please people make sure your definatly taking only the signal (american) crayfish and not the UK native white clawed crayfish, if you are in any doubt as to how to identify between then, leave them alone and dont fiddle with them, as its considerbaly more of an offense to take out native ones without the relevent Natural England Licenses as they are a protected species, and in some cases they arent very easy to tell apart.
Also the trap in the first pic doesnt appear to have its EA trapping license tag attached to it, i assume you removed this after taking it out the water,
sorry to sound all anal about this, but the main reason for the decline in the native ones is people moving the signals about as food, which is why trapping licenses arent given out easily, also in most cases stone turning is quicker than trapping and doesnt require a license if your removing for eating (as long as they arent natives)
it prevents things like this happening:
http://www.environment-agency.gov.uk/news/118057.aspx