Mussels in the Blue
By Craig Thompson
For the last four years I have been sampling wadeable streams throughout the metropolitan Kansas City area. I am part of the water monitoring team within the Environmental Assessment and Monitoring Branch (EAMB) at EPA Region 7. I grew up in Mission, Kansas. I was always outdoors exploring the woods behind my parents house and wading the waters of Turkey creek and other creeks in my neighborhood. Now, I am responsible for collecting water and biological samples from some of these same creeks. My particular area of expertise is macroinvertebrate sampling (freshwater mussels and aquatic insects). I am fascinated with the mussel community information that has been collected from several sample sites on the Blue River (Figure 1).
During the 1991-2011 sampling seasons, qualitative mussel surveys were conducted on the Blue River by Kansas Department of Health and Environment (KDHE) and by EPA Region 7. The upper Blue River supports a diverse community of mussels compared to the lower Blue River. The Blue River at 159th Street and Kenneth Road has one of the most diverse mussel communities of any urban stream site in the metropolitan area (Table 1).
There are approximately 45 species of mussels found in Kansas. Kansas Department of Wildlife, Parks and Tourism (KDWPT) lists 6 endangered and 5 threatened species. In addition, they have a category called “species in need of conservation”, or SINC species. There are at least 17 species of mussels found in the Blue River. The site at 159th has one endangered and four SINC mussel species. The Mucket is an endangered mussel found typically in the Marias des Cygnes river basin (several miles south of 159th). This rare mussel is outside its normal range, but it may have occurred in the Blue River (Missouri River Basin) historically. The Creeper, Fatmucket, Wabash pigtoe and Yellow sandshell have interesting names and are SINC species. Creeper (formerly called Squawfoot) is a rare find for this river and only one shell was collected at 159th.
Fatmucket is an unusual name for a mussel. The “fat” part of this mussel’s name probably came from describing the swollen shape of the shell of this species. This characteristic is very common in older individuals and in females. This mussel is doing fair at 159th with a few weathered shells found at other sample sites along the river. Wabash pigtoe and other freshwater mussels are recognized by the shape of their shell. They have either animal hoof or foot characteristics. Names like Fawnsfoot, Round pigtoe, Deertoe, Elktoe and Rabbitsfoot are some of the species in this group. Wabash pigtoe is also doing fair at 159th with some recent and weathered shells found at other sample sites. The Yellow sandshell is a beautiful mussel. The outer layer of the shell (called periostracum) is a distinct yellow and the nacre (the iridescent, inner layer) is silvery-white (Figure 2). The Yellow sandshell is doing well at 159th with some recent shells (unweathered shells) found in 2011. Also, a few recent shells have been collected at other downstream sites.
The other rare mussels identified in the survey may possibly be extirpated (locally extinct) from the Blue River basin. The Pimpleback is common in other streams in the state but is rare in the Blue. It has numerous raised structures on the outer part of its shell called pustules. I have not observed this species for a long time and the last time shells were collected was in 2005. The Pistolgrip is an easy mussel to identify (general shape of a pistolgrip). It is a thick-shelled mussel that is elongate with distinct knobby ridges and pustules. The last time it was discovered at 159th was in 1993. The Plain pocketbook shell is oval and large. It is usually present at 159th and other sites along the Blue but not in high numbers. And, the shell condition is usually weathered or relict. Finally, the Lilliput is a mussel that is hard to find because of its bean-shaped size. Some shells measure around an inch in length and only a few have been collected at 159th.
Next week, I will discuss the relative abundance of species found in the Blue as well as some of the main water quality problems facing mussels in the Blue.
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 here 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.
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