An acoustic survey targeting blue whiting (Micromesistius poutassou) spawning and post spawning aggregations in the north east Atlantic in 2008.

Spawning takes place from January through to April along the shelf edge from the southern Porcupine Bank area northwards to the Faroe/Shetland Ridge including offshore areas as the Rosemary, Hatton and Rockall Banks. Peak spawning occurs between mid-March and mid April and acoustic surveys are timed to occur during this phase.

The 2008 survey was part of an International collaborative survey using the vessels RV Celtic Explorer (Ireland), RV Fridtjof Nansen (Russia), RV Tridens (Netherlands) and the RV Magnus Heinason (Faroes) and the FV Gardar (Norwegian commercial charter).

This survey covered the primary core spawning area of blue whiting to the west of the Ireland and the Western Isles. The survey track commenced off the west coast of Ireland at the shelf break and progressed northwards to the Hebrides. Westward extension reached the eastern flanks of the Rockall Bank.

A parallel transect design was adopted with transects running perpendicular to the lines of bathymetry where possible. Acoustic data were collected using the Simrad ER60 scientific echosounder.

Biological sampling was done using a single pelagic midwater trawl.Fish samples were divided into species composition by weight. Species other than the blue whiting were weighed as a component of the catch. Measurements of blue whiting lengths were recorded. Age, length, weight, sex, maturity and stomach fullness data were recorded.

A visual survey for marine mammals and seabirds was conducted during daylight hours.

Oceanographic data on temperature, depth and salinity (CTD) were collected at set stations.