Evolution of the theory of rational fishing. The case study of the North Sea

Demersal fishing in the North Sea has a long and fairly well documented history. The Southern North Sea seems to be a biologically rich region in which all the coastal states around it have participated in the demersal fishing opportunities especially operating near coasts. However, the expansion to deeper, offshore waters in the 19th century was mostly by English fishers, with Scottish involvement in the more Northerly zone. The expansion was generated by the construction of railways and availability of manufactured ice, making it possible to provide fresh fish in good condition to the expanding population. Towards the end of the century, the entry of steam vessels caused further expansion and increase in fishing intensity. From the second half of the 19th century, it became apparent that this was changing the fish stocks. Annual catches did not increase in proportion to the increase in intensity, and the average sizes of fish in the catches declined. These events stimulated much discussion and research about how to manage these fisheries. This situation was strengthened by the establishment of the International Council for the Exploration of the Sea in 1902. After the World War II, the idea of managing to obtain Maximum Sustainable Yields by setting Total Allowable Catch limits gained hold worldwide. In the last few years, the EU has changed the target to limiting fishing intensity to some level less than would be needed to obtain MSY -a quantity which is still poorly and ambiguously defined. This 'less than' management policy has yet to be implemented, but if and when it is it will provide huge benefits to the economics of fishing but will also reduce the deleterious impact of industrialized fishing for target species by reducing unwanted incidental catches of other species and harm to the marine environment.