The egg production and spawning stock size of the North Sea mackerel and horse mackerel stocks in 1988

During the period 5 April to 28 July 1988 the spawning areas of North Sea mackerel and horse mackerel were investigated by research vessels from the Netherlands, Denmark and Norway. Based on the plankton samples and temperature observations obtained during this period the egg production and spawning stock size were estimated. The total egg production of mackerel represents a spawning stock biomass of 37 000 tonnes, which is about 20 % less than the 1986 estimate. The total egg production of horse mackerel represents a spawning stock size of 110 000 tonnes

The egg production and spawning stock size of the North Sea mackerel stock in 1990

During the period 12 March to 20 July 1990 the spawning area of the North Sea mackerel was investigated by research vessels from the Netherlands, Denmark and Norway. Based on the plankton samples and temperature observations obtained during this period the egg production and spawning stock size were estimated. The estimated total egg production of mackerel (53 x 10^12 eggs) represents a spawning stock biomass of 78 000 tonnes, which is about twice the estimate in 1988

The egg production and spawning stock size of the North Sea mackerel stock in 1984

During the period 22 May to 17 July the spawning area of North Sea mackerel was investigated by research vessels from Scotland, the Netherlands, Denmark and Norway. Based on the 629 plankton samples and temperature observations obtained during this period the egg production and spawning stock size were estimated