Friday 4 February 2011

♥ Conservation Of White Clawed Crayfish Is Important For Ecology Status Of Water Bodies


White clawed crayfish (also called Austropotamobius pallipes or Atlantic stream crayfish) is the Britain’s only native fresh water species. The native cray fish is olive-brown in colour, they have large front claws of pale pink-white colored underneath, which they use for collecting food and display at the time of breeding. They are up to 15 cm in size and their food is larvae, snails, and plant leaves. White clawed crayfish are found largely in fresh oxygenated water in lakes, streams and rivers. They play a vital role in helping us understand ecological status of our rivers and water bodies.

In recent years the conservation status of White clawed crayfish has declined drastically and this mini-lobster lookalike species have been listed as “endangered” in the Red List of Threatened Species by International Union for Conservation of Nature (IUCN). Due to its severe decrease in population the UK legislation have given this species protection under Wildlife and Countryside Act 1981 (as amended) and The Conservation (Natural Habitats, &c.) Regulations 1994. As per the law to kill, injure, sell or advertise to sell the white clawed crayfish is a legal offence and a person is guilty to pay £5000 as fine.

The major cause for such a huge decline in the population of white clawed crayfish is due to the increase in population of invasive American signal crayfish. These non native species of crayfish are very aggressive in nature and carry a plague that has devastating effects on our native white clawed crayfish and other aquatic living beings. The plague spread by the American signal crayfish contaminates the water, which resulted into the loss of almost 95% of white clawed crayfish population in recent years.

The Natural England has released biodiversity action plan to restrict the spread of signal crayfish plague and increase the breeding of white clawed crayfish. As per the last update in year 2008 from BBC news, says that “the captive breeding program for increasing the population of white-clawed crayfish has produced 300 young this year in the Yorkshire Dales”. The program was launch in year 2003 by taking steps such as ring fencing to protect the white clawed crayfish from American species plague. Such type of progress is an encouraging factor in to conserve white clawed crayfish.

White clawed crayfish survey and mitigation is adopted to save the native species. Only a Natural England licensed ecological consultancy can conduct white clawed crayfish survey and mitigation. Various techniques such as night time searches using torch are adopted for white clawed crayfish survey. Generally the survey is done between mid July and end of September and when the river flow is low. Any development near water bodies will require white clawed crayfish survey and mitigation.

The ecological consultancy helps in conducting white clawed crayfish mitigation. The mitigation techniques used are the relocation of white clawed crayfish, creating white clawed crayfish habitat through installing stone walls fencing, improving vegetation to provide food. For any development work near the area where white clawed crayfish is present, will require mitigation by moving the white clawed crayfish to a new habitat and then again re-colonize once the development work is over.







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credit : articlecity.com

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