Resources

FRV Alba Na Mara 1319A

Cruise plan

Cruise Info. 
Ship name (ship code)FRV Alba Na Mara (74NM)
Cruise identifier1319A
Cruise period2019-08-08 — 2019-08-24
StatusCompleted
Port of departureFraserburgh, United Kingdom
Port of returnFraserburgh, United Kingdom
PurposeResearch
ObjectivesObjectives

- To obtain estimates of the distribution and abundance of Nephrops burrows in the Firth of Forth and the Moray Firth using underwater cameras.
- To use the TV footage to record the occurrence of other benthic fauna and evidence of commercial trawling activity.
- To collect trawl caught samples of Nephrops for comparison of reproductive condition and morphometrics in each of the different survey areas.
- If time permits, deployments of the sledge followed by the drop frame will be carried out on the same ground to compare Nephrops burrow density estimates obtained by using the two different methods.

Procedure

Where possible, a random stratified approach will be adopted to investigate Nephrops burrow density in different regions of the study areas. A list of proposed stations for the survey will be made available to the ship prior to sailing.

1. TV Observations: At each station a video camera mounted on the TV sledge will be towed across the seabed, into the tide and for approximately ten minutes at approximately one knot. Nephrops burrow abundance, other benthic fauna and signs of anthropogenic activity will be recorded on to DVD. Distance traveled by the sledge, the depth at which the sledge is at and camera height from the seabed will be monitored and recorded automatically.
2. Trawling: Fishing trawls of approximately 60 minutes duration will be made within each sediment type and within each survey area. A range of biological and morphometric data will be collected on Nephrops caught.
3. Drop Frame: The drop frame will be used where conditions are not suitable for using the TV sledge, recording similar data as to that of the TV sledge.
4. Comparative work: Following on from work carried on previous surveys, on known Nephrops grounds the sledge will be towed along parallel tracks approximately 200 m in length (ten minutes towing time) and 100 m apart. Video footage and all observed data will be recorded as usual. Following this, the drop frame will then be drifted across the same area at 90 degrees to the sledge tracks. The frequency of this operation will depend on the weather and available time.
Chief scientistGerald McAllister (Marine Scotland Aberdeen Marine Laboratory)
Cruise programmeFRV Alba Na Mara 1319A cruise programme 1319a.pdf  (0.03 MB) 
Ocean/sea areas 
GeneralNorth Sea
Unknown
SpecificFirth of Forth, Moray Firth