Colder waters produce fish with more fat.

Re: Scallops and really all fish

There is no difference between fresh and properly frozen fish. I catch and eat fish here on Cape Cod and freeze them to consume later. Bluefish, black seabass, scup, tautog. All of them taste exactly the same if frozen immediately after gutting and filleting. I freeze them in ziplocs with as much air removed as possible. Same goes for scallops. We buy 1-3 lbs of fresh scallops a week from some friends that run a boat here and freeze a lb or two every other week. They keep perfectly and we've eaten them as sashimi/sushi after defrosting more than once.

I have to disagree on the diversity of fish on West vs East coasts. The diversity of fish in the supermarket may be different but the west coast has a slightly larger variety of easily catchable eating fish. Rockfish (3 or more varieties), drum, striped bass, salmon, lingcod, surfperch, greenlings, cabezon, halibut, sheephead and yellowtail tuna are all fishable.. Here on the Cape we have striped bass, bluefish, tautog, black seabass, scup, haddock, pollock, cod, flounder/sole (rarely), dogfish (very rarely). Bluefin tuna are also fishable but I don't consider those a target species for most people due to the cost.

One of the current problems with climate change out here is that we're now getting some very rarely seen fish (Bonefish, triggerfish, mahi) that show up en masse every year. While fun for fishing, they are eating the feeder fish that sustain our local biomass.