CE0906 Celtic Explorer North-West Blue Whiting (Micromesistius poutassou) Acoustic Survey Ireland 2009

Westward extension reached the western flanks of the Rockall Bank. The survey was carried out in continuity from south to north with no scheduled or unforeseen disruptions. The 2009 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 Brennholm (Norwegian commercial charter).

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. Cruising speed was maintained at a maximum of 10 Kts (knots) where possible.

Biological sampling was done using a single pelagic midwater trawl. All components of the catch from the trawl hauls were sorted and weighed; fish and other taxa were identified to species level. Age, length, weight, sex, stomach fullness and maturity data were recorded for individual blue whiting within a random 50 fish sample from each trawl haul with a further 100 random length and weight measurements were also taken.

All blue whiting were aged onboard. Oceanographic data on temperature, depth and salinity (CTD) were collected at set stations. 1. Collect acoustic data on blue whiting spawning aggregations s of blue whiting (Micromesistius poutassou) along the northern migration pathway 2.

Collect biological samples from directed trawling on fish echotraces to determine age structure and maturity state of survey stock 3. Collect CTD data