Signal Crayfish has become a plague in Britain

look at this stunning the yorkshire dales they call it God's own country and today you can see why it's fabulous this has to be the archetypal bubbling brook all of this fresh unpolluted rain water coming down off of the hill channeling down over these rocks making these riffles full of oxygen it should be absolutely teeming with life and it should be but very sadly I can tell you that it isn't because this burn is effectively ecologically dead I'm here with Paul Bradley an ecological consultant and an expert in the root of this problem the invasive American signal crayfish oh look at that now Paul for stream which is ecologically dead this is quite a large organism to be present and that is a mass of animals a huge biomass and we pulled that out of an area of a few square meters there's a massive number of these things in here well that's right this is just one night of trapping but really this is just a tip of the iceberg signal crayfish were first brought to the UK in 1976 as part of a commercial farming project but soon some escaped into our waters these crustaceans eat everything from invertebrates to fish plant matter and even other crayfish the invaders are large and aggressive and they breed fast but they're also carriers of a plague which kills our only native species of crayfish the white clawed crayfish who understand the magnitude of the problem here drastic measures are required so we've called in the Environment Agency and some of their heavy duty equipment spectacular if I can slow my feet we're going to drain the stream all right like sewing off the sunbirds isn't it we damned a small section of the stream and we're using a powerful pump to expose the rocky bed this is the only way that an ecologist like four can accurately count how many koi fish are in this stream so Paul we're now looking for those which were too small to be caught in the traps yeah that's right now we start to find just how many are here then though there we go there's one there's one straightaway that's about two years old that one but there are much smaller ones in there than that that's one just there yeah there's another one we're getting good at this Wow the live ones that people see in traps just a very very small proportion when we look very carefully in the stream we find up to up to 50 per square meter 50 50 per square meter in this very stream and we find them 30 centimeters into the gravel as well literally millions of signal provision Wow well fifty per square meter is almost and an infestation isn't it I don't like to use that word I've visited a stream every year since 2000 warden that's actually what I've seen an infestation in that time and all the fish have disappeared and the native white or crêpes are disappeared no fish at all with no fish at all now in the stream they've eaten all the eggs all of the yarn everything they seem to be the signal crayfish have consumed almost all other species in this stream and when they run out of prey they resort to cannibalism surviving on their own kind but this isn't just a local issue they've spread across the UK at an alarming rate from their introduction in Dorset they're now present in 80 percent of the rivers in England and Wales and they can be found as far north as Inverness Mark Owen from the angling trust is on the front line in the fight to slow this spread how these animals moving that's the key thing if you look at the footwear that we've got on today there's all sorts of little areas in it that you can pick up things accidentally which is why we're pushing check clean drive biosecurity slogan that all water users and pushing very hard language that they should be ensuring their equipment is properly checked cleans dried or they go to another water source and once they are in a water course are there any practical solutions in the pipeline we are working very closely with government scientists at sea fats on six pilot projects where we're looking at different trapping techniques losing anglers and as as the volunteers if you like to do these and the initial results about to really quite promising so there is some chance that Britain's angling army if you like might come to the rescue when it comes to eradicating their species I very much hope sir

Channel: 33Crazydude

Views: 1,069,962

Rating: 4.5161366 out of 5

Keywords: Signal Crayfish (Organism Classification), Plague, Crayfish (Food), Fish, invasive species, Conservatism (Political Ideology), Wildlife Conservation Society (Nonprofit Organization), white-clawed crayfish, River (Geographical Feature Category), Lake (Geographical Feature Category), Fresh Water Lake (Lake Type), Crustacean (Organism Classification), Pacifastacus leniusculus, Chris Packham (TV Personality), Environmentalism (Political Ideology), Stream (Geographical Feature Category)

Id: qImSSqYh298

Length: 5min 33sec (333 seconds)

Published: Thu Jan 22 2015