Mussels in the Blue II: Relative Abundance of Species in the Blue
By Craig Thompson
Last week I posted a blog article discussing Mussels in the Blue River, and the work performed by the Kansas Department of Health and Environment (KDHE) and by EPA Region 7 over the last several decades to conduct qualitative mussel surveys. Last weeks blog focused mostly on rare species. This week I will be discussing the relative abundance of species in the Blue River (collection sites are shown below in the Figure 1.).
To record mussel community information, KDHE and EPA used the following – waterbody, location, scientific name, common name, collection date, collectors, relative abundance, shell condition, and width/length measurements. I mentioned last week that there are about 45 species of mussels recorded for the state of Kansas (approximately 69 for Missouri). One of the things I enjoy while collecting mussels is to identify them by their scientific name. With only 45 species of mussels compared to hundreds of species of aquatic insects they are much easier to remember and memorize. One of the most abundant shells found at 159th is from the Asian clam (Corbicula fluminea, Figure 2). Corbicula is a small, non-native clam that was introduced years ago and has since populated most waterbodies of the United States. It has many evenly-spaced concentric ridges on its outer shell, and it has been collected at every site along the Blue. At this time, there are no Zebra mussels (Dreissena polymorpha) in the Blue.
The most common native mussel species found at 159th are the Mapleleaf, Threeridge, Giant floater, Pondmussel, and White heelsplitter (Table 1). These species also appear frequently at other sites along the river. A Mapleleaf (Quadrula quadrula, Figure 3) has a thick shell that is quadrate in shape. It has a line of pustules on the outer part of its shell. When I am sampling any site on the Blue I usually find Mapleleafs together with Threeridge mussels. Threeridge (Amblema plicata) has a thick shell with three horizontal ridges (sometimes more). Giant floater (Pyganodon grandis) is another mussel with an interesting name. If you want to have some fun with the shells, place the shells in the water with the inside part (the pearly interior) facing up and you will see them float down the river. The shell of this mussel is very thin and can break easily in younger specimens. Older specimens can get quite large and up to ten inches in length. Pondmussels (Ligumia subrostrata) are common in small streams and ponds throughout the area. The shell is elongate and smooth with growth lines. You can easily tell the sexes of this species (called sexual dimorphism). Males have a longer shell that is more pointed than females. Female Pondmussels are shorter and more inflated. White heelsplitter (Lasmigona complanata) is a large mussel associated with medium to large rivers and it’s shell is ovate and smooth and the nacre is white. This mussel may have received its common name from people stepping on it barefoot.
One day, and on my own time, I just decided to take a look upstream from 159th. I received permission to get on the river from a piece of property managed by the Kansas Land Trust. In September, I found five different species of mussel shells (Table 2) on a gravel bar, and I also observed several live Mapleleaf and Threeridge mussels in a shallow run. These two species are very common in streams in Kansas. Their thick shells were once used to make buttons but are now used to produce pearls for the cultured pearl industry. Monkeyface and Bleufer mussels are used for this purpose as well, but they are found only in clear flowing streams in southeast Kansas. Another site I explored recently was about a mile downstream from 159th. The site is called “Near a relative’s home”. I was visiting my nieces on their birthday and saw a great opportunity to access the Blue from their backyard. Anyhow, I was more interested in collecting mussels that day than eating cake and ice cream. When I finished my cake, I hurriedly crawled down the banks of the Blue to check for mussels. My young nieces enjoyed the shells I collected from the river. As I recall, I gave them some Mapleleaf shells, which they thought were very cool. Anyway, there was nothing rare or unusual, but it was exciting to find 10 species (Table 2) at this site.
Next week stay tuned for the thrilling third and final installation of Mussels in the Blue, where I will discuss the water quality challenges that face the Blue River.
Craig Thompson lives near the mussel-less (except for Asian clams) Brush Creek, a tributary of the Blue River. He is a Life Scientist with the Environmental Assessment and Monitoring Branch (EAMB). Craig joined EPA in 2009 after spending thirteen years with Kansas Department of Health and Environment. He assists EAMB staff with water quality and biological sampling surveys throughout the Region 7 area.
Editor's Note: The opinions expressed in Greenversations are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.