An acoustic survey targeting blue whiting (Micromesistius poutassou) spawning and post spawning aggregations in the north east Atlantic in 2006.

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. To facilitate a more coordinated spatio-temporal approach to spawning stock assessment, several nations became involved in the ICES led Planning Group of Northern Pelagic Ecosystem Survey (PGNAPES) coordinated survey. Ireland is one of these nations involved in this annual survey.

The 2006 survey was part of an International collaborative survey coordinated by the Institute of Marine Research, Bergen, Norway, using the vessel the RV “G.O. Sars”. Also participating were the RV “Atlantniro” (Russia), RV “Tridens” (RIVO, Netherlands) the RV “Magnus Heinason” (Faroes) and RV “Celtic Explorer” (Ireland).

The survey area extended from the south Rockall Trough as the southern limit, west of the Rockall Bank, northerly extension reached to the Hatton Bank and the easterly extension to mid Rockall Trough.

An East-West and North-South transect design was employed. 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 taken. Age, weight, sex, maturity and stomach fullness data were also recorded. During daylight hours visual observations for marine mammals and seabirds were also conducted on the survey.

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