KANSAS CITY, Kan. — By the hundreds of thousands, foreign fish push against the current to the side of where water rolls over an old dam in suburban Kansas City.
The school of fish stretches as far as can be seen down the Kansas River. Fish are so thick, a quick scoop with a fishing net grabs 50 or more.
They're Asian carp, and though now only 10 inches long, some could reach 100 pounds and take huge bites out of Kansas' $250 million sport fishing economy by crowding out native fish.
Some could also eventually endanger boaters and skiers because, when a boat passes, the fish panic and jump, becoming 10- to 60-pound missiles and occasionally smacking into people.
For now, the Arkansas River is free of the dreaded fish. But a few Asian carp have been found in the Verdigris and Neosho rivers of south-central Kansas.
Biologists fear they could spread to the Arkansas River with help from anglers.
The Asian carp on the Kansas River may have arrived with those who stand to lose if the invasion becomes widespread — anglers illegally catching the fish, which they've mistaken for bait.
State wildlife officials are trying to educate people of the catastrophe that might come from moving invasive species to new waters.
Those using the fish for bait or transporting them can be fined up to $500.
"We've observed (anglers) putting them in bait buckets and taking them somewhere else," said Doug Nygren, Kansas Department of Wildlife and Parks fisheries chief. "That's scary. We don't want these things in our lakes and reservoirs."
Such movement could lead to disaster, according to Nygren.
"Even one bait bucket-full can create problems," said Duane Chapman, an Asian carp specialist with the U.S. Geological Survey. "It only takes one silver carp to kill you if you're a water-skier."
Jason Goeckler, Wildlife and Parks aquatic nuisance species coordinator, estimates 1 million or more just-hatched Asian carp live in the Kansas and Missouri rivers and their tributaries.
Most of the Asian carp threatening Kansas are of two species — silver and bighead carp.
Silvers are the jumpers and usually weigh 20 to 40 pounds. Bigheads aren't prone to jumping but can reach 100 pounds.
According to Chapman, both got free rides to the U.S. in the 1970s from the American aquaculture industry hoping to develop Asian carp into a food fish and algae-eater in sewage waters.
In the 1980s, some escaped and found their way into the Mississippi River and eventually its tributaries.
In the 1990s their population exploded.
The U.S. Fish and Wildlife Service reports that the catch of Asian carp by commercial fishermen on the Mississippi increased from 5.5 tons in 1993 to 55 tons in 1997.
In some rivers they probably make up more tonnage than any other species.
Estimates vary on the percentage of the fish that are Asian carp in infested American rivers.
But Chapman said a cyanide spill in eastern Europe, where Asian carp are also a problem, killed all fish in long stretches of the Danube River. More than 90 percent were Asian carp.
Asian carp have little value as a food fish for humans in the U.S. They are almost impossible for recreational anglers to catch because they feed on plankton. They offer little forage for native fish.
Currently the biggest battle in the United States is being fought on the Illinois River. Wildlife officials fear the fish will move from the Illinois into the Great Lakes, threatening commercial and sport fishing worth up to $7 billion annually.
To keep the fish out, electric currents are passed through the water at key places to discourage fish movement. Tons of native fish have been poisoned when it's feared Asian carp may have slipped into the system.
Fish and Wildlife officials say up to 1,000 pounds of Asian carp are routinely found in one half-acre of the Illinois River.
Steve Schultz of the Illinois Department of Natural Resources said they out-compete native fish for food. That means the numbers, size and overall health of most native species in the Illinois River are suffering.
So are some people.
Numerous pleasure boaters, anglers and skiers have been hit by silver carp going airborne when a boat passes.
Trying to safely maneuver a boat through a leaping school, which can contain hundreds of fish, can be nearly impossible. With the fish commonly weighing 20 to 40 pounds, they can pack a punch.
Chapman, widely recognized as America's top Asian carp authority, has heard of numerous serious injuries from jumping carp.
Since Kansas waters are as fertile as those in Illinois, Kansas could end up with a similar problem.
"I hated to think we could ever get to be like the Illinois River," Goeckler said. "But that's where we could be headed if we're not careful. Things have changed a lot this year."
Goeckler said adult bighead carp were first found in the Kansas River in 1993. Silver carp showed up in 2006.
Last summer the first and only juvenile Asian carp was found in a Kansas stream.
The masses now on the Kansas River began showing up a few weeks ago. Goeckler and other biologists estimated a gathering of about 300,000 young Asian carp at the dam near Kansas City recently.
Chapman credits ideal spawning conditions from this year's heavy rains, which created lots of shallow, calm backwater along the Missouri River, for the population explosion.
The fish are probably here to stay in the Kansas River and below all dams on its tributaries. But aquatic experts say it's imperative that the bighead and silver carp not get a hold in Kansas' reservoirs or lakes.
Chapman said the fish could thrive better in lakes — their native habitat in Asia — than rivers.
Since both species of carp feed almost exclusively on tiny plankton, they'll compete for food with the very young of all fish species.
And they'll win. Asian carp consume 5 percent to 20 percent of their body weight in plankton daily.
Gizzard shad could be a major loser. The plankton-feeders are at the base of most aquatic food chains in Kansas lakes because they're the most common food of Kansas game fish.
Indirectly, Chapman said, deep-water fish such as walleye, crappie, wipers and stripers would be the game fish most affected.
All rely heavily on shad and spend much of their time feeding in the deep water, where Asian carp also prefer to feed.
Nygren's biggest nightmare is for the carp to become established in one of Kansas' larger reservoirs, such as Milford, Tuttle Creek or Perry.
In years of high rainfall, Asian carp could possibly find good spawning conditions up the major rivers that feed those lakes.
"It wouldn't happen every year but it would only need to happen once and we'd be seeing in our lakes what we're seeing on the Kansas River," Nygren said. "They could totally take over one of those lakes in a hurry."
In just a few trips to the old dam near Kansas City, biologists have seen several anglers attempting to haul Asian carp to other places.
Nygren said anglers probably think they're netting schools of shad, which look like young Asian carp.
He also fears the possibility of anglers capturing Asian carp below dams at lakes like Clinton and Perry and releasing them on the lake after using them for bait.
Possessing, moving or releasing prohibited species from one water to another are misdemeanors punishable by up to 30 days in jail and up to a $500 fine.
Nygren hopes education will have the biggest impact on Kansans.
"If they care at all about our reservoirs and lakes, they need to help us keep these things out," Nygren said. "This is very important stuff we're dealing with right now."