Mackerel and Horse mackerel egg surveys 1992 - present

Every three years the ICES Working Group on Mackerel and Horse Mackerel Egg Surveys (WGMEGS) coordinates a major survey in the northeast Atlantic. These surveys cover the northeast Atlantic between the Gulf of Cadiz and currently the south coasts of Iceland and Faroes, between January and July. The surveys were started in 1977 by France and England. While these countries no longer participate the surveys have expanded and are currently carried out by ten nations. The aim of the survey is to relate the number of freshly spawned eggs in the water column with the number of females having produced these eggs. Knowing the fecundity of the females and the sex ratio of the population allows for the provision of an estimate of the spawning-stock biomass (SSB) (ICES 2018). The survey collects positional and CTD data, as well as a plankton haul at every ICES half statistical rectangle. All fish eggs are extracted from the plankton samples. These eggs are subsequently identified and their stage of development noted. During the surveys opportunistic fishing hauls are also carried out, to collect histological samples from female mackerel and horse mackerel.