Asian Carp Could Devastate Great Lakes

Unless we act fast, the Great Lakes are about to be
invaded by giant fish so voracious, says biologist
GAIL KRANTZBERG, they'll devastate the ecosystemBy GAIL KRANTZBERG
Monday, August 26, 2002 – Page A13

This is an alert to all things that live in the Great Lakes. Beware. The voracious alien Asian carp is poised to invade. The environmental and economic havoc that would likely result make the problems associated with the infamous zebra mussel pale by comparison.

Asian carp grow rapidly and have ravenous appetites. They can reach the size of a healthy teenager, and may be up to 50 kilograms in weight and two metres long. They can increase by five kilograms per year, and eat half their body weight daily. And they are extremely prolific, with fertile females producing as many as a million eggs each.

Vacuuming up microscopic plants and animals, Asian carp can compete for food with virtually every juvenile sport and commercial fish, which forecasts widespread injury to our multibillion-dollar fishery. If these carp enter the Great Lakes, there is a very high probability that the ecosystem will be hugely and irreversibly injured.

Asian carp were imported from China in the 1970s to control pests, such as excessive algae, in Arkansas fish farms. Scientists believe the carp escaped from the aquaculture operations during flooding in the 1990s. Widespread in the Mississippi and Illinois Rivers where the commercial fisheries are reeling, they were recently found only 40 kilometres from the Chicago Sanitary and Shipping Canal, a man-made entranceway to Lake Michigan.

There is an imminent peril that we will infect our lakes with these fish through the Chicago Sanitary and Shipping Canal. A marvel of engineering design, the canal opened in 1900, reversing the flow of the south branch of the Chicago River away from Lake Michigan, dispatching Chicago's sewage to the Illinois River and from there, down into the Mississippi River. The connection between Lake Michigan and the Illinois River affords the Asian carp an artificial portal to the Great Lakes.

Herb Gray and Dennis Shornack, co-chairs of the International Joint Commission, warn that these fish could essentially wipe out the base of the food chain in the Great Lakes. The Great Lakes could become one giant carp pond. The commission is now appealing for government action to ensure the invasion into our lakes is prevented.

The U.S. Army Corps of Engineers has built an electrical barrier in the canal to stop Asian carp, but it is not clear this will be sufficient. Other irritants, such as noise and bubbles, could be added for maximum effectiveness in repelling carp. Carp are sensitive to loud noise and will flee from it, and the bubbles would create a visual barrier to act as a further deterrent.

The commission has called for a fully funded program that will keep the existing barrier operating until another solution is found, and for an additional investment in backup power to supply the barrier.

The costs of these undertakings, approximately $1-million (U.S.) for both, are inconsequential compared to the massive, multibillion-dollar economic damage should an invasion of these monsters devastate our fishery. The livelihood of commercial fishers, angling charters, local ports and spinoff tourism industries such as hotels, restaurants and retailers would be seriously damaged.

Even if the Asian carp can be prevented entry at the Chicago canal, the risk is not eliminated. Many people practise the Asian tradition of releasing one fish for every one they eat, as a way of increasing personal karma.

Prohibiting the import of Asian carp as food fish could mitigate this risk. A public education program could help prevent people from intentionally introducing Asian carp into our lakes. An aggressive campaign aimed at fishers to explain why the baitfish they may be dumping into the lake could be a future nightmare would also be a good idea.

We have learned of the massive and growing insults our lakes face from alien invasive species. We did not stop their import even after zebra mussel populations exploded and showed us all the damage such invaders could perpetrate. Zebra mussels prefer to form colonies on hard surfaces where there is flowing water, interfering with the intakes of water treatment plants, motors of recreational vessels, and discharge pipes. Costs for treatment and control of zebra mussels alone in the Great Lakes reach several billion dollars annually. If Asian carp enter the Great Lakes, the damage to our ecosystem and our economy could surpass these figures.

The Great Lakes continue to acquire a new invader each year, bringing the total of such imports to a shocking 160 species, most unintentionally introduced by vessels coming from overseas into the Great Lakes. We need to manage the ballast water in those vessels, and the sludge and sediment at the bottom of ballast tanks to end the invasion from this source.

As for Asian carp, we need to take action immediately. An ounce of prevention is mandatory because there is no cure. If we react thoughtfully, but rapidly, we can stop Asian carp and we can convince individuals that they can contribute to the solution. The need to act is urgent. The time to act is now.
Gail Krantzberg is director, Great Lakes Region Office, of the International Joint Commission.