Transporting several species of Asian carp across state lines became a federal offense last year, thanks to actions taken by the U.S. Fish and Wildlife Service.
Missouri officials say the ban is a good first step toward stopping the spread of the potentially harmful exotic fish.
The ban on silver carp went into effect in August 2007, followed by the ban on black carp in November. The federal laws make it illegal to transport live black, silver or largescale silver carp from state to state. The prohibition was accomplished through rule changes under the injurious wildlife provisions of the Lacey Act. The Fish and Wildlife Service took the actions at the request of members of Congress.
The most likely way that a sport angler could transport the banned fish would be by unintentionally including juvenile carp with wild-caught baitfish. Live Asian carps are not permitted as baitfish in Missouri, so anglers who use bait should be familiar with the appearance of juvenile Asian carps and take care not to include them as baitfish. Those who catch their own baitfish are warned that inclusion of Asian carps in baitfish that are transported across state lines would now also be a federal offense.
"Slowing the spread of these carp is necessary to protect our native aquatic species," said Fish and Wildlife Service Director H. Dale Hall in announcing the ban. "Although silver carp are established in parts of the Mississippi watershed, we will work to keep their impacts minimized and prevent additional populations from taking hold."
Several Asian carp species have become established in the Missouri and Mississippi rivers and their larger tributaries in Missouri in the past 30 years. Some -- notably the silver carp -- have the habit of jumping out of the water when motor boats pass by.
As the fish have become more numerous, so have injuries to boaters and skiers who are struck by hefty fish at high speed.
Biologists worry about the ecological effects that exotic species without natural population controls might have on native fish.
"They are becoming very numerous in our big rivers," said Tim Banek, invasive species coordinator for the Missouri Department of Conservation. "They are not fish-eaters.
They filter water for plankton, mostly microscopic organisms that form the base of the food chain in many waters."
Banek said that puts the Asian carp in potential competition with some native fish species, such as paddlefish and buffalo.
One recent study in Illinois shows that native fish weigh less since the Asian carp invasion, and a study by the U.S. Geological Survey in Columbia showed that the presence of bighead carp was associated with reduced condition of paddlefish.
Other native fish, including shad and emerald shiners, which also depend on plankton for food, in turn provide food for sport fish ranging from crappie and largemouth bass to blue catfish.
Unlike shad and other plankton-eating fish that remain small enough for sport fish to eat, the Asian carp can grow very large.
The world bowfishing record bighead carp was shot in the Mississippi River adjacent to Missouri in May. The fish weighed 92.5 pounds. Their large size not only makes them dangerous to boaters, it also increases the amount of food they take from native fish.
Banek said silver carp have multiplied rapidly in the Missouri and Mississippi rivers and in the mouths of their tributaries. One potential way of controlling their numbers is through commercial harvest. However, he said there currently is not a substantial market for the fish. Other uses that are being tried for them include food for zoo animals and fertilizer manufacturing.
Asian carps are somewhat boney, but their meat has excellent flavor. Many sport anglers and bowfishers now are eating the fish.
The ban applies only to live fish, so transporting dead exotic carp or their flesh is legal. There is no limit on the banned fish.