Shetland Inshore Fish Survey (SIFS) 2023:summary of catch rates, size compositions, and spatial distributions of commercial demersal fish species

• Main Authors: Fraser, Shaun, Angus, Chevonne, McAllister, Mia, Thomason, Louise, Ayres, Sarah, Harlow, Leander
• Format: Book
• Language: English
• Published: 2023
• Subjects: Gadus morhua
• Online Access: https://pure.uhi.ac.uk/en/publications/ed8e5cb7-1bf7-43ed-b5ef-bed9d01ccba3; https://pureadmin.uhi.ac.uk/ws/files/49222567/Fraser_et_al._2023._SIFS_report.pdf

An overview of results from the Shetland Inshore Fish Survey (SIFS) conducted by UHI Shetland (formerly NAFC Marine Centre) from 2011 - 2023 in the coastal waters around Shetland is presented. The purpose of the survey is to provide independent information on the distribution, relative abundance, and population structure of fish species in local waters. Key results from the available data are reported here with a focus on commercially important species. This report is intended for a general audience with information presented in a concise and non-technical format. The survey has been carried out annually using the 12 m MFV Atlantia II (LK 502) during August and September, using a standardised survey trawl fitted with a small-mesh (20 mm) cod-end. The original annual inshore fish survey involves hauls from 27 pre-defined locations within 12 nautical miles of Shetland. Since 2017, a concurrent shallow-water fish survey has been added, with up to 25 hauls targeting potential nursery grounds around the coast of Shetland. Catch rate results are used to investigate the relative abundance of commercial species by considering catch per unit effort (CPUE). Length data are used to further interpret variations in population structure and recruitment. Results are presented for the most significant commercially important demersal fish species sampled throughout the surveys. Key findings from the 2023 surveys include: • Haddock (Melanogrammus aeglefinus) continues to be the main component of catches and was characterised this year by mostly marketable size classes that were evenly distributed across inshore grounds, with also a considerable younger age-class present that has not yet recruited into the fishery. • Squid (Lologi spp.) catch rate (by weight) on shallow grounds in 2023 surpassed the record levels observed last year and were concentrated in specific nearshore areas. • Cod (Gadus morhua) catch rate (by weight) on inshore grounds were at their highest level since 2018 with highest cod catches mostly observed in ...