Saw crayfish the other day - are they the American or the British ones?
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Going by the large claws and smooth-looking carapace I'd say Signal Crayfish (non-native). This page may help with ID: www.boxvalley.co.uk/.../crayfish.asp
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Yes, that's a signal crayfish, an American species that has colonised many of our rivers to the detriment of the native white-clawed crayfish. We have not recorded the latter at Fowlmere since 1999. You should be able to find lots of info on the web.
We saw a signal crayfish this afternoon at Fowlmere (17/11/13). Other than letting people here know, does anyone know if they are so dangerous I should be letting anyone else know? Environment agency etc? If I'd known at the time it was a bad 'un I'd have tried to catch the little blighter.
I'm afraid we are resigned to their presence now. There was a time when they were restricted to the river downstream of the weir by the road, but now they have got past that they are here to stay. I saw a baby one once during a ForShep pond dipping session in Shepreth. It was perfectly formed but only about 1cm long, quite exquisite in fact, and it was obvious how they manage to escape from breeding sites if there is a leak.
Hey ho, next time I'll bring a net & a camping stove!
Just a couple of additional points come to mind. 1) Their only redeeming feature of which I am aware is that otters eat them. 2) I assume you're joking about the net, but it raises a serious point - biosecurity is really important. Therefore disinfect any equipment including wellies/waders BEFORE USE IN ANY WATER BODY. An outbreak of crayfish plague is what exterminated our white-clawed crayfish!
Hey doggie, that is not at all helpful! Crayfish poachers rarely care for where they are going and therefore don't clean their kit, and at least two otters have drowned in illegal crayfish traps in the Cam to my knowledge.
Oh dear, I didn't mean to cause an issue!
Yes! I was joking! I'm aware if the problems in catching the wrong one for a start! Not to mention the issue of infection. Sorry to upset everyone!
I've seen the kingfishers eat them also...............so another redeeming feature! :)
I hadn't realised kingfishers ate them, but I've just had a look in BWP and crustaceans are an accepted part of their diet. In a Spanish study cited therein, crayfish formed 10.4% (by weight) of the prey.