something about crabs..

The Navarre native crayfish almost completely disappearances many years ago illegally introduced American species, perhaps thinking that introduced that would increase the chances of capture.

   As is almost always that man introduces a new species in an ecosystem, this was a terrible mistake, it was afanomicosis carrier, a fungus that are immune to two types of American crayfish (crayfish and signal crayfish), but deadly to the native.

Survives today only in racing headers to which Americans have not arrived.

While the American is, the native can not return to their old places, because the disease survives in American guests.

In this photo taken from the reservoir lake of Irabia, we can see the signal crayfish, present in almost all rivers in Navarre, and identifiable by the white markings of the tweezers.
The crabs play an important role in cleaning rivers, work now performed by American crabs to have kill  the locals.
it is important that Irati racing crabs remain free, because otherwise they could end up eating the eggs and kill anfibiosn protected species such as the Pyrenean frog or russet frog.