A second step in utilizing Great Britain's natural resources began long ago when people first caught fish. Its main development dates from 1416 onward. Previous to that time the drowned coast and many harbors of the island had been an asset of relatively small value. In that year, perhaps because of a change in oceanic salinity or temperature, the shoals of herring which had previously been found chiefly in the so-called Sound at the western end of the Baltic Sea, suddenly appeared in the North Sea off the coast of England. This fact co-operated with improvements in boats and tackle and increasing pressure of population in leading the British who lived around the drowned harbors of the east coast to develop fisheries on a large scale.
The North Sea, the harbors, and most of the kinds of fish that are now caught had been there for a long time, but only then did the British reach the point where they were ready to utilize these new resources on a large scale. The development of the fisheries led in turn to a rapid evolution of overseas trade. As the fishermen went farther afield after fish they acquired skill and boldness. Then they found it profitable to carry more goods than formerly across to the mainland. So ports began to grow rich through commerce with the continent.
Today, Great Britain is responsible for half of the total catch of fish in the northern waters of the Atlantic, as well as for a catch of smaller importance along the south coast where sardines are taken. Codfish, haddock, and herring are the principal fish caught in the North Sea and around the Shetlands, Orkneys, and Hebrides. Kirkwall in the Orkney Islands, and Lerwick in the Shetland Islands, like the Norwegian coastal towns, are busy places in the fishing season. Wick in the far north of Scotland, and Peterhead and Aberdeen farther south, as well as Grimsby and Yarmouth in England, are the main harbors which ship fish to the regions of consumption.