Marine Scotland

Testing the water with an International Bottom Trawl Survey

November 13, 2017 by No Comments

1617S Trawl positions for each core station (solid circle) and alternative/additional positions (empty circles) will be added as time allows.

Duration: 13 November – 3 December 2017

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

Objectives:

  1. To participate in the ICES co-ordinated western division demersal trawling survey.
  2. To obtain temperature and salinity data profiles at each trawling position.
  3. To collect additional biological data in connection with the EU data collection framework (DCF).

Procedures:

All fishing gear and scientific equipment will be loaded aboard during the landing day of 1517S. Scotia will sail on 13 November and (after all safety drills and shakedown trawl shoot) commence fishing operations the following morning on the 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 SIC after daily consultation with Fishing Master and Captain.  A half landing with be made around 23 or 24 November into Greenock or possibly Belfast to exchange staff, but the date and port are to be confirmed once the vessel has commenced the survey.

Trawling:

This is a random-stratified survey design with trawl stations being distributed within twelve predefined strata covering the sampling area. One trawl haul of thirty minutes duration will be made within a radius of five nautical miles of each core positions shown on the attached chart.  If trawling is not possible at the core location then the nearest appropriate secondary/alternative station will be used.  Final trawl locations will be decided after SIC consultations with Fishing Master.  For each haul, the Scanmar monitoring system and NOAA bottom contact sensor will be used to observe and record the performance and geometry of the trawl and trawl doors.

Fish Sampling:

All fish will be treated according to current standard research vessel procedures and additional biological data will be collected as determined by EU data regulation 1639/2001 and 1581/2004.

Hydrography Sampling:

CTD casts will be taken at each trawl station. Please note the thermosalinograph will not be run during this survey.

Further Information:


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