Crayfish trapping

[Tigerrr]

Someone I know has just bought a couple of crayfish traps and on first outing caught about 50 American monsters in the upper Thames.  He put them into the showertray overnight to clean them but most  appeared to die, so he musat have been doing something wrong. Do they need to rest in fresh water for 24 hrs at all?
Any crayfish experts here? I have already told him it is illegal to trap them etc. so we don't need to go through that.   

[bikenerd]

I don't think it's illegal to trap the American ones but it is illegal to trap the British ones.  You need a license from the Environment Agency to trap the American ones.

Environment Agency crayfish trapping rules

Once you've got them, leave them in a bucket of cool clean water for 24 hours, in the garage is a good place as the water won't be as warm as if you'd left it in the house.  This is just to filter the silt and mud out of them so they taste better, you won't die if you give them a quick swill in the sink then cook them.

[PaulR]

I've never had problems with survival of alien crayfish - quite the reverse in fact.  I can imagine a severe change of temperature might kill them off, or lack of oxygen if they're overcrowded and the water was not being refreshed through the night.

I think I'd want them to have plenty of fresh water before cooking them, depending on where they were trapped (I've only ever taken them from gloopy stillwaters and perhaps a clear free-flowing upper Thames is OK).

I had no idea it was illegal to trap them.  I thought it was positively encouraged. There was a chap some years ago (I don't know if he's still around) who used to trap them in the Serpentine and serve them up in his cafe on the Edgware Road.

[Regulator]

It is not illegal to trap American Signal Crayfish if you have a license, which is easy to get from the Environment Agency - as PaulR says trapping them is positively encouraged and the license is more about ensuring that you know the basic rules.  It is, however, illegal to release them once trapped.

More details available here

[numbnuts]

I was going to have a go at crayfish trapping, but my two local rivers Itchen and the Test don't have any in them 

[Bledlow]

There's a fishmonger in Reading (Frosts) selling crayfish, advertised as from the river Kennet. Looked pretty tasty. There's an opening for the entrepreneurial: find an outlet, & start flogging 'em.

[Zoidburg]

I keep seeing fisherman pulling signal crayfish from the canal instead of fish.

If they are in the canal system I can't see the chances of arresting their spread across English waterways.

[Tigerrr]

The trapping issue is that people trap a load of them,  take them home or along the river and then release them because they have too many etc - adding to the spreading. Also if you trap in one place your trap is infected with their virus which you va=can then drop into water full of natives upstream and kill them.
The haul from the Thames exceeded my wildest expectations - with 2 traps I had dinner for 3 people in an hour. Some of the buggers were huge and quite frightening with claws like half sized lobsters.

[ludwig]

When I was a kid we used to trap the native ones and eat them (70's) They were delicious. I've not seen either wild for years . I would imagine that there are farms in the UK for the nasty American ones.

[Tigerrr]

Actually the native is fast going the way of the red squirrel due to the aggression of  American Signal, and its killer virus. The local version which is small and shy is no match.  Given how many I caught I can only imagine that the bottom of the Thames where I was is simply crawling with them - like locusts.  I imagine that their population explodes until they eliminate the local food source and then they die back to a 'sustained' level - in a riverbed desert.

[rogerzilla]

In the 80s we had the Proper British sort in our local chalk stream.  You wouldn't have needed to clean those in fresh water.