1. To carry out mackerel egg survey (ICES Triennial Survey), on the western shelf and shelf edge in the area from 50N to 60N and 4W to 20W.
2. To collect fish samples, by trawling, for atresia and fecundity analysis back at the laboratory.
The vessel will proceed to the first plankton station line at 58 45'N 3o45W. Plankton stations will be taken westwards along the line 58 45'N at 30' intervals. Subsequent transects will be at 1oN intervals with stations at 30' E/W intervals. Plankton stations will be taken using the Gulf VII sampler with mounted CTD which will record salinity and temperature during the tow. The plankton tows will require the vessel to deploy and tow the sampler at 4-5 knots. The sampler will be lowered at a steady rate (10m/min) to within 5 m of the seabed or 200 m - whichever is shallower. The sampler will then be recovered at the same speed. Once aboard, plankton samples will be washed from the sampler net, fixed in formalin and scored for egg abundance. Trawl samples will be taken at the discretion of the scientist in charge. There should be a maximum of 15 trawls for the whole survey. The precise length of each transect cannot be defined in advance as this survey uses an adaptive design, where sampling along a line will continue until there are no or very small numbers of eggs.
The half landing is expected to be in Ireland around 17 June and likely to be either Galway or Cork depending on the progress of the survey. Due to the adaptive design of the survey and the extremely large area to be covered, the survey plan cannot be finalised in advance, rather it will be dictated according to the results that are recorded as the survey proceeds.
Normal contact will be retained with the laboratory throughout and with other vessels taking part in the survey.
James Drewery (Marine Scotland Aberdeen Marine Laboratory)
ICES Triennial Survey
International Council for the Exploration of the Sea (ICES)