Tridens 06-015 2006

Cruise plan

Cruise Info. 
Ship name (ship code)Tridens (64T2)
Cruise identifier06-015 2006
Cruise period2006-06-26 — 2006-07-21
Port of departureIJmuiden, Netherlands
Port of returnScheveningen, Netherlands
ObjectivesDutch part of the international North Sea hydro acoustic survey for herring. The survey is coordinated by ICES and has been executed annually since 1991. Scotland, Germany, Denmark and Norway also participate in the survey. The purpose of the survey is to estimate the herring stock of the North Sea. The ICES Herring Assessment Working Group (HAWG) uses this estimation is as a "tuning index" to assess the North Sea herring stock. For this survey a Simrad 38kHz splitbeam transducer was used together with a Simrad EK60 echo sounder. The applied method was echo integration. By sailing transects over the survey area, the total acoustic cross-section can be calculated by surface area sampled. Trawling identified species composition of localized schools. The length composition of each species was determined. Herring and sprat were examined on age and fecundity from which a split up stock structure was made.
Chief scientistHenk J L Heessen (Netherlands Institute for Fisheries Research)
Coordinating bodyInternational Council for the Exploration of the Sea (ICES)
NPRCTridens 06-015 2006 NPRC tridens_20060626.pdf (0.08 MB) 
Ocean/sea areas 
GeneralNorth Sea
SpecificCentral North Sea