den, I see you have posted a few times on this so sorry if I repeat stuff. I spent quite a long time looking at these. A GREAT and underrated wild food source IMO.
I brought a Crayfish trap last year and am about to go out and use it and will post results. Also I intend to trial various techniques for catching them more suitable for Bushcrafting (i.e. light and foldable traps etc.). They taste superb, are easy to cook and you also help to reduce numbers of the invasive American Signal Crayfish which is wiping out the native Crayfish both in the UK and France ( and other countries in Europe).
But be aware that it is illegal at present in the UK to trap Crayfish without a licence from the Environment Agency! Mostly a reaction to this serious problem and the need to ensure they are not transported alive to other waters which do not have them yet. Serious fines if caught.
Here in France sense reigns and as long as you stick to the 2-3 invading species you can catch all year round what you want. BUT you have to kill them as you catch them and serious fines for moving them even to home to cook. But for out in the wild a great natural resource. In some areas of Britain already infested you can check the postcode where you live with the EA and may or may not be able to keep them alive at home for personal consumption without a licence.
You can check out current proposals and byelaws on crayfish fishing at the EA:
http://www.environment-agency.gov.uk/subjects/fish/246986/257916/261125/?version=1?=_e
A couple of sites I would recommend to learn more about this, what baits work best, what shapes, sizes etc.
http://www.terrybullard.com/CrawfishMain.html
Lots of information. He makes traps to order based on years of crayfish trapping. Only available in the USA
but read the 'History' section for a fascinating account of his trapping and trap evolution. Also the Q&A section has lots of useful info. There are loads of photos of types of traps to look at.
http://www.trapperarne.com/index.html
Trapper Arnes crayfish site is more lighthearted look at crayfish but very useful too and more traps. Again it is in the USA but gives some good ideas of what to go for. The blue Swedish trap he sells is available in Europe.
Buying Traps in UK
http://www.alanaecology.com/acatalog/Crayfish_Traps.html
Alana Ecology in the UK sell two types. One is too small for the American Signal crayfish you want. The 'Trappy' trap with 20mm mesh allows the smaller native to escape but retain the larger Signal. £15.95 inc. VAT.
You can get more substantial ones here:
http://www.trap-man.com/trapmanstore/qd000000.html
Small Live catch Crayfish trap
Manufactured from 14g wire which is hot dipped in moulten zinc after manufacture for long life.
Dimensions 23"x7"x6"
Designed to only catch larger american signal cray fish
Hinged door to release captured crayfish
£*19.99**(23.49 Including VAT)
I ended up buying one from a store in Scotland.
http://www.solwayfeeders.com/ProductsDetail1.asp?STOCK_CODE=2011
Stock code: 2011 - Cylindrical Crayfish Trap
Price (incl VAT): £ 15.28
These 'trappy' traps are supplied flat and are easy to assemble. The advantage is they are tough but light and foldable. The cylindrical traps are apparently the best shape ( less snagging in bottom etc.) It also has a small cage you put the bait which is put in the trap. This stops the crayfish eating the bait and leaving so quickly!
Crayfish Trap for Free!
Found this guide to making a fish/ crayfish trap out of a plastic bottle. The instructions are in French but it is well illustrated with good photos of each stage.
http://jmsnat.free.fr/site/piegeetnasse.html
the section at the bottom refers to a mirror trap of sorts :shock: Apparently the fish see their reflection and attack it being lured into the trap. Not essential in the trap
I would probably look to get a larger bottle or container as signals are pretty big. Obviously there is no mesh to allow the smaller white-claw crayfish to escape so you would need to check when emptying.
It would make a good minnow/ fish fry trap too.
I posted some more detail on another thread here also:
http://www.bushcraftuk.net/community/showpost.php?p=34803&postcount=49
Happy trapping
Simon