Alien Species Invading The British Isles

“An armor-plated alien invader is eating its way through wildlife in Britain’s waterways”

So reads The Daily Telegraph this week. Who said that environmental journalism can be dull?

The invader in question is the American Signal Crayfish (pictured), described as a six inch long killing machine and voracious predator that has already annihilated the native White Claw species, and now threatens to completely overwhelm many fragile aquatic eco-systems.

The problems started during the 1970’s when Signal crayfish bread in farms for the restaurant trade managed to escape. So successful have they been, with their lack of natural predators, rapid breeding rate, and willingness to eat absolutely everything including plants, insects, fish, snails, detritus and their own young, that they have quickly grown into an aquatic army of almost plague proportions.

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River banks, already under pressure from flooding (and interest rates - sorry), are beginning to collapse as the crayfish burrow up to three feet into the banks, laying more than 250 eggs at once. At the same time, the fact that absolutely everything is on the Signal’s menu means that all other species effectively face the firing squad when the Signal crayfish arrives, either by land or water - the Signal can walk for several miles on dry land in search of new killing zones.

This all sounds nasty enough, but what surprised me even more is just how large the problem of species invasion has become. The Guardian has a short slide-show of foreign invaders, and introduced-species.co.uk is currently tracking 91 different invasive species and their impacts on native eco-systems.

What can we do about this? Not very much it seems. Every time mankind tries to manipulate our environment we usually seem to make a huge mess. Scientists are currently considering plans to breed large numbers of sterile male crayfish, releasing them into the world to upset breeding rates - probably not a bad plan, although adding even more of the monsters to the population does appear risky in the short term.

As usual, the problem comes down to ourselves, the original invasive species. One day we might find a way to stop making these mistakes, but until then we’ll just have to live with the consequences of our good intentions. At least crayfish taste good.

Image credit: david.nikonvscannon at Flickr under a Creative Commons license

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