Report of the International Bottom Trawl Survey Working Group (IBTSWG). 19 - 23 March 2018 Oranmore, Ireland

Type Scientific report
Date 2018
Language English
Ref. ICESCM 2018/EOSG:01
Author(s) ICES
Contributor(s) Sell Anne, Auber ArnaudORCID, Bland Barbara, Lynam Christopher, Stokes David, Foucher EricORCID, Olsen Erik, Burns Finlay, Baldo Francisco, Velasco Francisco, Travers-Trolet MorganeORCID, Jourdain Natoya, Schuchert Pia, Van Hal Ralf, Kynoch Robert, Soni Vaishav

The report summarizes the national contributions in 2017–2018 and planning for 2018–2019 for the surveys coordinated by the International Bottom Trawl Survey Working Group (IBTSWG). In the North Sea, the surveys are performed in quarters 1 and 3 while in the Northeast Atlantic the surveys are conducted in quarters 1, 3, and 4 with a suite of 14 national surveys covering shelf areas from north off Scotland to the Gulf of Cádiz. Results achieved during the 3 year cycle are briefly summarized or reference to previ-ous reports is given.

North Sea Q1, 2018: Seven countries using six different vessels participated and per-formed 364 valid GOV hauls and 567 valid MIK hauls in the period between 17th Jan-uary and 28th February. All rectangles were covered by at least 1 GOV haul. There were, however, a number of rectangles, which could not be sampled with the MIK due to technical problems with the Scottish and the German vessel. Consequently, 8 rectan-gles in the northwest of the survey area weren’t sampled at all. This was managed despite poor weather conditions, and required some shifts in stations between coun-tries. In particular, Norway and Denmark did some additional GOV and MIK in rec-tangles, which had originally been allocated to Germany. Denmark and Sweden used both “DANA” and France used “Tridens” for a few days because “Thalassa” was not available in the beginning of the survey. As usual, all countries used their own survey gear. Overall, most of the countries reported small to very small catches with the GOV.

North Sea Q3, 2017: Six countries using five different vessels participated and per-formed 337 valid GOV hauls in period 17 July to 2 September. Denmark and Sweden used both “DANA” but with their own survey gear. The total number of hauls was lower than in the two previous years since all counties resembled using 30 min stand-ard tows only after the use of 15 min tows were abandoned. While some rectangles did not achieve coverage of two hauls, the number of rectangles with only one haul was less than in any year since 2010 due to some reallocation of rectangles to the different countries.

Northeast Atlantic 2017: Seven vessels from five countries performed 13 surveys in the North-eastern Atlantic IBTS area. A total of 950 valid hauls, out of the 1062 hauls planned, were accomplished within 277 days distributed between the first, third and fourth quarters. Besides, 110 hauls and 21 days were done by the RV Celtic Explorer during the mentioned IE-IAMS-Q1. The most remarkable event has been the breakage of the RV Thalassa during the FR-EVHOE survey, which was reduced to 25 valid hauls in northern part of the French shelf on the Biscay Bay. The Marine Institute of Ireland prolonged their groundfish survey on the subarea 7 to perform some extra 22 hauls on the Celtic Sea area to cover the gap left by the breakage.

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