I do not get sea angling these days as frequently as I used to but when I did go, several times a month at one stage of my life, I used to fish for a wide variety of species, from mackerel, to pollock, to conger eel. I used to fish both from the shore and the boat but there was one particular species of fish I always used to love to see materialising from the murky and unknown depths and that was the big Winter cod. I cannot define why this was the one species which always gave me the biggest thrill to catch, perhaps simply because I enjoy eating it so much, but I devoted a lot of time to experimenting with different lures, rigs and baits in an attempt to maximise my catch of cod and codling.
I will begin with and I'm afraid effectively dismiss the variety of artificial cod baits and lures which are available to buy on the market today. I recall buying such as large white cod feathers and hokeyes at considerable expense on occasion but while I am well aware of the success such items can bring with other species, the only time I ever recall catching cod with them was when I also baited each hook with some fresh bait.
I would probably go for Pacific calamari squid as the most successful bait I ever used for cod. Although these particular squid were not native to any waters I ever fished they seemed to be a powerful attractant to cod, perhaps for this very reason in that they were something out of the ordinary. They are readily available to purchase, frozen in block form, from larger fishing tackle shops and even Oriental supermarkets, though in the latter instance the price is likely to prove prohibitive for fishing bait. Simply allow them to defrost when you get to the shore or on to the boat and pull one at a time from the block. They can be used whole for big cod baits or cut up in to smaller pieces for such as codling.
Lug worms are another excellent bait for cod. These big, juicy worms can be purchased live from many coastal tackle shops or frozen on a much wider basis. Be careful putting them on the hook as they can be full of a lot of water and splash an unsuspecting angler in the eye with same when we pierce them. A cocktail of calamari and lug worm can prove deadly when fishing for cod.
Rag worms would not be one of my first choices as bait when fishing for cod. They are extremely useful for a number of species and although I have known cod to go for them, I would rate them far below calamari and lug worms. Be careful when handling rag worms as they "bite" with the two pincers we can see protruding from their mouths and the larger ones are capable of giving us a nasty shock.
We can of course experiment with other baits for cod, depending upon what we have available to us and may know some success with such as fresh strips of mackerel or herring, or even razor fish or shellfish. There are no specific rules and a hungry cod will perhaps take any oily and strong smelling "food" offered it.