Pelagic Fish at the Barents Sea Polar Front in August 2023

Abstract

## Methods ### Study area This dataset is the result of sampling at nine stations at the Polar Front, in the western part of the Barents Sea. Some stations were sampled twice at different depths. ### Time coverage The samples were collected between 16 August 2023 and 25 August 2023. ### Sampling 15 pelagic trawl samples were collected with a Harstad pelagic trawl, which has an effective opening of 80 m2 when towed at ca. 3 knots. The mesh size of the inner liner of the cod end was 10 mm. The pelagic trawl was towed at ca. 3 knots for 20-30 min at the target depth and abundances were standardized by converting to catch per unit effort (expressed in kilograms per cubic meter). ### Sample analysis All organisms were identified, when possible to to species level, otherwise to the lowest taxonomic rank possible by visual identification onboard. Capelin had a large size distribution, so individuals similar in length were sorted into approximate size classes (small, medium, and large). The total number and weight of each species was recorded. For large catches, subsamples of 20-30 individuals were taken as a representation of the length distributions of the catch. The standard length, height at the anus (up to the nearest 1 mm), and weight (up to the nearest 0.1 g) were measured for all specimens caught and those in the subsample for abundant species. ### Data management While the PolarFront project publishes all its data on Zenodo, biological diversity datasets are also published in the Global Biodiversity Information Facility (GBIF). The data is prepared using the international Darwin Core (DwC) vocabulary (https://dwc.tdwg.org/) and is distributed as DwC text files that follows GBIF's [data quality requirements](https://www.gbif.org/data-quality-requirements-sampling-events) and [best practices for sampling event datasets](https://ipt.gbif.org/manual/en/ipt/latest/best-practices-sampling-event-data). Prior to publishing all data files are validated using GBIF's data validator (https://www.gbif.org/tools/data-validator). Taxonomy is also validated against the [GBIF API](https://techdocs.gbif.org/en/openapi/v1/species) and [World Register of Marine Species](https://www.marinespecies.org).