They never did, and never will. But herrings are a different matter, as those of you familiar with Ewan McColl's "silver darlings", know.
A recent Bagehot article in the Economist about fishing in the river Clyde (well, actually about no longer fishing in the Clyde) illustrated how timid politicians, a valourisation of tradition, and self-serving on a massive scale, all conspired to clean the Clyde, not of pollution, but of fish. It's a tale that would be cautionary, were it not so common as to be commonplace.
Not many fish, or much learning, around, as the ending of Bagehot's piece illustrates:
Fishing, for as long as anyone can remember, was more than an occupation in Carradale. The community was founded on it. Youths went to sea in their uncles’ boats, formed ring-netting pairs with their neighbours, married one another’s sisters and celebrated by drinking and singing songs about herring. Support for the fishermen was bolstered by a desire to preserve these happy traditions. But how misguided that was. Carradale is shrinking. Its young folk are leaving; one of the five boats is crewed by Latvians for want of local labour. “Last year was a bad year, 18 deaths and the rest of us ageing,” was how an old fisherman greeted Bagehot on his return to the village. Few sing about herring these days. Nobody sings about prawns.