Audacious 0723H
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | Audacious (74UP) |
| Cruise identifier | 0723H |
| Cruise period | 2023-05-10 — 2023-05-23 |
| Status | Completed |
| Port of departure | Ullapool, United Kingdom |
| Port of return | Peterhead, United Kingdom |
| Purpose | Research |
| Objectives | Objectives
1. To undertake the Scottish Irish Anglerfish Megrim Industry Science Survey (SIAMISS). An annual nationally coordinated demersal trawling survey of Anglerfish (Lophius piscatorius and Lophius budegassa), Megrim (Lepidorhombus whiffiagonis) and Four-Spot Megrim (Lepidorhombus boscii) in the North Sea (ICES area IVa). 2. To collect species distribution, length frequency and biological data of Anglerfish (Lophius piscatorius and Lophius budegassa), Megrim (Lepidorhombus whiffiagonis), Four-Spot Megrim (Lepidorhombus boscii) Cod (Gadus morhua), Blue Skate (Dipturus batis) and Flapper Skate (Dipturus intermedius). 3. To collect additional species distribution, length frequency and biological data in connection with the EU Data Collection Framework (DCF). Narrative The SIAMISS survey utilises a semi-random-stratified survey design with random station positions generated based on area and anglerfish catch variability within five predefined strata within ICES areas VIa (NW shelf and slope) and five at VIb (Rockall) to a maximum depth of 1000m in both cases. Positions for a total of 13 primary and 37 alternative stations were generated for the NW shelf and slope along with those for 23 primary and 44 secondary stations at Rockall. Primary stations were the main focus with alternative stations being utilised to increase effort or to replace primary stations where survey was not practical. A 5 nm buffer was applied to the positions and trawling was undertaken within this buffer with the intention of transecting the center of the position during the tow where possible. Trawl locations within the buffer zone were agreed on an individual basis by daily consultation between skipper and SIC, taking in factors such the requirement to avoid protected or sensitive marine habitats, the presence of static fishing gear, commercial trawlers operations or simply unsuitable ground. A combination of established trawl locations along with those previously unfished by Audacious were used to complete the survey. Cruise 0723H represents the 3rd cruise out of 3 in terms of Scotland’s commitments to SIAMISS. The trawl gear (BT195) was used throughout the survey and was deployed 49 times giving a final total of 44 valid stations, well up on the 36 programmed for the cruise. Primary stations were used on 23 occasions with another 21 being alternatives. Commercial fishing conflict, positions generated in protected areas, poor or unknown ground at the primary station along with the undertaking of additional stations were the main factors influencing the relatively high proportion of alternatives in the total. An MD-built bespoke bottom contact sensor was attached to the trawl's groundgear during each tow to monitor ground contact as well as to validate record of touch-down and lift-off of the groundgear. Scanmar sensors collected data on the spread of trawl wings and doors, and headline height. Valid trawl duration was typically the standard of 60 minutes, with only 1 haul being shorter (by 3 minutes) as it was hauled immediately on coming fast after 57 minutes. There were five occasions of foul hauls, one of which four were repeated. All target species were identified, weighed, and measured to generate a length frequency and individual biological data were collected according to pre-set survey sampling targets. Due to logistical limitations on chartered commercial vessels and the low levels of scientific staffing only the target species were recorded during 0723H. Data was collected on: Anglerfish (both species), Megrim, Cod, Four-spot megrim, Blue Skate, Flapper Skate, Black Skate (Dipturus nidarosiensis), Blue Ray (Neoraja caerulea), Fyllas Ray (Rajella fyllae), Long nosed Skate (Dipturus oxyrinchus), Sandy Ray (Leucoraja circularis) an |
| Chief scientist | James Drewery (Marine Scotland Aberdeen Marine Laboratory) |
| Cruise programme |  (0.79 MB) |
| Cruise report | (0.36 MB) |
| Ocean/sea areas | |
| General | North East Atlantic Ocean (limit 40W) |
| Specific | Rockall Bank, Wyville Thompson Ridge, Scottish Continental Slope |
| Measurements | |
| Biology and fisheries | |
| Demersal fish | Quantity: number of hauls = 44 Description: Demersal trawl deployments and associated catch data. |
