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