Vacuum pack fresh, thaw out the day before you go and coat them in rock salt to cure over night before you fish. If you leave them in the salt they will shrivel up so try not to leave them in there for too terribly long.

Another option would be to pickle them whole in a jug. That would probably be the best, but stinkiest, messiest, and most space consuming option. Find a pickling recipe online specifically for dinos, lots of people pickle squid in this manner. Once they are pickled you can just leave them in the fridge pretty much indefinitely AND they stink to high heaven..... use gloves when handling.


I personally would just do the vac pack then salt technique.
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When I grow up I want to be,
One of the harvesters of the sea.
I think before my days are done,
I want to be a fisherman.