The survey was part of an international hydroacoustic survey providing information on stock parameters of small pelagics (Acoustic Survey in the Skagerrak and Kattegat, the North Sea, West of Scotland and the Malin Shelf area, HERAS) coordinated by the ICES Working Group of International Pelagic Surveys (WGIPS). Denmark, Ireland, the Netherlands, Norway and Scotland also participated in the survey. In general, this survey provides the most important fisheries independent contribution to the assessment of herring stocks in the North Sea, Western Baltic Sea, Skagerrak/ Kattegat as well as areas west of Scotland and the Irish Sea. The total survey area largely covers ICES Divisions IIIa, IVa, IVb and VIa.
The survey design has been standardised across participants and the survey area is partitioned into 23 strata out of which four strata comprising the southern North Sea have been allocated to Germany and were covered during this survey. The main focus was herring (Clupea harengus) and sprat (Sprattus sprattus), whereas distribution patterns and abundance of anchovy (Engraulis encrasicolus) as well as pilchard (Sardina pilchardus) were another objective of the survey.
Altogether, 1508 nautical miles of hydroacoustic transects were covered, less than planned, due to adverse weather conditions throughout large parts of the survey that accordingly required adaptations to the cruise plan. One transect in Sl31 had to be omitted, another one significantly shortened to cover the survey area within the remaining survey time available.
Matthias Schaber (Thünen Institute of Sea Fisheries, Bremerhaven)