Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Tridens II	North Sea Herring Ac	27.06.2016 - 22.07.2016	NHAS	North Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Fassler Sascha	IMARES, Wageningen UR, Institute for Marine Resources and Ecosystem Studies, Texel	Scheveningen	Scheveningen

Ziel der Reise / Objectives of Cruise:

The objective was to carry out an hydro acoustic survey defining the abundance of herring and sprat in the North Sea, in co-operation with the institutes of Norway, Scotland, Denmark, and Germany. The first week of the whole 4 week survey period was used for calibration of the acoustic equipment in a sheltered location in Scapa Flow, Scotland. After the calibration at Scapa Flow The weekend was spend in Aberdeen. Departure for the survey Monday 4 July at 11:45 UTC, a bit later than planned, due to in and out going traffic in the port of Aberdeen. During the first week a lot of herring was encountered on the first five transects (58? 21'N, 58? 06'N, 57? 51'N, 57? 36'N, 57? 17'N; the last one is only 10 nmi). Only in the western and eastern outer ends there was no herring. On Saturday morning 10:00 Dutch time, we arrived in the port of Aberdeen. In the night from Sunday 10 to Monday 11 July Tridens suffered from some serious technical problems which caused us to stay another one and a half day in port. Technicians flew in on Sunday to solve the trouble. The damage was repaired and we leaved port at 14:00 Dutch time;12:00 UTC. To gain back the lost time it was decided to skip the following weekend and keep on surveying. On Saturday 16 July after waypoint 20 (56? 47'N-2? 06'W) Sascha Fassler and Andre Dijkman left the vessel by means of a tender to fly to IJmuiden. After this break, we headed for the next waypoint: 56.17N-2.26W. The remaining transect were surveyed swiftly in southern direction. On these transects we recorded some sprot concentrations. No adult herring. We entered the port of Scheveningen on Thursday evening 18:00 NL time. Since 2010, cruise leaders keep a weblog during the survey, which can be found at: http://herringsurvey.blogspot.nl

Messungen / Measurements