Update: Endangered Mussels Return to Wild

by kespeland on January 14, 2010

In April 2008, two biologists, including Kentucky Fish and Wildlife biologist Monte McGregor, donned waders and masks and trudged into some familiar territory.  Here’s a scene from that story:

They’re combing a section of stream in the upper Cumberland river system for an endangered mussel species called the Cumberland Bean. It’s a black, bean-shaped mussel that could easily fit in the center of the palm of your hand. They’re trying to find pregnant….or gravid in the mollusk world…females.  And they’re finding anything but.

“I’ve got four females of the Painted Creek Shell and four females of the Rainbow mussels that are gravid that I’ll be taking back and doing some work with them as well.”

McGregor kneels near the bank, sorting through a small pile of mussels the two have found. Some he’ll take back to his lab and others he’ll replant in the stream.  Last year, they tagged Cumberland Bean females with a little magnetic sticker and plopped them back in the water.  Today they’ve come back with a kind of aquatic metal detector to try to pick up their signals.  But the search has turned up little.

“It’s not good seeing all the dead animals here. That’s kind of alarming.  We’re not sure why they’re dying.  Again, they’re very sensitive animals.’”

Tanks of homegrown algae, in various stages of development

But on a recent trip back to McGregor’s new mussel nursery—which is a big greenhouse full of gurgling tanks of algae and tubs full of dozens of shapes and sizes of mussels—the news is better.

“You see all this mussels?  These are the ones we’ve raised.  There’s three or four endangered species in here.  This one on top is the Cumberland Bean,” says McGregor.

It’s not easy to find an endangered mussel species in the wild.  But McGregor says that after a few more return trips to the stream, he finally found some pregnant Cumberland Beans—exactly what he needed to nurture a new mussel family in the safety of his lab.

A juvenile Cumberland Bean mussel, raised in the lab

“And we were able to raise some juveniles.  We’ve already released those this year, we released 40 something. And they were very large-sized.  They’re going to survive.”

McGregor says it’s like introducing a whole new class of first graders—rather than just a student or two–to a school who will go on to graduate together.

“So this is what we’re doing basically in the mussel community, is we’re adding a bunch of first graders, a bunch of babies, to the population that would normally take 40 or 50 years to get that many.”

That’s because McGregor has perfected the technique of raising mussels in a controlled environment.  It’s meant everything from extracting the microscopic larvae from pregnant mothers to developing just the right mixture of algae and river water to sustain them.

Tubs of growing mussels, fed by river water that circulates through native plant roots

“You know I’ve worked 12 years trying to figure out how to do this. And so in the last couple, three years, we finally, we’ve got a formula that works.  And we’re being able to see the fruit of that with several species and several rare species.”

Why spend so many years on a creature people rarely think about, let alone see?  McGregor says that mussels are a sentinel species, a sign of the health of an ecosystem.  Under healthy conditions, they filter millions of gallons of water as they feed and make a tasty meal for other wildlife.  But they’re sensitive creatures.  And so long-term pollution and changes to their habitat have made them one of the most federally endangered in the nation.  Another Kentucky native species,

A rabbitsfoot mussel, now a candidate for the Endangered Species list

the rabbitsfoot mussel, was just proposed for listing last month.

About a year and a half ago, we brought you the story of Kentucky’s endangered mussels, and the struggle to save them.  Decades of pollution and habitat loss have put a large percentage of our watershed’s freshwater mussels on the federal endangered species list.  Now, WFPL’s Kristin Espeland Gourlay has this update on one mussel – with a little good news.

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