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FRV Alba Na Mara 0915A
Cruise summary report
|Ship name (ship code)||FRV Alba Na Mara (74NM)|
|Cruise period||2015-06-10 — 2015-06-30|
|Port of departure||Fraserburgh, United Kingdom|
|Port of return||Fraserburgh, United Kingdom|
1. To undertake an acoustic survey of sandeels and clupeid fish in the water column using 38 and 120 kHz.
2. To conduct RoxAnn survey of the substrate along all acoustic survey tracks.
3. To conduct seabirds-at-sea survey and a survey of marine mammals along the acoustic survey track.
4. To assess abundance, length-frequency-distribution, and age- weight-at-length of demersal fish predators at eight fixed stations in the Firth of Forth area by demersal trawl survey.
5. To assess abundance, length-frequency-distribution, and age- weight-at-length of demersal fish, and abundance and total biomass of benthic invertebrates, in the Neart na Gaoithe development site and three further control areas.
6. To assess abundance, length-frequency-distribution, and age- weight-at-length of sandeels in the Neart na Gaoithe development site and three further control areas.
7. To conduct a UW TV survey of stations in the Neart na Gaoithe development site and three further control areas.
8. To conduct a survey of demersal fish using fish traps in the Neart na Gaoithe development site and three further control areas.
Scientists joined the vessel at 17:00 hours on the evening of 9 June, making way for the study site at 04:00 hours the next day. The acoustic survey began on the morning of 11 June. Five transects were surveyed acoustically at 38 and 120 kHz to examine the abundance of sandeels and clupeid fish in the water column. Concentrations of fish were sampled in three trawls using the PT154 pelagic trawl. Species composition and length frequency distributions of fish caught were determined, sub-samples were weighed and their otoliths removed to establish length-weight relationships and age composition. RoxAnn data was collected throughout the acoustic transects to support the development of seabed sediment maps. Seabirds at sea data was also collected simultaneously using standard transect census methods to determine the numbers of seabirds using the study area on a daily basis, and their distribution over the area. The acoustic survey was completed on the afternoon of 13 June. At this time, the Alba na Mara made way for Montrose to load on nets for the demersal survey.
Alba na Mara left Montrose to begin the demersal survey at 14:00 hours on 13 June. Eight demersal trawl stations were fished using the BT158 over the next two days. All eight demersal stations have been fished in previous PICMATOP cruises, supporting a database extending back to 1997. Each catch was worked up to determine numbers at length of all species caught. Trawl performance metrics were recorded using Scanmar equipment to enable swept area to be determined. In addition, size stratified samples of cod, haddock and whiting were weighed to determine their length-weight relationships. The abundance and biomass of selected invertebrate species was also recorded from each catch.
On 15 June, Alba na Mara made way for Montrose. Due to a failure in the steering mechanism, the vessel remained at her berth in Montrose for the following four days awaiting repair. Due to the concomitant loss of survey days, the planned switch over to the TV survey was cancelled. Changes in scientific crew roster were also made to accommodate this change. Once repairs were effected, the vessel returned to the survey site at 12:00 hours on 19 June to begin the beam trawl survey. A further crew change was undertaken on the morning of 20 June. The beam survey resumed at 13:00 hours on the same day and continued until a reoccurrence of the steering problem on 23 June forced the vessel to return to port. The vessel berthed in Leith at 13:30 hours awaiting engineering support. The vessel resumed the survey activitiesat 16:00 hours on 25 June. However, all survey activity ceased on the evening of 26 June due to a further recurrence of the steering problem. Due to safety concerns, it was decided to end the survey at this point.
|Chief scientist||Philip Boulcott (Marine Scotland Aberdeen Marine Laboratory)|
|Cruise programme||(0.99 MB)|
|Cruise report||(0.52 MB)|
|Specific||Firth of Forth|