Fish egg and larval surveys are carried out to map spawning grounds and to derive information on the adult spawning stock. Fisheries Science Services are part of an international consortium of eight European countries that run the international mackerel and horse mackerel egg surveys every three years.
Purpose of the survey
The aim of the international Mackerel and horse mackerel egg survey program is to estimate the spawning stock biomass (the total weight of all sexually mature fish in the population) of the North-east Atlantic mackerel and horse mackerel stocks. This data will feed into the stock assessment as fisheries independent information. In addition, the data provides important information on the timing and location of spawning for mackerel and horse mackerel. The survey has been running since 1977 and therefore provides important information about the distribution and timing of spawning in relation to climate change.
How is the survey carried out
The international mackerel and horse mackerel egg surveys take place every 3 years and cover the spawning grounds in the NE Atlantic from Portugal to the north of Scotland between February and the end of July. A plankton sampler called a GULF VII is deployed from the ship to collect plankton through a net of fine mesh size. Scientists count the number of recently spawned fish eggs and relate these to the eggs produced per female fish to obtain an estimate on the size of the spawning stock.
Results from recent mackerel egg surveys
In March and July 2007 the Marine Institute participated in the international mackerel and horse mackerel egg survey and covered stations in the Celtic Sea and West of Ireland. Download the survey reports from the March 2007 Mackerel Egg Survey (PDF, 468 KB) and July 2007 Mackerel Egg Survey (PDF, 331 KB)
To find out more about: Where fish eggs are found? How species are identified? etc.. please download 'Fish Egg & Larval Surveys' (1.1 Mb pdf).
Station Positions During the 2007 International Mackerel & Horse Mackerel Egg Survey
