Shetland Shellfish Stock Assessments 2021: A report prepared for the Shetland Shellfish Management Organisation (SSMO)

This report details the Shetland shellfish stock assessment and contains analyses of data collected by UHI Shetland staff, together with information from Shetland Shellfish Management Organisation (SSMO) logbooks. The data has been collected since 2000 and covers the main commercial shellfish species included in the Shetland Islands Regulated Fishery (Scotland) Order 1999: velvet crab (Necora puber), brown crab (Cancer pagurus), green crab (Carcinus maenas), European lobster (Homarus gammarus), common whelk (Buccinum undatum), king scallop (Pecten maximus), and queen scallop (Aequipecten opercularis).
Shellfish fisheries and the inshore fleet are an extremely important part of the Shetland economy. Data show that in 2019 80% of the Shetland fleet was made up of licenced vessels under 10 m (Scottish Sea Fisheries Statistics, 2020). Although the volume of landings is dwarfed by those of the pelagic and demersal fleets, the shellfish fishery remains the most valuable per unit weight with total worth almost£5 million in 2021 (Napier 2021).
The data collected from fishers completing SSMO logbooks provides an extremely detailed and valuable time series of information. Alongside biological data collection, it allows assessments of the stocks to be carried out using a variety of techniques in support of the management system. Data on Landings Per Unit Effort (LPUE) are used as fisheries reference points, as defined by the SSMO. This involves the a priori setting of management responses to varying degrees of change in annual LPUE.