Estimated consumption of polar cod by Atlantic cod in the Barents Sea (yellow line) and biomass of the Atlantic cod stock in the Barents Sea (red line) (ICES 2016). The blue line is the biomass of the Barents Sea polar cod (Prozorkevich 2016). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/marine-fishes" target="_blank">Chapter 3</a> - Page 116 - Box figure 3.4.1

Figure 3.2.1a: Map of high throughput sequencing records from the Arctic Marine Areas. Figure 3.2.1b: Map of records of phytoplankton taxa using microscopy from the Arctic Marine Areas. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/plankton" target="_blank">Chapter 3</a> - Page 35 - Figure 3.2.1a and Figure 3.2.1b In terms of stations sampled, the greatest sampling effort of high-throughput sequencing in Arctic marine water columns, by far, has been in the Beaufort Sea/Amundsen Gulf region and around Svalbard. High through-put sequencing has also been used on samples from the Chukchi Sea, Canadian Arctic Archipelago, Baffin Bay, Hudson Bay, the Greenland Sea and Laptev Sea.

Multi-decadal time series of A) abundance (individuals m-2) and B) biomass (g wet weight m-2) of ice amphipods from 1977 to 2012 across the Arctic. Bars and error bars indicate median and median absolute deviation (MAD) values for each year, respectively. Numbers above bars represent number of sampling efforts (n). Modified from Hop et al. (2013). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/sea-ice-biota" target="_blank">Chapter 3</a> - Page 45 - Figure 3.1.7 From the report draft: "The only available time-series of sympagic biota is based on composite data of ice-amphipod abundance and biomass estimates from the 1980s to present across the Arctic, with most observations from the Svalbard and Fram Strait region (Hop et al. 2013). Samples were obtained by SCUBA divers who collected amphipods quantitatively with electrical suction pumps under the sea ice (Lønne & Gulliksen 1991a, b, Hop & Pavlova 2008)."

Megafauna distribution of biomass (g/15 min trawling) in the Barents Sea in 2007, 2011 and 2015. The green circles show the distribution of the snow crab as it spreads from east to west, and the blue triangles show the invasion of king crab along the coast of the southern Barents Sea. Data from Institute of Marine Research, Norway and the Polar Research Institute of Marine Fisheries and Oceanography, Murmansk, Russia. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/benthos" target="_blank">Chapter 3</a> - Page 95 - Figure 3.3.2 The annual joint Norwegian–Russian Ecosystem Survey provides from more than 400 stations and during extensive cruise tracks covering more or less the whole Barents Sea in August– September. The sampling is based on a regular grid spanning about 1.5 millionkm2 with fixed positions of stations which make it possible to measure changes in spatial distribution over time. The trawl is a Campelen 1800 bottom trawl rigged with rock-hopper groundgear and towed on double Warps. The mesh size is 80 mm (stretched) in the front and 16–22 mmin the cod end, allowing the capture and retention of smaller fish and the largest benthos from the seabed (benthic megafauna). The horizontal opening was 11.7 m, and the vertical opening 4–5 m (Teigsmark and Øynes, 1982). The trawl configuration and bottom contact was monitored remotely by SCANMAR trawl sensors. The standard distance between trawl stations was 35 nautical miles (65 km), except north and west of Svalbard where a stratified sampling was adapted to the steep continental shelve. The standard procedure was to tow 15 min after the trawl had made contact with the bottom, but the actual tow duration ranged between 5 min and 1 h and data were subsequently standardized to 15 min trawl time. Towing speed was 3 knots, equivalent to a towing distance of 0.75 nautical miles (1.4 km) during a 15 min tow. The trawl catches were recorded using the same procedures on the Russian and the Norwegian Research vessels to ensure comparability across Barents Sea regions. The benthic megafauna was separated from the fish and shrimp catch, washed, and sorted to lowest possible taxonomic level, in most cases to species, on-Board the vessel. Species identification was standardized between the researcher teams by annually exchanging the benthic expert’s among the vessels and taxon names were fixed each year according toWORMSwhen possible.This resulted in an Electronic identification manual and photo-compendium as a tool to standardize taxon identifications, in addition to various sources of identification literature. Difficult taxa were photographed and, in some cases, brought back as preserved voucher specimens for further identification. Wet-weight biomass was recorded with electronic scales in the ship laboratories for each taxon.The biomass determination included all fragments.

Arthropods (e.g., shrimps, crabs, sea spiders, amphipods, isopods) dominate taxon numbers in all Arctic regions, followed by polychaetes (e.g., bristle worms) and mollusks (e.g., gastropods, bivalves). Other taxon groups are diverse in some regions, such as bryozoans in the Kara Sea, cnidarians in the Atlantic Arctic, and foraminiferans in the Arctic deep-sea basins. This pattern is biased, however, by the meiofauna inclusion for the Arctic Basin (macro- and meiofauna size ranges overlap substantially in deep-sea fauna, so nematodes and foraminiferans are included) and the influence of a lack of specialists for some difficult taxonomic groups. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/benthos" target="_blank">Chapter 3</a> - Page 89 - Box figure 3.3.1 Each region of the Pan Arctic has been sampled with a set of different sampling gears, including grab, sledge and trawl, while other areas has only been sampled with grab. Here is the complete species/taxa number and the % distribution of species/taxa in main phyla, per region of the Pan Arctic.

Boundaries of the 22 ecoregions (grey lines) as defined in the CSMP (Irons et al. 2015) and the Arctic Marine Areas (colored polygons with names in legend). Filled circles show locations of seabird colony sites recommended for monitoring (‘key sites’). The current level of monitoring plan implementation are green = fully implemented, amber = partially implemented, red = not implemented. The CSMP provides implementation maps for each forage guild. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/seabirds" target="_blank">Chapter 3</a> - Page 132 - Figure 3.5.1 This graphic displays the status of seabird monitoring at key sites in CBMP areas across the Arctic.

Seasonal abundance (1000 individuals m- 2) of sea ice meiofauna at landfast sea ice (Barrow, 2005-2006, A and C) and pack ice (North of Svalbard, 2015, B and D). A and B show larval stages (polychaete juveniles and nauplii, respectively), while C and D show nematodes and harpacticoid copepods, respectively. Circles represent individual cores (n = 107 for A and C, and 39 for B and D), shading the extent of minimum as well as maximum values, and blue line indicates mean values. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/sea-ice-biota" target="_blank">Chapter 3</a> - Page 43 - Figure 3.1.5 From the report draft: "In addition to showing composition and peak abundance ranges, we illustrate the phenology of ice meiofauna over the ice-covered season in the entire combined data set. For this purpose, the data were normalized to the daylight hours at each location during the date of sampling using R package geosphere (Hijmans 2015) and a method described in Forsythe et al. (1995). This was necessary, because ‘spring’ arrives earlier at lower latitudes than at higher latitudes, so that using month or day of year would obscure the pan-Arctic integration of the data. Other influential factors such as snow depth, ice thickness and nutrient concentrations were not accounted for in this analysis."

The Arctic Basin where suggested future long-term monitoring of trawl-megafauna should capture possible changes along the flow of the Arctic Circumpolar Boundary Current (Figure A, blue line) and the Arctic deep-water exchange (Figure b, green line). Adapted from Bluhm et al. (2015). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/benthos" target="_blank">Chapter 3</a> - Page 88 - Figure 3.3.1

Global catches of all capelin species from 1950 to 2011 (FAO 2015). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/marine-fishes" target="_blank">Chapter 3</a> - Page 119 - Figure 3.4.6

Status of monitoring activities for each Focal Ecosystem Component (i.e., selected species groups) across each Arctic Marine Area as included in this report. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/monitoring-status-and-advice" target="_blank">Key Findings</a> - Page 5 - Figure 1