Where There's a Gill, There's a Way
A new experimental mussel project at Gavins Point National Fish Hatchery could help restore aquatic ecosystems
Is the U.S. Fish and Wildlife Service full of mad scientists? No, but our biologists do conduct experiments to find the best ways to care for our ecosystems.
Biologists at Gavins Point National Fish Hatchery in Yankton, SD in cooperation with Genoa National Fish Hatchery recently began an experimental mussel project that could help restore black sandshell mussel populations and aquatic ecosystems. The crew are investigating whether flathead chubs (a large Missouri River minnow species) will work as a host for black sandshell mussel glochidia (larvae).
Explore today's "Field in 5" to learn more about this experiment and how it could benefit our aquatic ecosystems.
Photo: Black sandshell mussel with visible water tubes by Sam Stukel/USFWS
The glochidia (larvae) of black sandshell mussels are held in structures called water tubes, visible here. Once released, they will seek out a host fish and attach to their gills. The glochidia spend several weeks growing there before swimming free.
Photo: Flushing out the glochidia (larvae) by Sam Stukel/USFWS
Biologists have to flush the glochidia (larvae) out from the mussels' water tubes before they can be exposed to the flathead chubs.
Photo: Biologist taking a closer look at the glochidia (larvae) by Sam Stukel/USFWS
Before introducing them to the host fish the biologists take a closer look at the glochidia (larvae). Not every fish species works as a host fish for mussel glochidia. We are curious about flathead chubs, which are common in some local Missouri River tributaries. It is likely these fish once shared habitat with the black sandshell mussel in Nebraska - a place where populations of this mussel species have been destroyed.
Photo: Biologists inspecting the gills of a flathead chub by Sam Stukel/USFWS
The crew inspects the gills of a flathead chub after it is exposed to the glochidia. The fish are not typically affected by hosting mussel glochidia. There may be some scarring to the gill tissue but unless they host an exceptionally large number of glochidia it is not enough to negatively affect respiration. Mussels get a big benefit from the fish because they help disperse the glochidia throughout the river or lake.
Photo: Biologists check buckets with flathead chubs at Gavins Point National Fish Hatchery by Sam Stukel/USFWS
The exposed flathead chubs are spread out among a set of buckets. In a couple weeks the biologists will carefully check to see how many glochidia developed into the next stage. This experiment may eventually lead to a restoration program for the black sandshell mussel in Nebraska.
Why are mussels so important?
Mussels provide many benefits to aquatic ecosystems. Mussels serve as a living filter system for our rivers and lakes. Since they are extremely sensitive to chemicals and metals, mussels can also be a water quality indicator. Mussel beds provide habitat for numerous invertebrate species and fish and adult mussels are a food source for birds and mammals.
Why is this experiment important?
Many species of mussels are threatened or endangered in the Midwest due to water quality issues and changes to aquatic habitats. Dams and channelization affect habitat which (among other things) reduces the prevalence of some host fish species. Sedimentation covers up sand/gravel beds and smothers mussels. Toxic pollutants are very hard on filter feeders and invasive species like zebra mussels offer heavy competition.
Experiments like this one at Gavins Point National Fish Hatchery, could help restore populations of mussels that were once a prominent part of aquatic ecosystems in this region.
Connect with Gavins Point National Fish Hatchery on Facebook to stay updated about the progress of this experiment!
