American exports

Fast links to two articles about North American crayfish causing problems elsewhere.

One is in National Geographic, and looks at Africa:

The 6-inch-long (15-centimeter-long) invader is already widely distributed in lakes and other bodies of water throughout Kenya, as well as in Rwanda, Uganda, Egypt, Zambia, the Seychelles, Mauritius, and South Africa.

Conservationists are now concerned the crayfish will reach the East African lakes of Malawi, Tanganyika, and Victoria, which are home to hundreds—and probably thousands—of species found nowhere else.

My understanding is that one solution to the invasion, fishing crayfish for food, may be a particularly tough sell in Africa. Apparently, many of the locals view eating crayfish in much the same way that North Americans view eating insects.

Another is in Scientific American:

Virile crayfish were first spotted in East London’s waterways in 2004, probably after being dumped into a pond from a home aquarium. Since then, they have colonized 17 kilometers of the River Lee and surrounding waterways. River Lee has no native white-clawed crayfish left—they were all wiped out by the signal crayfish invasion in the 1980s.