Rare crayfish found in Leeds beck

Tinkerbell · #1 (**permalink**) 20-01-2006, 03:29 PM

Found in Meanwood Beck at Sheepscar, Leeds this week - Britain's only native crayfish (freshwater white-clawed). Apparently one of these rare crustaceans was carrying a number of eggs, and this very important find of several creatures tends to indicate that the beck and nearby rivers are becoming cleaner. Sewage overflows into the beck have been cleaned to enhance and extend the crayfish habitat.

pheonix · #2 (**permalink**) 20-01-2006, 04:16 PM

have you got a source for this information?

Tinkerbell · #3 (**permalink**) 20-01-2006, 05:17 PM

Certainly - http://www.bbc.co.uk/leeds/features/index.shtml - Crayfish come to town.

Fourwings · #4 (**permalink**) 20-01-2006, 07:39 PM

It's nice to see somewhere that our native species is doing well.

In this area it has been all but eradicated by the dreaded American Signal Crayfish, our local brook is absolutely infested with these monsters, they resemble small lobsters,some reach several inches long & have a real bad attitude problem when caught!

This same brook used to be home to the native species, once the "signals" arrived they were wiped out in months - a real tragedy

pheonix · #5 (**permalink**) 21-01-2006, 03:36 PM

thank you, one of my collegue is interested as he is really into freshwater ecology and has just got his crayfish licence.

thanks

Tinkerbell · #6 (**permalink**) 21-01-2006, 03:47 PM

Are the American Signals of no use as shellfish to the restaurant industry? If they are to be found in large numbers sometimes, and are edible, I wonder if they are netted for this purpose.

Fourwings · #7 (**permalink**) 22-01-2006, 07:26 PM

Quote:

Originally Posted by Tinkerbell

Are the American Signals of no use as shellfish to the restaurant industry? If they are to be found in large numbers sometimes, and are edible, I wonder if they are netted for this purpose.

The Signal crayfish is edible & somewhat of a delicacy or so I'm told.
I am reliably informed that most of the infestations of this species were caused by the accidental release/escape of Signals that were being farmed for the table, this was certainly the case in our area.

As far as I am aware there are laws prohibiting the capure & removal of this species from infested watercourses, this is pressumably to guard against further infestations taking place.
The enviroment agency were until recently carrying out an extensive trapping program on our local brook in a bid to halt the Signals progress downstream towards the main river system, this was suspended because it was not having any impact on the numbers, it seems once they are in a watercourse they are almost impossible to get rid of, containment seems the only answer but this doesn't help the plight of our native crayfish species

henrya · #8 (**permalink**) 23-01-2006, 06:28 AM

The main problem with Signals, apart from the fact that being bigger they will probably win any competition, is that they carry the fungus Aphanomyces astaci, which, though not affecting the Signals very much, is deadly to native crayfish.

henrya

kerfoot · #9 (**permalink**) 23-01-2006, 07:20 AM

Hello, I'm lucky enough to live just a minute away from the beck as it flows at the bottom of my road. During a masters course I did last year we went to the beck and were given a talk by a lady from english nature who is monitoring the population. We did find quite a few there and I think there are no signal crayfish in the beck yet-at least there weren't last year. The beck has been severly modified in places which probably makes dispersal more difficult for the white clawed crayfish. But its good to hear they are still there and hopefully expanding.

Perhaps someone with a license could answer a few questions I had. What are you meant to do if you capture signal crayfish whilst surveying for white clawed? Are you meant to kill them? And if so how? These things can spend weeks away from water so would have to be proporly dealt with. Is it possible that the plague can be carried on wellies, nets etc. and transfered between water courses unintentionly?

I can confirm that signals are good to eat-I had a plate of them in france and they were fantastic! But I'm sure problems may arise if everybody started collecting them. Mistaken ID's, rerelease into different watercourses....

henrya · #10 (**permalink**) 23-01-2006, 07:42 AM

Quote
Is it possible that the plague can be carried on wellies, nets etc. and transfered between water courses unintentionly?
Endquote

It is possible that this may occur, or that spores may be transferred by birds, but it does not seem to have been proved.

Quote
I can confirm that signals are good to eat
Endquote

Native Crayfish are (or were, when they were commoner) also eaten.

henrya