RV Cefas Endeavour 17/08
Cruise summary report
|Ship name (ship code)||RV Cefas Endeavour (74E9)|
|Cruise period||2008-09-18 — 2008-09-25|
|Port of departure||Lowestoft, United Kingdom|
|Port of return||Lowestoft, United Kingdom|
1. To conduct a standard underwater TV survey of Nephrops burrow densities on the Farn Deeps grounds, 55 35 - 54 45 N and 1 30 - 0 40 W, and to evaluate Nephrops abundance for comparison with previous years.
2. To collect concurrent video data, using a second camera, which will be directly comparable with that collected from other Nephrops grounds.
3. To characterise sediment features at and between TV survey stations using a remote acoustic seabed discrimination system (swathe bathymetry and QTC).
CEFAS ENDEAVOUR sailed from Lowestoft at around high tide at 1100h local time on 18 September. In fine weather, the ENDEAVOUR made good progress up to the Farn Deeps. We were at our first station at the North Eastern corner of the grid at first light on the 19 September. The first station, at 0615h, was relatively shallow and was to be used to fine-tune the sledge and camera set up. Although the station had to be abandoned because of poor visibility, we were still able to sort out some of the tuning. Electronic interference from the cabling to the second camera was fixed but it was also apparent that due to the size of the new sledge it was not going to be possible to provide sufficient light for both cameras. It was decided to postpone the second aim of collecting data from two cameras until the first aim was complete. We moved west to another station but it was not until we had moved on to a fourth station, at 1200h, that there was sufficient clarity to record our first transect. We then worked round the clock picking our way from one station to another, zigzagging southwards down the survey grid. For the first three days of the survey, the weather was flat calm. It deteriorated for 36 hours of strong North Easterly winds and large swell that did eventually fine away. Despite the change in weather, the survey continued uninterrupted except for minor adjustments to our route to avoid fishing activity. The survey grid was completed at 2245h on the 23 September at the southern end of the grid. The priority was then given to repeating 12 stations where video recordings had been poor because of the weather or fishing vessel activity. It was decided to start at the most northerly of these stations. The 4-hour steam provided sufficient time to remount the second camera and rig some temporary lighting. These stations were used to meet the second aim of the survey by providing the concurrent video data. The re-runs were successfully completing at 1900h and after the sledge and the second camera was calibrated, CEFAS ENDEAVOUR set a course for Lowestoft at 2045h.
|Chief scientist||Jonathon Mark Elson (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory)|
|Cruise programme||(0.03 MB)|
|Cruise report||(0.55 MB)|
|Specific||Off NE English coast|
|Track charts||(0.03 MB)|