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Saving the Paddlefish - 2002-08-17

Long before dinosaurs roamed the earth, a fish swam the large rivers of what would become known as North America. The only living species of its kind, paddlefish have remained virtually unchanged for millions of years. Not only are they an ecological artifact, they are prized for their flavor and caviar, which has led to sharp declines in their population. The U.S. Fish and Wildlife Service has started a project to restore paddlefish to major American rivers. Erika Celeste takes us to Parkersburg, West Virginia, where the project is underway.

Agent Chris O'Bara quietly steals out onto the river for a closer look. Silence is of the utmost importance on this critical, life-saving mission. The objects of his search hold a key to the mysteries of how life arose on earth. But their dwindling numbers place them in great danger. Without his help, they could be wiped out, forever. The problem now is that they won't come willingly perhaps because they're not sure whose side he's on.

But Agent O'Bara isn't offended. As a biologist with the West Virginia Department of Natural Resources, he finds that most of the animal populations he tries to help would rather not participate. The paddlefish he's trying to tag are no different. "This is a state or national treasure, paddlefish," he says. "It's part of our heritage. It's part of our legacy. Especially on these large rivers, it's something that was there, and due to insults of the past, they have been lost. But with improvements to the river now, we can start reintroducing these species."

Besides belonging to a species that's 300 million years old, that's 50 million years before dinosaurs, paddlefish have several unique features. The bluish-gray creatures have skin instead of scales. On thriving rivers like the Mississippi, they can grow to over two meters long and weigh more than 90 kilograms. However most paddlefish on the Kanawha and Ohio Rivers reach only half that size. Their skeletons are made of cartilage, which led scientists two centuries ago to mistakenly categorize them as a new breed of shark.

"They get their name paddlefish, because they have quite a large paddle off their nose," says Mr. O'Bara. "It would extend out about [46 centimeters] to [61 centimeters]. They actually use it to try and push water through their gills. They are quite unique looking."

The fish's unusual appearance has led to several nicknames, including the freshwater whale, spoonbill sturgeon, and bull-moose catfish. Bret Preston, who manages warm water fisheries for West Virginia's Department of Natural Resources, says preserving these fish would have important environmental benefits: they act as natural garbage collectors. "They live off the main stem of the river and they are filter feeders," he says. "So they also provide an important ecological function as filter feeders removing small plants and planktonic plants and animals in the river as they feed."

West Virginia's paddlefish preservation project runs jointly with the U.S. Fish and Wildlife Service, and was started about ten years ago. Agent Chris O'Bara says the project has ambitious goals. "Our ultimate goal would be to have a sport fishery when the populations reach a level where they can sustain some type of fishing," he says. "Right now our goal is to have populations in the river so that they would function as an ecological component in the river and provide the things they have for thousands and millions of years."

Experts say many factors contributed to the declining population of paddlefish, including the construction of dams, and pollution from riverside plants. But Mr. Preston says that perhaps the single greatest factor working against paddlefish is that they taste so good.

Their firm, white meat is often smoke-cured. Its texture and taste are similar to swordfish or salmon. But that's not all… "One of the main commercial interests in paddlefish is for their caviar. Because of the decline in the sturgeon populations and the availability of sturgeon caviar, paddlefish roe are considered caviar quality. There's been a lot of interest in fishing for paddlefish and using them for production," he says.

While some areas on the Mississippi and Missouri Rivers do allow paddlefish snagging, many states, including Alabama, Tennessee, and West Virginia, prohibit it. "It is illegal to catch and possess paddlefish in West Virginia right now. It was done several years ago because of the low numbers, and that still is a regulation. If you catch one you have to release it immediately."

To help rebuild the paddlefish population, Chris O'Bara and colleagues at the Department of Natural Resources catch mature paddlefish and breed them at a West Virginia hatchery. But that's not as easy as it sounds. Female paddlefish have to be at least 10 years old before they'll spawn. After that, spawning occurs only once every four to seven years. When a female is ready she'll lay about 300,000 eggs on a flooded gravel area. Only a small percentage of the hatchlings survive.

"We raise the little ones up to [38.1 centimeters] or so and then we restock them back into the Ohio and Kanawha River," says Mr. O'Bara. "This year, for instance, we've had an excellent year producing paddlefish. We've already stocked over 1000 fish into the Kanawha River. These were about [30.48 centimeters] fish. We hope to stock another 5000 over the next three months."

In the wild, paddlefish spawning is a long-distance affair. In one month, they can travel 322 kilometers upriver over a 30-day period. With all the modern additions to the rivers, that can sometimes pose a problem for paddlefish. But Mr. O'Bara says the fish are getting smarter. "What we have seen especially on the lower Ohio River is the fish will move through the locks and dams, or when the river's in flood stage, they'll move over the dam."

While part of the paddlefish project is about re-stocking, the other part of the project deals with evaluation. 2002 has been an especially encouraging year, because it's the first time they've found fish from past stockings.

"We actually do tag the fish," says Mr. O'Bara. "There's a minute piece of coded wire put in their snout. We can use a wand similar to what you find at an airport when you go through a metal detector and we can detect that. We also tag the fish with a tag similar to what they put on birds, in the jaw of the fish."

During the evaluation, caught fish are weighed, measured and counted, then released. "We've been doing surveys of the river for about five years now. On any given year we collect about 50-60 fish. Earlier on we weren't collecting as many, but the past couple of years we're starting to collect a few more," he says.

Bret Preston says finding more fish is a rewarding experience, because it means he's doing his job right. "There's a fundamental need to know that things are doing pretty well out there, and the paddlefish is an indicator of how well things are doing. If we can restore those populations, we'll all be the better for it," he says.

That sounds like a mission Agent O'Bara and the paddlefish can agree on.