Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Tridens II	HERAS 2010	28.06.2010 - 23.07.2010		North Sea

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

Ziel der Reise / Objectives of Cruise:

After departure on Monday 28th June from the port of Scheveningen, Tridens steamed north in the direction of Scapa Flow. On 29th June at 56?25'N-0?35'E a test haul was carried out. Due to the extremely good weather conditions, it was decided to try to calibrate at sea. The calibration was carried out close to the starting point of the survey (58?23'N-2?44'W) in the afternoon of 29th and the morning of 30th June. The actual survey started 8:51 UTC on the 30th of June 2010. During the remaining days up till the weekend stop in Peterhead, 6 hauls were carried out. A lot of small schools at the surface were seen in the area. Unfortunately, on two occasions the crew claimed that it was not possible to fish on the recordings due to technical problems (once because of a not working netsonde and once because the vessel had only on engine available). Hence important information on school composition was lost. The survey was interrupted at 57?50'N - 1?40'W at 11:05 UTC for the stop at Peterhead. Departure from Peterhead was delayed by one hour in the morning of 5th July on instruction of the harbour authorities. The survey continued according to the planned transects till Thursday 8th July at 56?50'N - 1?50'E. Arrival in Scheveningen the next morning at 6:00 UTC. Departure from Scheveningen on Monday 12th July was delayed by 6 hours due to technical problems concerning navigation lights of the ship. After these problems were solved, Tridens steamed up north-west to the start point of transect line 6 (56?20'N-2?27'W). The survey was started the following day, Tuesday 13th July at 16:20 UTC. During week 28 no hauls were carried out as major fish aggregations were absent on the echosounder records. The weather situation turned to the worse towards the end of the week and gale force winds (8 or even 9) were experienced. While there were fish seen at that time, no trawls could be done due to the bad weather conditions. Also, 2 CTD stations had to be abandoned for bad weather reasons. On Friday morning 16th July at 7:42 UTC, it was noted that the network connection to the acoustic room was lost. An investigation identified the cable socket in the network hub in the ships computer room to be faulty - most probably caused by increased movement during bad weather. To solve the problem, the cable was rewired to a connector and provisionally connected to the acoustic room. The fault caused that the echosounder data had no GPS position signal for over 4 hours. The lost position data was interpolated during data analysis. Additionally, a security steal cable going to the towed body was found to be cut apart due to increased grinding on the towed body itself during heavy winds. The survey was stopped on Friday 16th July at 15:45 UTC, after the end of transect 7 (55?05'N-1?33'W) was reached and Tridens steamed to Newcastle-upon-Tyne for the week end break. Departure from Newcastle was on Monday morning, 19th July at 6:00 UTC. The survey continued on the same day at 9:50 UTC at the start of an additional transect (55?35'N-1?18'W), which was added at latitude 55?35'N between 1?18'W and 1?50'E. This was done in an attempt to collect biological/hydrographic information in rectangles where no trawling/CTD could be performed due to the bad weather in the previous week. As enough time was available, this did not affect the original coverage. The remaining transects were covered as planned until Thursday 22nd July at 54?20'N-0?8.8'W. ETA in Scheveningen was on Friday 23rd July at 5:00 UTC.

Messungen / Measurements