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Chinese crab invading UK waters
08/02/2006 14:27 - (SA)
London - An exotic Chinese crab which preys on native British species is on the verge of taking over the country's major waterways, environmental experts warned on Wednesday.
Mitten crabs, which can grow to the size of a dinner plate, could threaten other marine life, just as grey squirrels have pushed British reds to the verge of extinction, researchers at Newcastle University, northeast England, said.
They compared how mittens had swept through continental Europe in the last century with their progress through British waters today, and concluded there could be a population explosion in all major estuaries in several years.
Matt Bentley, from the research team, said: "The pattern of the spread in the United Kingdom since the 1970s mirrors the spread in mainland Europe and in the Baltic region which experienced a major outbreak.
"This is a fairly good indication that the UK is set for a similar situation."
River banks can be destabilised
Mittens - so-called because of the small clumps of dark brown fur on their claws - were brought to Britain in ships' ballast water and are present on major rivers like the Thames in London, the Humber and Tyne in northern and northeast England.
The creatures, which can survive in both sea and fresh water and are adept at moving over land, prey on protected species native to British waters like white-clawed crayfish and salmon eggs.
They also destabilise river banks by burrowing into them.
The study, published in the academic journal Biological Invasions, recommends the introduction of a nationwide monitoring and trapping system for mittens before it is too late to control their spread.
"With most invasive species, such as the grey squirrel, the problem is not recognised until it is too late to do anything and you cannot eliminate it without taking drastic environmental measures," said Bentley.
- AFP
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