Wed October 26, 2011
The Strange Life, Death and Reproductive Cycle of an Endangered Mussel
Tigers, grizzly bears, sea turtles and humpback whales have long been mascots of endangered species. But then…there's the pink mucket, which once peppered river bottoms in Kentucky, but has been decimated by pollution.
Earlier this week, a team of scientists ventured into the Green River in an effort to reintroduce lab-grown pink muckets into their natural habitat.
“You better not get on my right side!” Monte McGregor warns. He’s wearing a snorkel, preparing to go underwater. “Stand on this side because as soon as I blow my snorkel, you’ll be in the direct path of my water.”
Every time he comes up, McGregor's colleagues hand him four baby mussels to push into the river bed. The mussels are tiny…a little bit smaller than a penny.
“These animals today that we’re releasing, the pink mucket—Lampsilis abrupta is the scientific name—are just as rare as things you see at the Louisville Zoo or out in the wild in Africa,” McGregor says. But he’s trying to change that.
McGregor is an aquatic scientist with the Kentucky Department of Fish and Wildlife and he works in one of the nation’s few mussel hatcheries. With his staff, he raises endangered species in the lab and then releases them into healthy waterways.
Nobody's going to put the pink mucket on a bumper sticker as a call to action for the environment—it’s not nearly photogenic enough—but what McGregor's doing is restoring an essential part of the river ecosystem.
The mussels act as filters, consuming bacteria and cleaning the water. McGregor says these bivalves are a good barometer of a river's general health.
“These animals are probably the most sensitive animals that live in the rivers and streams today,” he said. “They’re similar to a canary in a coal mine. So if the canary dies, there’s no oxygen. Same thing in the river. If these mussels are dying off, then something’s going on in the water that’s causing that water not to be clean anymore.”
Besides killing mussels, pollution also wreaks havoc on their sex lives. Okay…so the muckets don't exactly have sex, but their reproduction is a team sport.
It takes bass—as in the fish—to make more muckets. When a female mucket is fertilized, she incubates the fetuses in her shell. Then she puts out a lure especially designed to attract bass. When the fish bites, she releases the fetuses. They stay on the bass for weeks, then drop off and live alone.
“It’s not easily done. There’s a lot of chances for that chain of events to break down,” says Leroy Koch, a scientist with the U.S. Department of Fish and Wildlife.
“All they really need to do is replace themselves throughout their lifetime to keep their population stable,” Koch said. “But I think often they’re not even able to do that. So the immense numbers that females produce and that process, it’s not real conducive to a quick population growth.”
By growing them in a hatchery and releasing them into the river, Koch and McGregor hope to give the muckets a fighting chance in their natural habitat. The Green River has started to recover from years of pollution and now a single 10-mile stretch contains about 16 percent of all the species in the country.
Monte McGregor is in the river, too, exhilarated by his several minutes in the fifty-degree water.
Koch looks on.
“It’s taken us a long time to get to this point,” he said. “It’s taken many years, many decades, to lose the mussel resource. It’s going to take a while to recover. It’s because of the condition of our streams. Everything that we put on the property, on the land, flows downstream. For mussels, it’s pretty remarkable that we have as many left as we do.”
And the scientists are hopeful. They’ve tagged all the mussels, and they’ll be back in a year to check on them.