ScienceShot: Guppies Where You Least Expect Them

Chalk up another conquest for the humble guppy. The tiny, brightly colored South American fish has long been a favorite of aquarium owners, and is also one of Earth's most successful invasive species, having expanded its range to every continent except Antarctica. Now, the guppy (Poecilia reticulata) has seized some unlikely new territory: It is the first freshwater fish ever found on the Cape Verdean archipelago, a chain of ten parched volcanic islands off the west coast of Africa. Just one of the drought plagued islands has streams that run year-round, researchers report in the current issue of African Zoology, and the only known freshwater animals were invertebrates such as snails and dragonflies. In late 2011, however, researchers from the University of Bern in Switzerland discovered guppies swimming in a concrete irrigation reservoir on the island of Santa Antão. The fish might have been imported by a pet lover, the researchers speculate. And it's not too soon to consider ways of eliminating the invaders, they add, because rapidly multiplying guppies are a well-known threat to native species.

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