Marine

MRV Scotia: Survey 0216S Programme

January 20, 2016 by Marine Directorate Communications No Comments | Category Compliance, Marine Directorate general, Marine Directorate Science, Research Vessel Surveys

Duration: 23 January – 12 February 2016

Fishing Gear:

• GOV Trawl (BT 137) with ground gear A & B;
• MIK Net (Round Frame with IK depressor); and
• MIKeyM net (attached to the MIK net on selected stations).

Objective:

1. To complete an internationally coordinated demersal trawling survey in the North Sea in ICES area IV.
2. To undertake MIK sampling for pre-metamorphosed herring larvae during the hours of darkness within the trawl survey area. For selected stations additional MIKeyM samples will also be collected from the MIK deployments.
3. To obtain temperature and salinity data from the surface and seabed at each trawling station using a SEABIRD 19+ CTD.
4. Collect additional biological data in connection with the EU Data Collection Framework (DCF).

Trawling:

Hauls of 30 minutes duration will be made using the GOV trawl. Wherever possible, fishing will be carried out during daylight hours as defined below:

For each degree of longitude west, four minutes will be added to the time; for each degree of longitude east, four minutes will be subtracted. The survey area is outlined in the attached chart but the exact fishing position will be decided in collaboration with the fishing master. The Scanmar system will be used throughout the survey to monitor headline height, wing spread, door spread and distance covered during each haul. A bottom contact sensor (BCS) will be attached to the ground-gear and the data collected will be downloaded after each haul. Catches will be processed according to standing sampling protocols with additional biological data collected for species as required.

MIK Sampling:

Pre-metamorphosed herring larvae will be sampled during the hours of darkness with the MIK mid-water trawl (Round frame). Two double oblique tows will be made in every square within the assigned survey area. The vertical profile of the tow will be monitored using the Scanmar system. During this survey the small 20 mm round frame net (MIKeyM net) will also be deployed on selected MIK stations for the purpose of collecting pelagic fish eggs from the survey area. See Figure 2 for locations where the MIKeyM net will be deployed and for proposed locations for Scotia. Hydrography: Surface and bottom temperatures, salinities, nitrates, silicates and phosphates will be taken at all trawl stations. The ships thermosalinograph will be run continuously throughout the survey.

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Further Information:

Scotia Survey 0216S – Figures 1 and 2

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