Results of the Icelandic part of the International Ecosystem Summer Survey in Nordic Seas (IESSNS) in 2020 on R/V Árni Friðriksson

Abstract

The Marine and Freshwater Research Institute has participated in the International Ecosystem Summer Survey in Nordic Seas (IESSNS) every summer since 2010. The aim is to monitor the pelagic ecosystem including measurements of nutrients, temperature, salinity, mesozooplankton, abundance and geographical distribution of mackerel (Scomberscombrus), blue whiting (Micromesistius poutassou), herring (Clupea harengus) and lumpfish (Cyclopterus lumpus). In 2020, the Icelandic part of IESSNS was conducted from July 1st to 30th on R/V Árni Friðriksson in Icelandic and Greenlandic exclusive economic zones, and in international waters. Survey track was 5596 nautical miles and a total of 181 stations were sampled for the survey and 112 stations for various other research projects. Mackerel was caught at 24 % of predetermined surface trawl stations and the highest density was in inshore waters southeast of Iceland. No mackerel was caught north and northeast of Iceland. Temperature of the surface mixed layer, ranged from 2.1 °C to 12.1 °C. Areas with temperatures suitable for mackerel (> 9 °C) were found south of Iceland, both inshore and offshore, and in the southern Irminger Sea, however mackerel was only present in a small part of the area. Mesozooplankton dry weight ranged from 1.3 gm‐2 to 19.4 gm‐2. Direct effects of temperature and mesozooplankton availability cannot explain low abundance of mackerel. Herring was present in shelf areas south of Iceland, and both in shelf areas and offshore in areas north and northeast of Iceland. This is similar distribution pattern compared to previous years. Blue whiting was only present in a small area east of Iceland which is a decline in distribution compared to previous years when blue whiting has been distributed along the shelf edge south of Iceland.

Publication
Haf- og vatnarannsóknir
James Kennedy
James Kennedy
Fish biologist