TORONTO - Ontario is proposing to allow only gutted Asian carp into the province to prevent the introduction of the ravenous intruder into the ecosystem.

The Ministry of Natural Resources (MNR) released a discussion paper Monday that notes it's illegal to possess, buy or sell live Asian carp in the province.

But almost 175,000 kg of Asian carp were imported in 2011 alone as food, and the fish arrives at the Ontario border alive in holding tanks full of ice, MNR says.

In some cases, cargoes have been seized because the fish were still alive during the actual crossing.

"Experience in the U.S. has demonstrated that it is virtually impossible to eradicate Asian carp once they have become established within a waterway," MNR says. "Prevention is the key. And fisheries experts agree there is only one way to be really sure that these fish are dead when they get to the border: To eviscerate them by removing their internal organs."

The discussion paper says consumers would still enjoy fresh fish while the ecosystem would be protected from an invasive species.

MNR says Asian carp, which include bighead carp and silver carp, have been heading north through U.S. waterways and are now an "imminent and very serious threat to the Great Lakes."

"Asian carp are voracious consumers, eating up to 20% of their body weight each day, and can grow to reach more than a metre in length and 40 kilos in weight," a MNR backgrounder says. "Bighead and silver carp eat plankton...the very foundation of the food web."

Beyond the impact on the province's important fishing industry, Asian carp could impact recreational activities as well, the paper says.

"Certain types of Asian carp are also a hazard for boaters and water skiers," MNR says. "The vibration and sound of boat motors can cause silver carp to jump up to three metres out of the water, damaging property and seriously injuring those nearby.

"One woman was almost killed when she was knocked unconscious from her personal watercraft by a 'flying' silver carp in a US waterway," the ministry says.