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    This data set has trawl catch weight and biological measurements from the 2nd leg of the Icelandic part of the International Ecosystem Summer Survey in Nordic Seas (IESSNS) conducted in July 2020. The survey area was from the coast, over the shelf edge and into the deep-water basins south of Iceland and in the southern part of the Irminger Sea, defined as IESSNS strata 6, 11 and 12, see embedded map. The survey period was July 11 – 30, 2020, and samples were collected at 27 trawl stations. A specifically designed scientific trawl, called Multpelt832 (ICES, 2013a-b, Valdemarsen et al 2014) with cod-end mesh size of 50 mm, was used at all 27 stations. Trawl depth ranged from surface (trawl headline in surface) to 550 m depth. All trawl catch was identified to lowest possible taxonomic level, total weight of each species recorded, and length and weight of 50 specimen per species measured, or all if less was caught. For blue whiting (Micromesistius poutassou) more biological measurements are provided such as sex, maturity, age, and stomach weight. For age determination, the otolith was extracted whole from the blue whiting at sea and read whole under a dissecting microscope on land by an experienced age reader part of the ICES framework. Gonad maturity stage was visually estimated at sea during sampling by an experienced technician. The maturity stages are 1-7, where 1 is immature, 2 is beginning to mature or beginning to recovering from previous spawning event, 3 is maturing, 4 is maturing, 5 is getting fully mature, 6 is spawning, and 7 has finished spawning. For the taxa Scyphozoa and Natantia decapods only total catch weight per station is recorded. In total, length measurements are provided for 1383 specimens and weight for 1231 specimen. Each specimen is one row in the dataset file. Information for three pelagic fish species is excluded from the data set and these species are mackerel (Scomber scombrus), herring (Clupea harengus) and lump fish (Cyclopterus lumpus). For detailed information about the survey see the survey report (in English): https://www.hafogvatn.is/is/midlun/utgafa/haf-og-vatnarannsoknir/results-of-the-icelandic-part-of-the-international-ecosystem-summer-survey-in-nordic-seas-iessns-in-2020-on-rv-arni-fridriksson Various information is provided about the trawling operation and weather. The data is provided by the Marine and Freshwater Research Institute (MFRI) in Iceland.