Measuring Mississippi mussels
The U.S. Army Corps of Engineers is conducting a mussel survey in the pool at Lock & Dam No. 3 this week and next week.
The survey is in preparation for a pool-wide drawdown, which will take place in the coming years, corps biologist Dan Kelner said. During the drawdown, the pool water level is reduced, allowing some native plants to regrow. However, the reduced water level can put native mussel populations at risk, Kelner said.
"It's very important that we have an idea of the impacts on mussels," Kelner said.
The corps, along with several other state and federal agencies, will conduct 300 quadrat tests over the next several days.
"It's very labor-intensive," Kelner said.
During these tests, divers enter the water and collect all the mussels in a pre-measured area. This test allows the team to determine the mussel density in that area, which they can then use to estimate mussel density in the entire pool.
"We can estimate how many mussels can be exposed (by the drawdown)," Kelner said.
On Tuesday, the corps team collected about 10 species of mussels, including Butterfly, Deertoe and the invasive zebra mussel. They also found several Higgins' Eye mussels, which is a federally endangered species that the corps and Kelner are helping to rehabilitate in the Upper Mississippi.