Smugglers keep hauling live Asian carp from Southern fish farms bound for food markets in the Lake Ontario city of Toronto, even as the U.S. Army Corps of Engineers studies how to keep the fish from swimming into the Great Lakes through the back door - the Chicago Sanitary and Ship Canal.

Three times in recent months Canadian officials have caught truck drivers with thousands of pounds of live bighead carp, which Canada banned in 2005.

The first bust on Nov. 4 resulted in a $50,000 fine. A Feb. 18 seizure netted 6,000 pounds of the remarkably fecund fish and landed an Indiana fish hauler a $20,000 fine. A third case is pending.

The good news:

"Ontario is on the ball," said Marc Gaden, spokesman for the Great Lakes Fishery Commission. "They're looking for these fish, are able to identify them and they're willing to actually prosecute.

The bad news:

"Like an iceberg, this is the part you can see," Gaden said, "but you wonder how much of this trade is really going on."

All of this comes as the Corps of Engineers is plowing ahead on a $15 million study to figure out how to keep Asian carp out of the Great Lakes, by somehow plugging the Chicago canal system that has destroyed the natural ecological barrier between Lake Michigan and the Mississippi River over a century ago.

Canadian fishery officials say the bighead they've stopped at the border apparently are coming from fish farms in the Southern U.S.

Asian carp originally were imported into Arkansas in the 1960s and 1970s, where they were raised to clean fish farm ponds and sewage lagoons and, later, as a food fish. There are four species of Asian carp - grass, black, silver and bighead.

All four species have since gotten loose in the wild, but the filter-feeding silver and bighead carp are the ones making headlines. These are the fish that have made it all the way to the Chicago canal system and are now knocking on the door of Lake Michigan.

Silver carp have essentially no commercial value and are no longer raised on fish farms in any large number, but bighead are still being raised as a commercial product in the South.

Until the recent seizures, the last bighead bust at the Canadian border was in 2006, the year after Canada banned the possession of all species of live Asian carp. But Canadian fishery officials say the recent arrests aren't necessarily an indication that more fish are being moved north.

Bill Ingham, an intelligence and investigations officer with the Ontario Ministry of Natural Resources, said the recent seizures likely have something to do with a focus on stopping the fish at the border instead of trying to track them down at food markets in big cities like Toronto. Bighead are a popular food fish among some Asian groups.

"It's a swing in tactics that has produced a large success for us," he said.

The U.S. federal government designated silver carp as an "injurious" species under the Lacey Act in 2007, meaning it is now illegal for the fish to be transferred live across state lines. Bighead didn't get the listing until last December.

And it is that bighead listing that has left Southern fish farmers few options to sell their crops, at least live - the preferred state for most customers.

"A few farmers are still raising bighead carp, but that will probably decrease soon," said Mike Freeze, a former chairman of the Arkansas Game and Fish Commission and a fish farmer. "They cannot get as much for them dead on ice as they could live."

Freeze said he believes most farmers are not intending to ship live product. The problem is that the fish are apparently surviving for more than 24 hours in the waterless tanks on their way north.

Ingham noted that even though the confiscated fish were indeed transported in tanks with a little ice and no water, some still showed up at the border twitching, gasping, and in some cases flat-out writhing.

If they were to be dumped into open water, the fear is some could survive long enough to breed.

U.S. government officials have stated repeatedly that they worry that commercially raised fish will be set loose in open waters as part of a phenomenon known as "cultural releases," which they say is a practice among some Asian groups. There is indeed documentation of commercially produced animals being set free in Asia, though questions remain as to whether it has happened in North America.

The Southern fish farmers themselves haven't been the target of any of the Canadian operations, Ingham said, because "they're conducting a legal business."

It is, he explains, the haulers who are breaking the law, and Ingham said even the people driving the trucks appeared surprised the fish were surviving out of water. Still, they are being slapped with heavy fines.

"I do not have much sympathy for someone who intentionally breaks the law, but I am quite concerned about the heavy Lacey Act penalties that apply even in an accidental violation," said Arkansas' Freeze.

Ingham said there is one thing fish haulers can do to ensure they aren't breaking any laws.

"Eviscerate them," he said.

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