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White Clawed Crayfish Are In-decline in the Uk

Updated on October 4, 2015

The River Kent in Cumbria

The meandering river Kent-Cumbria.Photograph courtesy of Peter Moore.
The meandering river Kent-Cumbria.Photograph courtesy of Peter Moore.

Notes from a Lancashire Countryman

Being a countryman, my love for rivers meandering through picturesque scenery, is ingrained in my soul. Rivers are permanent yet always moving, movement is life. Rivers and their riparian habitat are teeming with wildlife which varies in diversity from the the tiniest of aquatic larvae to large mammals like the otter.

One of my favourite rivers is a relatively short one that originates in the heights of Bleathewaite Crag in the Lake District. The river Kent runs for approximately 20 miles from the region of the Kentmere Valley and flows to its estuary in the north of Morecambe Bay Lancashire. Other rivers such as the Gowan in the north and the Gilpin at the southern end of its journey join the Kent.

The river Kent boasts salmon and trout among its fish population with a well known salmon "leap" at the wier at Barley Bridge in the village of Stavely. Fly fishing is common place at the rivers which are so numerous in the Lake District. I like to stop and observe these patient gentlemen , as they swish their lines back and forth, as they pit their wits against the wily trout. In the clear waters of many rivers trout can be seen basking in the glittering reflections of the sun. Rainbow trout are beautifully coloured members of the fin folk.

Top. Fly fishing. Bottom Rainbow trout

These patient gentlemen pit their wits against the wily trout. Photograph courtesy of Ziga
These patient gentlemen pit their wits against the wily trout. Photograph courtesy of Ziga
The rainbow trout is a colourful fish. Photograph courtesy of
The rainbow trout is a colourful fish. Photograph courtesy of

Special Area of Conservation

Another inhabitant of the river Kent has been a major factor in the River being designated as a Special area of Conservation {S.A.C.}. The White Clawed Crayfish, Austropotamobius pallipes, is our only native species and its numbers are in decline. This has led to the species being classed as a Priority Species of Conservation Concern, under the U.K. Biodiversity action Plan. The classification means that an Action Plan has been formulated and is currently being implemented on behalf of the species in order to halt and hopefully reverse the decline, trying to regain their former numbers and contribution.The white clawed crayfish has full legal protection in the U.K. appearing on Schedule 5 of the WildLife and Countryside Act 1981 {as amended}

Cray fish are the largest , most mobile fresh water invertebrates and are considered a key species to predict the health of a river, for they are prone to pollution. Adults may reach over 12cm long from the tip of their rostrum {snout} to the telson {tail plate}, but a more average size is 10cm or slightly less. The body is smooth, generally brown to olive in colour, and has a pitted appearance. The male has larger claws and is generally more territorial, especially in the breeding season. They were once numerous and widespread in Britain where conditions were suitable but many populations have been decimated by crayfish Plague-see below. The dense population are now confined, in the main, to central and northern Britain. However, they are regarded as being of European importance. The ideal habitat for these aquatic creatures is relatively shallow water with rocks along the bed and soft banks which enable them to burrow.

They are hunted by pike, otters, and other large fish, heron, crow and mink. Apart from the latter {another introduced species that has been released into the wild} Nature makes allowances for natural enemies.


Cray fish are mobile creatures that are under threat. Photograph courtesy of N.P.S.
Cray fish are mobile creatures that are under threat. Photograph courtesy of N.P.S.

What Has Gone Wrong?

So what has caused the decline in the species populations.The Species Action Plan conveys that among other complex components, the crayfish plague is a serious threat, which has been carried into our rivers by the introduced North American species the signal crayfish. This species is readily identifiable by the red colour, particularly on the underside of its claws. The signal crayfish-Pacifastulus leniosculus, is one of the three non-native species currently breeding in the wild in Britain. It is a serious threat to our native species.

The crayfish plague is a fungal disease whose spores can be carried by the water itself and fish.The three introduced species are in direct competition for food and habitat. Habitat modification, fragmentation and mismanagement of habitat and pollution, especially sewage and pesticides have all contributed to the decline.

Halting the Decline

The Species Action Plan has several ways and means at their disposal to combat the decline. These include using the Fisheries Legislation to regulate the keeping of non-native species. The three non-native species now appear on Schedule nine of the Wildlife and Countryside Act 1981 {as amended- see my hub Wildlife and the Law}, which makes it illegal to release them or allow them to escape into the wild.

B-to combat pollution such as pesticide and herbicide run off.

C-to ensure appropriate management of suitable habitat

d- introducing white clawed crayfish into suitable habitat, especially where they were known to thrive in the past.

The plan for the crayfish will also benefit associated river species and more importantly the health of our rivers, a healthy river will support a rich diversity of wildlife that can only enhance these riparian havens of beauty.


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    • D.A.L. profile imageAUTHOR


      9 years ago from Lancashire north west England

      Kaie Arwen, your welcome and thank you for your kind comment which is appreciated.

    • Kaie Arwen profile image

      Kaie Arwen 

      9 years ago

      I love your Hubs! Thanks for this!


    • D.A.L. profile imageAUTHOR


      9 years ago from Lancashire north west England

      hynodude, Good to hear from you again. The problem of declining species seems a worldwide problem sadly. Thank you for reading and for leaving your comment.

    • hypnodude profile image


      9 years ago from Italy

      In Italy wild cray fish is almost disappeared, I let you imagine why. Beautiful hub as usual, and great pictures. Thumbs up!

    • D.A.L. profile imageAUTHOR


      9 years ago from Lancashire north west England

      Darlene, thank you for reading. Yes there is something about a river that reaches deep inside us. Thank you for reading and for leaving your usual kind comment.

      PeggyW-Because crayfish are very prone to pollution{ or our native species is} they are used as a biodiversity indicator. Thank you for your appreciated comments.

      Sage Williams-thank you for taking the time to read and to make your encouraging comment.

      lelanew55, nice to meet you. Thank you for your comment.

    • lelanew55 profile image


      9 years ago

      I also love this hub and love rivers. I hope everything in that river will go back into its natural balance again. I read this in hurry. I will come back reread it again. There is a lot to learn. Thank you so much for sharing

    • Sage Williams profile image

      Sage Williams 

      9 years ago

      I just love the way that you wrote this hub. Your words are just so beautiful. The information that you provided was very interesting. I learned a lot.

      Great Job!


    • Peggy W profile image

      Peggy Woods 

      9 years ago from Houston, Texas

      Enjoyed reading this hub. Beautiful photos. Flyfishing is so beautiful to watch. I did not realize that crayfish are a sort of barometer as to the health of a river. Thanks for this information.

    • Darlene Sabella profile image

      Darlene Sabella 

      9 years ago from Hello, my name is Toast and Jam, I live in the forest with my dog named Sam ...

      Love this hub, I can sit and watch a river flow for hours, their is a poem about river being like life, sometimes it's still and calm, while at other times it's rushing, then it turns and changes course, like I always said, let's go with the flow and see where it takes us.


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