| Summary: | This data set has trawl catch weight and biological measurements from the latter half of the Icelandic part of the International Ecosystem Summer Survey in Nordic Seas (IESSNS) conducted in July 2021. The survey area was from the coast and over the shelf edge south and west of Iceland, defined as IESSNS strata 5 and 6, see embedded map. The survey period was July 17 – 26, 2021, and samples were collected at 38 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 38 stations. Trawl depth ranged from surface (trawl headline in surface) at 22 stations and 8 stations was trawling deeper in the water column targeting specific acoustic backscatter with trawl depth of 100 – 400 m. 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), herring (Clupea harengus), and mackerel (Scomber scombrus) more biological measurements are provided such as sex, maturity, age, and stomach weight. For age determination, the otolith or scale was extracted whole from specimen 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. For taxa Scyphozoa and Natantia decapods only total catch weight per station is recorded. For detailed information about the survey see the survey report (Ólafsdóttir et al. 2022) in Icelandic and abstract, figure and table headings also provided in English. Various information about the trawling operation and weather is included in file. The data is provided by the Marine and Freshwater Research Institute (MFRI) in Iceland.
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