Fisheries scientists are trying to wipe-out an alien fish species from two lakes in Devon in which it has undergone a population explosion.
Officials from the Environment Agency will this week take the first steps towards eradicating the Topmouth gudgeon or Clicker barbs, Pseudorasbora parva, from lakes at Bicton College and Bicton Gardens in East Budleigh in East Devon.
The fish species, which is illegal to keep in the UK under the Import of Live Fish Act, is the Environment Agency's enemy number one and is classed as a category five risk species - the highest level of risk.
Although the Asian cyprinid fish only reaches an average size of 5cm/2", the species is causing big problems for native fishes in the UK.
Mike Dunning of the Environment Agency said: "It can out-compete native species such as roach and rudd because it matures at one year old, whereas a rudd does not sexually mature until two or three it. It can also breed up to four times a year."
Dunning says the the Environment Agency installed a gravel filter on the lake at Bicton College recently in an effort to contain the fish, but the lake overflowed and a number of the fish were washed past the filter and into the nearby Bicton Stream.
Says Dunning: "Agency fisheries officers later collected around 6000 of the fish from the stream following the thunder storm break-out. It is estimated that there could be up to 100,000 of the tiny invaders in the smaller lake alone."
The Environment Agency is electrofishing a 400-500 metre stretch of Bicton Stream today to try and remove the fish.
Other measures have also been introduced at Bicton so that anyone using the lake does not inadvertently spread the species by transferring the fishes' eggs to other waters.
All people using the water must now disinfect their shoes, boots, boats and fishing equipment before leaving the site.
In February 2005, the Environment Agency used a poison to kill the resident population of Clicker barbs in Ratherheath Tarn in Cumbria.
A study undertaken in June last year showed that the fish carry a parasite that is found on healthy specimens and is capable of wiping out many European freshwater fish species.