You have got to be careful, regarding the amount of freshly caught crayfish that you eat.
They do carry some nasty bacteria in their gut which can be dangerous to humans.
I tend to take between 40 and 50 live Crayfish a week for the table. A tip that I picked up a few years back, was to keep the live crayfish in a well aerated aquarium for a week. Feeding them only potato peelings. The peelings contain a chemical that flushes their gut out and kills the bacteria.
Another tip that I picked up, was to add a flavouring to the water that they are kept in. This has the effect of marinating them while they are still alive. I know that last sentence is going open me up to ridicule, disbelief, and other such things. So here goes.
For the 5 days that we have the Crayfish in the aquarium before we kill, cook and eat them.
Each day, I add a level teaspoon of either Schwartz Montreal steak, or Schwartz Garlic bread seasoning to the aquarium water. This has the effect of flavouring both the water that they are in, and the potato peelings that they are eating. No doubt, being the scavengers that the are, they are also picking up the small pieces of the seasoning and eating that to. It would not surprise me at all, if the seasoned water that is passing over their gills is also helping to flavour them up.
To kill them, I drop them into boiling water, and when I am certain they are dead. I wrap them singularly in tin foil and cook them under the grill or on the BBQ for about 15 minutes each.
To eat them just separate the tails from the body and shell them like you would a prawn, but be careful the shells are rock hard and sharp. Don't forget to crack the claws with a nut cracker and eat that flesh to.
