Report of the Working Group on International Deep Pelagic Ecosystem Surveys - 2 (WGIDEEPS)

The Working Group on International Deep Pelagic Ecosystem Surveys (WGIDEEPS) met in Bremerhaven, Germany, 6-8 August 2018. The meeting, remotely chaired by Kristján Kristinsson, was attended by four participants from Germany and Russia. During the meeting, the group prepared the report on the results from the pelagic redfish (Sebastes mentella) survey conducted in the Irminger Sea and adjacent waters in June/July 2018.
The trawl-acoustic survey on pelagic redfish in the Irminger Sea and adjacent waters was carried out by Russia only. In November 2017, the Marine and Freshwater Research Institute (MFRI) in Iceland informed the group that Iceland would not participate in the survey in June/July 2018. No specific reasons were given for the withdrawal. The participation of Germany was cancelled as well at the beginning of June due to technical problems. Accordingly, the scope of the survey had to be altered and the emphasis was on the detailed coverage of the pelagic redfish above and below 500 m depth in Subarea A.
About 103 000 NM2 were covered, covering the northeastern part of the survey area (Subarea A). As relative survey indices, a biomass of 82 000 t was estimated at depths shallower than DSL by hydroacoustic measurements, about 171 000 t within the DSL, shallower than 500 m by a trawl method, and 130 000 t deeper than 500 m by the trawl method. Since the survey only covered Subarea A, the total biomass is most certainly underestimated. The highest concentrations of redfish above 500 m were found in the southwestern area of Subarea A, whereas the highest concentrations of redfish below 500 m were found in the central part of Subarea A. Since only Subarea A was covered, the comparison of the estimated biomass in previous surveys should be based on this subarea.
WGIDEEPS recommends that the survey should be continued with at least three vessels to cover the distribution area of redfish in the area. The Group recommends that further nations should participate in the next surveys and that chartering of additional vessels and cost share should be considered as alternative to direct participation.