FORT LARAMIE – The population of Goshen Country grew by about 1,000 recently.

It wasn’t a sudden influx of refugees fleeing natural disaster and there wasn’t a baby-boom. 

Instead, a Wyoming Game and Fish Department crew was at Fort Laramie National Historic Site in the western reaches of Goshen County with a project to reintroduce a once-predominant species of freshwater mussel back into its former home.

The species goes by the somewhat unassuming name of the plain pocketbook mussel and its overall appearance somewhat matches its moniker, with a tan shell and green stripes a predominant feature. But what they did – and can do – for the rivers outweighs its humble visage. 

“They’re kind of nicknamed the livers of the rivers,” said Stephen Siddon, the WGF Fisheries Biologist based in Laramie who conceived of the reintroduction project.

“They’re constantly filtering the water, removing organic [contaminants], even some bad stuff we don’t like, like e. coli and algae out of the water. They help to clean the rivers,” he said. “They’re good for water quality and they’re also food for other critters – otters, mink, raccoons, you name it.

“They’re pretty important to have around.”

The plain pocketbook mussel was once found up and down the Laramie and Platte rivers in Wyoming, well beyond the reaches of Fort Laramie NHS, Siddon said. Historically, they were a staple of life for the indigenous peoples who called the area home. Shells have been found in excavated middens, or refuse piles, discovered during archeological digs. 

He had no hard evidence, but Siddon believes the meat of the mussels were a possible food source and the shiny inner shell could have been used for a variety of applications, from decoration to trade.

In addition to the FLNHS site, another about 1,000 mussels of different ages were reintroduced at a Laramie River site upstream of the Grayrocks Reservoir. That site is near the last location a live plain pocketbook mussel was reportedly identified, in 2008.

“We’ve been looking for the last 15 years,” Siddon said. “They used to be here, and they used to be here in pretty good numbers. We find the shells everywhere.

“They’re important for our rivers and we wanted to bring them back because they’re filter feeders,” he said. “We chose to reintroduce them because we find their shells throughout the Laramie River and clear up the North Platte River from a population that used to be here.”

The mussels introduced last week were provided by the Nebraska Game and Parks Commission, which Siddon said is wrapping up a long-term project to reintroduce the plain pocketbook on stretches of the Platte River in that state. Mussels in three age groups – one year, two years and three years old – were interspersed along the bottom of several locations in the Laramie River from populations grown for that Nebraska project, giving them a better chance to adapt and flourish in their new home on approximately three linear miles of river at the historic site, he said.

Chris Mathers, cultural resource manager at FLNHS, assisted with the project, getting paperwork for grants and permissions through the pipeline. He also rolled up his pantlegs, waded into the slow-moving water and placed mussels in their new homes.

“Historically, these mussels were native in the waterways of this drainage,” Mathers said. The plain pocketbook mussel “has been identified by Game and Fish as a species of greatest conservation need. They are appropriate to this location.”

The project was funded primarily by Wyoming Game and Fish with the mussels provided by its counterpart in Nebraska. Siddon said, ideally, he will follow up, placing more mussels at locations along the river at least a couple more years. That further increases the chances of success, he said. 

“I don’t think the population will ever return to historic levels – we wouldn’t even know if it did,” Siddon said. “And we’ll never have the complete data to be able to examine the exact changes in the water quality because of these mussels. But it’s just one more component we can add to help restore the rivers.”