RV Cefas Endeavour 10B/06
Cruise summary report
|Ship name (ship code)||RV Cefas Endeavour (74E9)|
|Cruise period||2006-04-26 — 2006-05-05|
|Port of departure||Lowestoft, United Kingdom|
|Port of return||Lowestoft, United Kingdom|
1. Analyse spatial and temporal variation in carbon and nitrogen stable isotope ratios close to the base of marine food chains (filter feeding infauna and zooplankton)
2. Investigate relationships between body size, energy content and trophic level (from nitrogen stable isotope analysis) in space and time for zooplankton, benthic invertebrate and fish communities
3. Study the relationships between body size and production for zooplankton, benthic invertebrate and fish communities
4. Collect solenette to estimate density and trophic level in the southern North Sea.
CEFAS ENDEAVOUR sailed from Lowestoft at 19.00h on Tuesday 25 April 2006. She steamed approximately 110 miles where an adrift wave rider was recovered at 53°55.73N, 02°48.32E at 06.15 on Wednesday 26 April. CEFAS ENDEAVOUR proceeded to the Silver Pit region of the central North Sea the same morning and work at the first three of five 'benthic ecology' station commenced at 08.19h. Seven replicate NIOZ cores were collected and sub-sampled for the analysis of sediment granulometry and stable isotopes, meiofauna, chlorophyll a and porosity. The remaining cores were then sieved to obtain benthic infauna for stable isotope and energetic analysis. Subsequently, two 2-m beam trawl collections were carried out at the same station. Catches of invertebrate epifauna were size fractionated for the analysis of spatial and temporal variation in carbon and nitrogen stable isotope ratios and this work was completed at 17.15h. Work at the first three of eight TTN zooplankton stations commenced at 18.50h. Samples were size fractionated at sea and sample collection and processing was completed at 24.00h.
On Thursday 27 April from 05.41h to 11.13h, 2-m beam trawling and NIOZ coring at the remaining two 'benthic ecology' stations was completed successfully. Work at the five remaining TTN zooplankton stations commenced at 11.51h and the final sample was collected at 18.41h. CEFAS ENDEAVOUR then steamed 56 miles to re-deploy the wave rider off Dowsing at 53°32'08N, 01°03'07E at 22.58.
On Friday 29 April, from 05.42h to 13.54h, two 4-m beam trawl tows were completed at each of the three 4-m beam stations. The fish caught on these tows were processed for stable isotope and energetic analysis. CEFAS ENDEAVOUR left the Silver Pit at 16.00h and steamed SE to a trawl line in the Indefatigable area (53°50.05N, 02°10.00E to 53°47.53N, 02°15.06E) where, as part of an ongoing study in this area, two 4-m beam trawl tows were collected commencing at 05.42h. Fish and bivalves from both tows were processed for stable isotope analysis. Subsequently, two 2-m beam trawl tows were conducted to collect samples of scaldfish, solenette and bivalves to complement 4-m beam trawl samples. As in previous cruises, bivalve catches were low and therefore a further five 2-m beam trawl samples were collected after fitting short lengths of chain to the shoes of the trawl.
With the planned work for the Indefatigable completed at 12.04h, CEFAS ENDEAVOUR sailed approximately 9 nm NW to commence a 2-m beam trawl survey in the area 52° to 53°N and 2° to 3°E. The sampling grid consisted of 36 stations arranged in six blocks (A to F) of six stations each. From Saturday 29 April 13.28h to Monday 1 May 07.46h, two replicate 2-m beam trawl tows were conducted at 13 stations to estimate density and trophic level of solenette, scaldfish and dab in the southern North Sea. A 30-minute camera tow was carried out over slack water in block A, B and C to provide integrated information on the sedimentary habitat. Due to strong winds with gusts of up to 40 knots, further work was suspended until 14.30h when 2-m beam trawling and camera tows resumed at the remaining stations.
With the sampling grid completed on Thursday 4 May at 10.26h, CEFAS ENDEAVOUR steamed to the Would off Happisburgh (52°49.06N, 01°38.12E to 52°47.62N, 01°40.23E) for a Multibeam survey to comp
|Chief scientist||Michaela Schratzberger (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory)|
|Cruise programme||(0.01 MB)|
|Cruise report||(0.05 MB)|
|Specific||North Sea (ICES IVb) - Silver Pit region|