FRV Alba Na Mara 0111A
|Ship name (ship code)||FRV Alba Na Mara (74NM)|
|Cruise period||2011-01-10 — 2011-01-24|
|Port of departure||Fraserburgh, United Kingdom|
|Port of return||Fraserburgh, United Kingdom|
1. To obtain estimates of the Nephrops habitat distribution in West Coast Sea Lochs, using sediment grabs and underwater cameras.
2. To obtain estimates of the distribution and abundance of Nephrops within these lochs using underwater video cameras.
3. To use the video footage to record occurrence of other benthic fauna and evidence of commercial trawling activity.
4. To collect trawl caught samples of Nephrops for comparison of reproductive condition and morphometrics.
This survey continues on from the work begun in February 2010 (cruise 0110A).
For each area within the survey, a position outwith the suspected Nephrops habitat boundary will be nominated as the start point for a search path across the length or breadth of the area, which will typically be a loch or bay. Along this search path the drop frame will be deployed to provide a visual record of the seabed type, followed by a Day grab at a suitable point along the track (if appropriate). Sediment samples will be frozen. The distance between these deployments will vary between each specific area surveyed.
The search path will continue in one direction until it appears that the presence or absence of muddy sediment becomes apparent. All significant observations will be recorded on DVD as well as manually, including the muddy sediment boundary, the point where Nephrops burrows begin to appear and any signs of fishing activity.
Once an area has been surveyed to establish the extent of the muddy habitat, depending on time and weather a selection of stations will be surveyed for Nephrops abundance, whereby the drop frame will be deployed over known Nephrops grounds for 10 minutes and the number of Nephrops burrow complexes will be recorded. The number of TV stations to be completed will be determined by the extent of the muddy grounds and available time. Although using the TV sledge is the preferred method of video capture for abundance purposes, due to the high probability of creels present in the proposed survey areas the drop frame is more appropriate.
The latitude and longitude of the proposed start points for each survey area will be made available to the ship's complement prior to the cruise.
Weather permitting, the highest priority areas to be covered in this survey are:
Loch Ewe, Gair Loch, Outer and Upper Loch Torridon, Shieldaig Bay, Loch Kishorn, Loch Carron, Loch Alsh and Loch Duich.
Some further work maybe required at Gruinard Bay and Eddrachillis Bay but this is dependant on weather and available time.
It is hoped that at least two trawls can be carried out to the North of Rona, each one hour long; one within the Trawl Only area and one outside this area. A range of biological data will be collected on Nephrops and other shellfish. The trawl gear to be used is under construction at present but will be similar to previous prawn trawl gear used on Alba na Mara, although six and eight-inch disks will be incorporated on the ground rope. All enquiries relating to the gear should be directed to R Kynoch at Marine Scotland Science.
TV work will take place during daylight hours. There will be a requirement for some trawling to take place in the evening. On days where trawling will take place, work patterns will be arranged so as not to exceed WTD recommendations.
|Chief scientist||Adrian Weetman (Marine Scotland Aberdeen Marine Laboratory)|
|General||Inner Seas off the West Coast of Scotland|
|Specific||West Coast Sea Lochs|