BBC News – Chicago goes to war with Asian carp


BBC News – Chicago goes to war with Asian carp.

These fish were imported decades ago to control algae in sewage treatment ponds.  After escaping, they have spread up the Mississippi River, displacing native species.  Now they threaten the Great Lakes.

How?, you might ask, since there is no natural connection between the US’ largest river and the lakes which hold 20% of the world’s fresh water?  Why the Chicago Sanitary and Ship Canal, of course!

Completed in 1900, the canal is the only link (via the Des Plaines River) between the lakes and the Mississippi.  It diverted Chicago’s sewage from the lakes (where they got their drinking water) to the river, which carried it away from the city.

The Canal is a vital link in the transportation system in the US, allowing goods from all over the world to move freely between the lakes and the river.  Proposals to close the canal to prevent the carp from invading the lakes are on the table, but

…from an economic standpoint it will affect shipping that folks in the UK and other parts of the world might rely on to get their goods and services here because they are going to cost more to transport.”

How to keep the lakes carp free?  There are no easy answers.  Closing the canal would result in higher transport costs for too many people, while another invasive species in the Great Lakes is seen as the cost of globalization.

Squeezing Out the Natives

Pythons Eating Through Everglades Mammals at

via Pythons Eating Through Everglades Mammals at “Astonishing” Rate?.

From rabbits to deer to even bobcats, invasive Burmese pythons appear to be eating through the Everglades’ supply of mammals, new research shows.Since the giant constrictors took hold in Florida in 2000, many previously common mammals have plummeted in number—and some, such as cottontail rabbits, may be totally gone from some areas.

Pythons, an invasive, non-native species, have been let loose in Florida, probably by owners who tired of them.  The climate is conducive to their survival and reproduction, so they have emerged as a threat to many native species of Florida’s animals.

Indigenous animals are adapted to the local predators, but the introduction of this exotic snake has wreaked havoc on the ecosystem.  Many mammals seem to have disappeared from the local fauna, and others have declined precipitously.

Raccoon observations dropped by 99.3 percent, opossum by 98.9 percent, and bobcat by 87.5 percent. The scientists saw no rabbits or foxes at all during their surveys.

At some point a new balance point will be reached – without food, pythons will die off, which will allow some species to rebound.  But the ecosystem is altered.

“We have taken strong action to battle the spread of the Burmese python and other nonnative species that threaten the Everglades and other areas across the United States,” Secretary of the Interior Ken Salazar said in a statement.

“There’s no single solution to this conservation challenge, but banning the importation and interstate transport of these invasive snakes is a critical step.”

Invasive species are changing ecosystems around the world,  What will the future hold?  How will the indigenous species cope with invaders?  Only science and time will tell.

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