Last Saturday I found myself in the local supermarket browsing for dinner. In the seafood section I spied a slim package with two pieces of plaice in it, a kind of flatfish rather like flounder. Each was little bigger than a dollar bill and weighed just four and a half ounces. What struck me about this package was a label that proclaimed they were ‘large' fish. The fillets in the packet could not have come from an animal more than 10 inches long. Moreover, these fish were certainly immature and had never had a chance to breed. But they were legal to sell. Some years ago, if I recall correctly, the French Fishery Minister persuaded fellow nations in the European Union that the capture of juvenile plaice should be allowed because French consumers demanded fish small enough to fit their plates. The fortunes of plaice have been transformed over the last 200 years. In the 19th century they were shunned by well-to-do customers as ‘offal' fish; good only for the poor. They gained favour in the early 20th century as the new steam powered draggers brought record catches ashore that found a ready market in inland towns and cities. A hundred years ago, a large plaice was a grand beast. A fish had to be 20 to 24 inches long and weigh three to four pounds to be considered big. At that time, grizzled old timers of 32 to 40 inches long were still sometimes caught. I doubt such a fish has been taken from the North Sea in the last half century. My encounter with the supermarket plaice neatly illustrates the phenomenon of shifting baselines, changes in the way we perceive the world. Over time, intensive fishing has reduced numbers of big, old, fat fish. What would in 1900 have been almost too small to bother with is now all that is on offer, and to us seem large. The loss of big fish, while convenient for supermarket traders who like plate-size fillets, is bad news for the survival of fish in the wild. Landings of plaice into England have fallen by 96% since 1900 as stocks have crashed. And there is little prospect of recovery while most fish get taken before they have a chance to reproduce. Big fish produce many times more offspring than small ones so they are vital to sustaining healthy populations in the sea. If commercial fish like plaice are to have a future, we must create refuges in the oceans where big old fish can live long and productive lives. Their young will help fisheries prosper once more in the rest of the sea. ———- Callum Roberts is Professor of Marine Conservation at the University of York in England and the author of The Unnatural History of the Sea. Click here to visit his website.