via captive breeding programs are happening.  However, some species of freshwater mussel are difficult to reproduce in captivity, because of their peculiar reproductive cycle.

Freshwater mussels use specially modified tissue to mimic a certain species of baitfish, which is the favorite prey of their targeted host.  The female mussel flaps this specially modified tissue in the current to attract fish.  Once an attracted fish nibbles the tissue, minute juvenile mussels or glochidia are simultaneously released into the water column, and the lucky juvenile mussels attach themselves to the gills of their host fish.  After a period of time—depending on the water temperature—the mussels, having been nourished with oxygen and nutrients by attaching to the fish’s gills, fall off onto the substrate.  Some species of freshwater mussel are difficult to reproduce in captivity, because some species seem to be particular to a certain species of fish.  Subsequently, the correct host species needed to reproduce some freshwater mussels is unknown.

VIDEO: Endangered Mussels

POSTER: Life Cycle of the Freshwater Mussel

POSTER: The Zebra Mussel

On the Net:
Freshwater Mussels of the Upper Mississippi River System

See more Weird And Fascinating Creatures

Image information:

1. The image showing a broken-rays mussel (Lampsilis reeveiana) with its fish lure is by Chris Barnhart, and the image was found here.
2. the image showing a freshwater mussel attached to a host’s gill is by Roger Gordon of the U.S. Fish & Wildlife Service, and the image was found here.
3. The image of zebra mussels covering a native species of mussel known as the fat mucket (Lampsilis siliquoidea) is by the Minnesota Department of Natural Resources, and the image was found here.
4. The poster showing the life cycle of the freshwater mussel was found here.
5. The zebra mussel poster was found here.

:: :: :: :: :: :: :: :: :: :: ::