Marine Scotland

Demeral Trawling Survey on the West Coast

November 6, 2019 by No Comments | Category Marine Scotland general, Marine Scotland Science, Research Vessel Surveys, Uncategorized

MRV Scotia

Survey: 1719S

Duration: 4 – 25 November 2019

Fishing Gear: GOV Trawl (BT137) and ground gear D (hoppers).

Objectives:

  1. Participate in the International Council for the Exploration of the Sea (ICES) coordinated western division demersal trawling survey.
  2. Obtain temperature and salinity data profiles at each trawling position.
  3. Collect additional biological data in connection with the EU Data Collection Framework (DCF).
  4. Retrieval and redeployment of Collaborative Oceanography and Monitoring for Protected Areas and Species (COMPASS) mooring at Stanton Bank deployed during previous survey.

Procedures:

MRV Scotia will sail on 4 November and (after all safety drills and shakedown trawling) commence fishing operations the following morning on stations to the west of the Orkneys. Weather conditions at the time will determine the exact start area. Survey schedule and operations will be decided by Scientist-in-Charge (SIC) after daily consultation with Fishing Master and Captain.

Figure 1. 1719S trawl locations. Note – tow positions for each core station (solid circle) and alternative/additional positions (empty circles) will be added as time allows.

Trawling:

This is a random-stratified survey design with trawl stations being distributed within 12 predefined strata covering the sampling area (Figure 1). A more detailed map showing the Clyde trawl stations in relation to the underwater cable installed in 2017 is provided in Figure 2. A total of 60 primary and 38 secondary stations have been generated. The intention is for 60 trawls to be undertaken on suitable ground as near to the specified primary sampling positions (Table 1) as is practicable, and where possible within a radius of five nautical miles of the sampling position. In the event that trawling is not possible within 5 nm of any primary station then the nearest appropriate secondary station will be used. Hauls will be of 30 minutes duration unless circumstances dictate otherwise. Where possible, fishing operations will be restricted to daylight hours. Exact start and finish times will vary slightly according to geographical location.

Figure 2. Map showing Clyde stations in relation to cable installed in 2017. Note – The blue line shows the location of the deep-water cable installed in 2017 and the red dotted line shows the ± 1.5 nmi safety area around the cable.

The Scanmar system will be used to monitor the headline height, wing spread and door spread for each haul. Bottom contact data from each trawl will also be collected using the NOAA bottom contact sensor, which will be mounted on a bar in the middle of the ground-gear. In addition to the routine sampling, biological data will be collected for target species in line with the EU data regulation.

Fish Sampling:

All fish will be processed in accordance with the protocols as described in the Manual of the IBTS North Eastern Atlantic Surveys. Series of ICES Survey Protocols SISP 15. 92 pp.

Hydrography Sampling:

Conductivity Temperature Depth (CTD) casts will be taken at each trawl station, weather permitting.

COMPASS Moorings:

During the survey one day will be allocated to the retrieval and redeployment of two acoustic moorings deployed during a previous survey. The intention is to undertake this objective during Part 1 of the survey with an acoustic release system being deployed from the vessels side deck to trigger the moorings.

Table 1: 1719S – Position of primary sampling stations

Station lat lon deglat deglon stratum
1 58.96247 -4.607729 5857.75N 0436.46W green1
2 59.3044 -4.30137 5918.26N 0418.08W green1
3 59.25443 -4.732363 5915.27N 0443.94W green1
4 59.28047 -5.119988 5916.83N 0507.20W green1
5 59.63196 -4.834488 5937.92N 0450.07W windsock
6 60.03191 -4.545194 6001.91N 0432.71W red1
7 59.48743 -5.328187 5929.25N 0519.69W windsock
8 59.50362 -5.699959 5930.22N 0542.00W windsock
9 59.64184 -6.193042 5938.51N 0611.58W red1
10 59.48501 -6.576728 5929.10N 0634.60W red1
11 59.21047 -6.160272 5912.63N 0609.62W windsock
12 58.74089 -6.429035 5844.45N 0625.74W green1
13 58.92074 -6.565814 5855.24N 0633.95W green1
14 58.96038 -6.969687 5857.62N 0658.18W green1
15 58.9769 -7.473466 5858.61N 0728.41W red1
16 58.2913 -7.32209 5817.48N 0719.33W green1
17 58.58162 -7.988137 5834.90N 0759.29W red1
18 58.39124 -8.466181 5823.47N 0827.97W red1
19 58.5036 -8.70768 5830.22N 0842.46W red1
20 58.20023 -8.886268 5812.01N 0853.18W red1
21 57.66401 -8.378741 5739.84N 0822.72W green2
22 57.62313 -9.37477 5737.39N 0922.49W red1
23 57.16478 -9.20848 5709.89N 0912.51W red2
24 57.07604 -8.903222 5704.56N 0854.19W red2
25 56.77223 -8.283156 5646.33N 0816.99W green2
26 56.59257 -8.842584 5635.55N 0850.56W red2
27 56.33942 -8.96371 5620.37N 0857.82W red2
28 55.88948 -9.045951 5553.37N 0902.76W red2
29 55.69321 -8.855828 5541.59N 0851.35W red2
30 55.16835 -9.2548 5510.10N 0915.29W red2
31 55.20564 -9.972894 5512.34N 0958.37W red2
32 55.05976 -9.784037 5503.59N 0947.04W red2
33 54.96405 -9.499039 5457.84N 0929.94W green4
34 54.7919 -9.428163 5447.51N 0925.69W green4
35 54.47329 -10.444974 5428.40N 1026.70W gray
36 54.29499 -10.352855 5417.70N 1021.17W gray
37 54.413 -9.131841 5424.78N 0907.91W gray
38 54.4843 -8.792802 5429.06N 0847.57W gray
39 54.86623 -8.753432 5451.97N 0845.21W red2
40 55.47931 -8.700307 5528.76N 0842.02W red2
41 55.7661 -8.204705 5545.97N 0812.28W green3
42 55.66018 -7.7588 5539.61N 0745.53W green3
43 55.48171 -7.402395 5528.90N 0724.14W red2
44 55.73953 -7.248396 5544.37N 0714.90W green3
45 55.20804 -5.705191 5512.48N 0542.31W blue2
46 55.19889 -4.993599 5511.93N 0459.62W clyde
47 55.36414 -5.306141 5521.85N 0518.37W clyde
48 55.5974 -4.982199 5535.84N 0458.93W clyde
49 56.1898 -6.032125 5611.39N 0601.93W blue2
50 56.10104 -7.45851 5606.06N 0727.51W green3
51 56.21185 -7.819209 5612.71N 0749.15W green3
52 56.37653 -7.55737 5622.59N 0733.44W lightblue
53 56.57917 -7.905759 5634.75N 0754.35W lightblue
54 56.66497 -7.208751 5639.90N 0712.53W lightblue
55 56.60989 -6.868622 5636.59N 0652.12W lightblue
56 57.43943 -6.883278 5726.37N 0653.00W lightblue
57 57.64108 -6.700875 5738.46N 0642.05W blue1
58 57.95637 -6.064734 5757.38N 0603.88W blue1
59 58.03786 -5.631351 5802.27N 0537.88W blue1
60 58.72933 -4.18985 5843.76N 0411.39W green1

Additional Information:


Tags: , , , , , , , , , , , , , , , , , , , , , ,

Comments

Leave a comment

By submitting a comment, you understand it may be published on this public website. Please read our privacy policy to see how the Scottish Government handles your information.

Your email address will not be published. Required fields are marked *