Thornwood’s healthy creek is mussels’ home

HANCOCK COUNTY — One of the ways to tell a healthy creek is to observe the mussels that may be there. Now, thanks to the Indiana Department of Natural Resources, we have the answer for the creek that runs through Thornwood Preserve.

We had a great and successful morning wading in the Little Brandywine from one edge of the property to the other. A couple of the pools were a bit deep on me, but I can swim.

There are 71 species of mussels that can be found in Indiana; some are widespread, and some are located mostly along the Ohio River. There are 38 species that are widespread enough within the state to be found in our area.

Located within the Little Brandywine, we were able to find six native freshwater mussels. The creek also happens to be home to an invasive species, the Asian Clam, but it hasn’t gotten to be a problem yet.

The ones we found were all dead — shells only — but it also means that they are there and we just didn’t find any live ones (we also found a snapping turtle, but that’s another story).

Now, for a little note on mussel anatomy for those interested. Mussels have two sets of teeth, the lateral and the pseudocardinal, and they also have a beak. These are important to know if you need to identify a particular mussel. Mussels come in two parts known as valves, the right and left. They also come in male and female, which is really important if you’re a mussel, and they do differ slightly in shape.

The six we found in the creek are pretty common for Indiana.

Plain Pocketbook (AKA Grandmaw); these shells are round or squarish and are generally yellow or tan color sometimes with green rays. They can get up to seven inches. These are widespread and common in Indiana.

Fatmucket (AKA Grass Mucket, Pugnose Mucket); these shells are more elongated with a thick yellow or tan shell or sometimes brown. These tend to get about five inches long. These are widespread and common throughout Indiana.

Little Spectaclecase (AKA Black Creek Shell); these are small and a bit elongated, only getting to about two-and-a-half inches long. The shell is a dark brown. These are widespread but uncommon and a species of special concern in Indiana and is endangered in Illinois and Ohio.

Lilliput; these are very small, usually no longer than one inch, dark green or brown with a cylindrical shell. These are widespread in Indiana.

Giant Floater (AKA Floater, Hogshell and Slopbucket); this one is our largest mussel. It has an elongated shell that is smooth and light yellow or yellowish green. It can get up to 10 inches. It’s also only one we have that doesn’t have teeth. A very common mussel throughout Indiana.

Spike (AKA Lady Finger); this one has a thick elongated shell and generally greenish brown or black. This one may get up to five inches.

Now, on to the invasive Asian Clam (Corbicula fluminea). This species was introduced (or first found) in 1938 in Washington State. It has spread to 44 states as of this year. How it got here is not known; it may have come in as a food source, as it’s edible, or some other method. The problem with these is that they reproduce in large colonies that can clog waterways and pipes. They also increase a type of algae that can be a skin irritant to humans and animals.

This clam is relatively small with a yellowish brown to black shell with numerous ridges. The shell is rounded to slightly triangular. If you happen to find any of these feel free to toss them out of the water or you can collect enough to make a soup.

Next time we’ll talk about all the fishes that live in the Little Brandywine.

SPECIAL NOTE: It is illegal to remove any native mussel, dead or alive, from any Indiana body of water.