Tuesday, April 28, 2015

Washington State Turns to Neurotoxins to Save Its Oysters

What could go wrong?

Six decades ago, when Dick Sheldon first got into the oyster business, the tide flats of Washington states Willapa Bay were almost free of blight. There were no crabs (well, almost none) and Sheldon used to hike onto the mud at low tide, with a bucket for oysters. “We’d walk a mile or more, even when it was freezing outside, with the wind blowing at 50 miles an hour,” he remembers wistfully, “and then we’d stoop to the mud and start gathering them and throwing them into the buckets.”

In Sheldon’s memory, the oysters were bountiful and the mud floor was firm and pleasant to walk on. Then the shrimp arrived, and everything changed. Burrowing shrimp dig holes in the mud and live there. They pock the tide flats with a zillion holes, and today Sheldon, the 80-year-old eminence grise at his family’s small Northern Oyster Co., considers Willapa Bay a vanished world floored by “quicksand. If you’re not careful out there,” he says, “you’re up to your waist in that shit.”

The shrimp began proliferating—mysteriously, like a plague of locusts—in the early 1960s. They dominated the bay floor where oysters lived, but back then there was a simple solution: The oystermen just bombed the shrimp with carbaryl, a DDT-era neurotoxin. The shrimp, which few humans would want to eat, died. Oyster harvests were good, and along the bay, in towns like Nahcotta and South Bend and Oysterville, eight now-defunct oyster canneries flourished.

By the early 2000s, though, carbaryl had become a legal liability. Numerous researchers have linked the chemical to cancer, and in 2002 environmentalists strong-armed the Willapa/Grays Harbor Oyster Growers Association (WGHOGA) into beginning a 10-year phaseout.

A way of life and a small corner of the world were suddenly in jeopardy. Willapa Bay produces more cultured oysters than any other bay in the U.S., yielding about $35 million a year in product. The oyster industry forms the economic backbone of Pacific County, pop. 20,000, where road signs celebrate “The Oyster Capital of the World.” But in 2002, oystermen were scrambling to figure out a new way to kill off shrimp—and they found just the scientist to help them.

Kim Patten, an agricultural extension specialist for Washington State University (WSU), tried blasting the shrimp to bits with dynamite. He did not succeed. He turned his sights next on hitting the shrimp with “a very thin layer of sprayable concrete,” he says, “just an eighth of an inch, so they’d suffocate.” No luck. “By the time the concrete firmed up,” Patten says, recounting a test run, “the shrimp had already poked holes through it.”

Patten, who was trained as a horticulturalist, tried electrocution, super-spicy habanero peppers, and mustard gas. The shrimp held their ground. At last he turned to a newer neurotoxin, imidacloprid, which temporarily paralyzes the shrimp, so that they stop digging and within two days suffocate in the mud.

Imidacloprid is the world’s most popular pesticide, and highly controversial. It belongs to a family of neurotoxins, neonicotinoids, that is increasingly being blamed for colony collapse disorder—the sharp die-off of honeybees that has plagued North America since 2006. The U.S. Fish and Wildlife Service, the National Marine Fisheries Service, the National Audubon Society, and the Xerces Society, which advocates for invertebrates, have all opposed the chemical’s use on Willapa Bay. But their protests are now moot. On April 16, the Washington Department of Ecology approved the spraying of imidacloprid on 1,500 acres of Willapa Bay and 500 acres of nearby Grays Harbor. In about a month, crop-dusting helicopters will begin dousing both estuaries with the chemical.

Unlike carbaryl, imidacloprid dissolves in water, meaning that fish will swim through trace quantities of the chemical and oysters will grow in an imidacloprid-laced bay. It will be a first: Imidacloprid has never been applied on water before in the U.S.

by Bill Donahue, Bloomberg Business | Read more:
Image: Cameron Karsten Photography