Scientists seeking cause of huge freshwater mussel die-off

A pile of recently dead freshwater mussels are piled along the shore of the Clinch River near Wallen Bend, Tennessee. (AP)
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Updated 17 December 2019

Scientists seeking cause of huge freshwater mussel die-off

  • Freshwater mussels range from about the size of a large button to the size of a billfold
  • Mussels benefit the people who use their rivers as a source of drinking water

KYLES FORD, Tennessee: On a recent late fall afternoon at Kyles Ford, the white branches of sycamore trees overhung the banks of the Clinch River, leaves slowly turning yellow. Green walnuts covered the ground.

The shallow water ran fast and cold over the rocky bottom, but it was littered with the white shells of dead mussels.

Freshwater mussels range from about the size of a large button to the size of a billfold, but the work they do for ecosystems is enormous. They can filter around 8-10 gallons of river water each day, cleaning it of algae, silt and even heavy metals and making the whole river a better environment for fish, amphibians, plants and bugs. Mussels also benefit the people who use their rivers as a source of drinking water.

That’s why scientists are working quickly to discover the cause of a massive mussel die-off on the Clinch and understand whether it is related to similar die-offs on at least five US rivers and another in Spain.

The Clinch River, winding 300 miles through Appalachia, is home to 133 species of fish and is one of the most important rivers for freshwater mussels in the world, with 46 different species — more than in all of Europe.

“I always try to get people to call this area a temperate Amazon, because the biodiversity here really is off the charts,” biologist Jordan Richard, with the US Fish and Wildlife Service, said recently as he stood in waders, surveying the mussel population at Kyles Ford, a rural community of around 525 near the Virginia border.

Richard slogged through thigh-deep water in search of pheasantshell mussels, until recently one of the most abundant species on the river. He spots them easily although to the untrained eye, they aren’t so obvious. Mussels bury themselves in the riverbed, digging in with their single foot and leaving only a crescent of their shells visible.

In 2016, Richard noticed the pheasantshells were dying in large numbers — the population dropping from 94,000 in 2016 to less than 14,000 this year on a 200-meter (219-yard) stretch. He estimates hundreds of thousands, possibly millions, have died in the larger river.

Richard found reports of similar die-offs over the years in rivers around the world, but he didn’t find many answers.

Over the past century, mussel populations everywhere have declined steeply due to pollution, habitat loss and climate change, yet the current decline looks to be something different.

Richard and a team of scientists suspect an infectious disease. By comparing healthy pheasantshell mussels with dying ones, the team is narrowing down a list of suspected pathogens.

“All living things are chock-full of microorganisms, and we don’t have any sort of map for what is healthy inside a mussel,” Richard said.
University of Wisconsin epidemiologist Tony Goldberg is helping with the investigation. He specializes in wildlife diseases of unknown cause — and recently he’s been busy.

“Along with invasive species, we’re seeing invasive pathogens,” Goldberg said. “Often it’s the coup de grace for a species that is holding on by a thread.”
Disease is a big part of the global extinction crisis, he said. For example, white nose syndrome was first discovered in a single New York cave in 2007 and has since killed millions of bats, and chytrid fungus is responsible for the demise of tree frogs and about 200 other amphibian species worldwide.

But Goldberg is hopeful the freshwater mussel team, which includes scientists from the US Geological Survey and a nonprofit conservation group, will be able to find the cause of the mussel die-offs and a way to stop them.

“I see it as a race against time, not an impossible task,” Goldberg said. “We’re all motivated by the sinking realization that if we lose these mussels, the rivers we all love are never going to be the same.”

The Clinch, which is relatively pristine on its upper reaches, has seen 10 mussel species go extinct — it used to have 56. Another 20 species there are endangered, including mussels with evocative names such as fluted kidneyshell, snuffbox, birdwing pearlymussel, and shiny pigtoe.

Preliminary results indicate that whatever is killing the pheasantshell mussels on the Clinch is not the culprit in other die-offs under investigation in Wisconsin, Michigan, the Pacific Northwest and Spain.

“There’s not some mussel Ebola sweeping across the world to take out every mussel everywhere,” Goldberg said.

That also means there’s no single cure for what’s killing them.

In Spain, biologist Rafael Araujo is working with Goldberg to figure out what is killing the last of the endangered Spengler’s freshwater mussels in the Imperial Canal on the Ebro River.

“We know that the problem is environmental (dams, water pollution, excess fertilizers, pesticides, exotic species, lack of water, etc.), but we also think that there could be a pathogen (bacteria and/or virus) that is making things worse,” Araujo wrote in an email.

In Oregon and Washington, Emilie Blevins is studying the die-off of western pearlshell mussels in her role as a biologist with the Xeres Society for Invertebrate Conservation.

Blevins likens mussel beds to coral reefs in terms of their diversity and contributions to other aquatic life. But she acknowledges, “They just don’t get the spotlight of some other big, beautiful species. A big part of all of our work is ... spotlighting how important they are because if we don’t value them, they’re not going to be around.”


US to pay over $1bn for 100m doses of J&J’s potential COVID-19 vaccine

Updated 3 min 37 sec ago

US to pay over $1bn for 100m doses of J&J’s potential COVID-19 vaccine

  • The latest contract equates to roughly $10 per vaccine dose produced by J&J
  • This is J&J’s first deal to supply its investigational vaccine to a country

WASHINGTON: The United States government will pay Johnson & Johnson over $1 billion for 100 million doses of its potential coronavirus vaccine, its latest such arrangement as the race to tame the pandemic intensifies, the drugmaker said on Wednesday.
It said it would deliver the vaccine to the Biomedical Advanced Research and Development Authority (BARDA) on a not-for-profit basis to be used after approval or emergency use authorization by the US Food and Drug Administration (FDA).
J&J has already received $1 billion in funding from the US government — BARDA agreed in March to provide that money for the company to build manufacturing capacity for more than 1 billion doses of the experimental vaccine.
The latest contract equates to roughly $10 per vaccine dose produced by J&J. Including the first $1 billion deal with the USgovernment, the price would be slightly higher than the $19.50 per dose that the United States is paying for the vaccine being developed by Pfizer Inc. and German biotech BioNTech SE.
The US government may also purchase an additional 200 million doses under a subsequent agreement. J&J did not disclose that deal’s value.
J&J plans to study a one- or two-dose regimen of the vaccine in parallel later this year. A single-shot regimen could allow more people to be vaccinated with the same number of doses and would sidestep issues around getting people to come back for their second dose.
This is J&J’s first deal to supply its investigational vaccine to a country. Talks are underway with the European Union, but no deal has yet been reached.
J&J’s investigational vaccine is currently being tested on healthy volunteers in the United States and Belgium in an early-stage study.
There are currently no approved vaccines for COVID-19. More than 20 are in clinical trials.