Crab and Lobster Fisheries in Scotland: Results of Stock Assessments 2013-2015

• Main Author: Mesquita C. MSS
• Format: Article in Journal/Newspaper
• Language: English
• Published: Marine Scotland Science 2017
• Subjects: Fish and shellfish catch statistics; Shellfish abundance and biomass in water bodies; Homarus gammarus
• Online Access: https://dx.doi.org/10.7489/1990-1; https://data.marine.gov.scot/dataset/crab-and-lobster-fisheries-scotland-results-stock-assessments-2013-2015

This report presents the results of Scottish regional brown crab (Cancer pagurus), velvet crab (Necora puber) and lobster (Homarus gammarus) stock assessments carried out by Marine Scotland Science (MSS) based on length cohort analyses (LCAs) applied to commercial length frequency data for the period 2013-15. Associated data are presented for download. : With the exception of Shetland, limited effort data (pots fished) has been collected from creel fisheries although recent changes in the FISH1 form may improve data availability for vessels under 10 m. For larger offshore vessels, VMS data integrated with logbook landings could potentially be used to obtain indicators of landings-per-unit-effort and provide information on stock dynamics. • Discards in crab and lobster fisheries are sampled only on an irregular basis. More regular sampling and information on catches of undersized animals could provide an indication of inter-annual variation in recruitment. • The population structure and some aspects of the biology of crab and lobster are not well understood and some of the assessment areas as currently defined may be inappropriate. Brown crab tagging studies are currently underway in Orkney and these may shed light on potential links between the offshore stock at Sule and inshore Orkney stock. • Given the sensitivity of LCAs to the input growth parameters, further work in this area is required. Field studies based on tagging methods and subsequent evaluation of parameters would be desirable. • Information on factors affecting catchability such as bait type, creel density and soak time could be collected by engaging with fishers and industry. Work being conducted within the SIFIDS projects may provide an improved understanding of the drivers of fishing behaviour.