USFS trying to save native river mussel in Tahoe
Western pearlshell mussels in the Upper Truckee River are being measured, weighed and tagged. Photos/Kathryn Reed
By Kathryn Reed
Part of the U.S. Forest Service’s nearly $5 million restoration of its section of the Upper Truckee River includes relocating 12,000 Western pearlshell mussels.
This summer 10 percent of the mollusks are being plucked from the river’s bottom, weighed, measured and tagged, then put in coolers before being relocated to other sections of the river, as well as Trout Creek, as part of a pilot project.
Scientists want to see how the relocation works before all of the mussels are moved.
Different control plots have been created so if there is a die-off the scientists will ideally be able to isolate what went wrong.
Mason Bindl hovers on the water, splashing a bit as he uses a snorkel and mask to look for these mussels that look big enough to eat. He scoops them into a mesh bag.
On the riverbank are Cody Bear, Phil Meting Van Rijan and Erin Miller. They are recording the particulars about the mussels so as monitoring begins in October, and then continues every three months, officials will know the survival and growth rates.
Working on the project are, clockwise from right, Mason Bindl, Cody Bear, Phil Metting Van Rijan, and Erin Miller.
If they aren’t removed, they all would die. This is because where they are will be drained in 2016 and then filled in with dirt. A final sweep of the current channel will be made that summer to retrieve any stragglers.
A new 7,000-foot river channel has been in the works for a few years.
Sarah Muskopf, fish biologist with the USFS, said, “It’s important to salvage this population. Not only is it the last one, but it’s a huge part of the ecosystem.”
The creatures, which can live to be 100 years old, are considered filter feeders. This means they feed off the nutrients and contaminants in the water, which in turn helps with clarity.
These native mussels used to be prolific in the Upper Truckee Watershed. Their numbers are diminishing. While scientists don’t know exactly why the decline has occurred, they point to declining habitat for the mussels.
“The habitat is marginal here at best,” Muskopf said.
They prefer cold, clean water with a cobble or gravel floor. That’s exactly what is being designed for the new channel.
Most of the current channel lacks gravel, is warming because it is so shallow and is murky because of all the sediment.
River otters are the mussels’ main predator. When the Lahontan cutthroat trout were in the river this also helped the mussel population grow because they would feed off the excrement.
Besides the Upper Truckee River, these pearlshell mussels are found in the lower Truckee River – beyond the dam in Tahoe City – and in other fresh water bodies in the Western United States.