Alien invaders threaten Humber fish life Published: 20 February, 2007
FISH, and other marine in life in the Humber, is being seriously threatened by an alien invader – the Chinese Mitten Crab.
But this latest warning from the environmental group Nature England also comes with the claim of a more serious threat – the risk of flooding.
It appears that the Mitten Crab, already a threat in other river areas of the country, is eating into the river banks around the Humber and the estuary area and gradually destroying the flood defences.
The problem in the Humber is thought to be more advanced that in other parts of the country. Alex Smith of Nature England said: “The Chinese Mitten Crab is a voracious animal with a massive appetite and it is breeding very fast.
“We have also found that it is not just the environment at risk, but these crabs are also attacking marine life, including the Humber fishery, which is very important to many people.”
Mr Smith said they were also migrating across large tracts of land to other waterways along the East Coast. Nature England is now looking at how the problem can be tackled.
He said the Humber was one of the largest shipping areas in the country and the crabs are thought to have been coming in for many years in water ballast tanks and other containers and then escaping when the water is thrown out.
The mitten crab can travel extraordinary distances. In China, it migrates up to 1,500 kilometres along some rivers. However, shipping practices can transport the crab much further – all the way to Europe and North.
For reasons that are not understood, the populations of mitten crabs in England and North America did not at first expand like those in mainland Europe. But numbers are currently rising, prompting widespread alarm. The mitten crab is capable of causing structural problems, because it can burrow into fragile mud riverbanks, riddling them with holes until they collapse.
If any fishermen or members of the public have spotted a Chinese mitten crab, the environmentalists would love to hear from you. The more information members of the public can provide, the more it will help them.
Meanwhile, Nature England has been involved with a project which has completed a new survey of the seas around the UK, giving a complete picture of habitats.
Now for the first time a more complete, broader picture has emerged following a two-year project to produce a new map of the sea that shows 44 large-scale ‘marine landscapes’.
Marine landscapes reflect the equivalent of mountains, valleys and plains of the marine environment, together with major habitat types. The UK Sea Map project is a partnership of ten organisations including Government Departments, agencies, advisers and conservation charities.
David Connor, a marine specialist who led the work at the Joint Nature Conservation Committee, explains: “Through our understanding of the physical and hydrographic factors that determine what wildlife occurs where, such as seabed sediments and water depth, we have developed an approach to predict variation in seabed ecology, using data that covers large areas.
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