§ Mr. Andrew George
To ask the Minister of Agriculture, Fisheries and Food what assessment his Ministry has made of the reason for the decline in fishing stocks in the last three years by(a) stock and (b) area. 
§ Mr. Morley
[holding answer 21 December 1999]: Not all fish stocks have declined in the past few years. For example, the large western mackerel stock has increased since 1994, and the Norwegian spring-spawning herring has doubled in size over the same period and has also extended its distribution.
Most of the whitefish stocks however remain at or near historically low levels. This is associated with high levels of fishing mortality. In the North Sea, the recent assessments indicate some reduction of fishing mortality on roundfish, which will help to restore those stocks.
All fish stocks are subject to great variations in the numbers of young produced each year. This variation is caused by changes in the size of the mature adult stock and annual changes in the environment being more or less favourable to the survival of larval fish. So even though stocks may be at generally low levels good or bad recruitment of young fish will cause the stocks to increase or decrease over periods of a few years.
Against this background of variation, some sea areas have experienced a general warming. While this may be favourable for some stocks, such as sole, it has apparently adversely affected the production of young cod, especially in the North Sea and in the Irish Sea.