Results of the Icelandic part of the International Ecosystem Summer Survey in Nordic Seas (IESSNS) in July 2022 on R/V Árni Friðriksson

Abstract

The Marine and Freshwater Research Institute (MFRI) has participated in the International Ecosystem Summer Survey in Nordic Seas (IESSNS) every summer since 2010. The aim of IESSNS is to monitor the pelagic ecosystem from 0‐500 m depth, including measurements of nutrients, primary production, temperature, salinity, zooplankton, and determine abundance and geographical distribution of mackerel (Scomber scombrus), blue whiting (Micromesistius poutassou), herring (Clupea harengus) and lumpfish (Cyclopterus lumpus). In summer 2022, the Icelandic part of IESSNS was conducted July 4‐21, on R/V Árni Friðriksson, and covered Icelandic waters, except the east area which was covered by vessels from Faroe Islands and Norway, and a few stations in Greenlandic and international waters. Survey transects were 3759 nautical miles and 243 stations were sampled, predetermined survey sampling and additional sampling for research projects. Mackerel was caught at 63% of surface trawl stations located west, south and north of Iceland. Mackerel occupied waters south and west of Iceland for the first time since 2019 but the density was lower than measured from 2013 to 2019. Surface temperature, 10 m depth, ranged from 1.9 °C to 11.6 °, and was highest south of Iceland and coldest in the Denmark Strait. Mesozooplankton dry weight ranged from 1.3‐21.1 g*m‐2 and the biomass was greater north of Iceland compared to waters in the west and south. Despite favorable temperature and prey conditions west and south of Iceland, mackerel density was low compared to the period 2013 – 2019. The survey abundance index for Norwegian spring‐spawning herring and its distribution and density had increased north and northwest of Iceland compared to 2021. Blue whiting was present along the shelf edge south of Iceland and part of the shelf west of Iceland. It was mostly age‐1 blue whiting. In total, 188 kg of lumpfish was caught which is only 28% of the catch in 2021. 67 lump fish were tagged.