Clam bakes? Nope. I've heard of them in the US. I did a quick search and found some local tourist places that offer them, I would guess for travelers from the south. Lobster rolls galore (even in the past at MacDo's), and a lot of dishes with clams and scallops. I'm 3 km from a clam digging bay.
I've sat around while people from the north cut and ate fish with ulus, and eaten a lot of fish cakes. I haven't had pike chowder. That would have to be away from the populated areas as apex predators collect a lot of pollutants, and aren't favoured as food where I've lived.
There are a lot of vocabulary and some grammar differences between the various forms of English. A lot go with food. There are some food differences too. When I first watched the British Baking Show, I had to learn some vocab. I sometimes have to listen closely to relatives out on the west side of Canada. I love language differences and look for them, but I recently saw a guide to Canadian English for US visitors, produced in the west, and quite a few phrases meant nothing to me. My English has a lot of French words in it, and I always have to filter them out carefully when I travel.
I don't think the actual prawn/shrimp difference matters as here we have a question of usage. I'm going to roll with the idea that for an average British aquarist, a shrimp is a prawn is a shrimp.