A collaborative study to develop and facilitate a fisher-directed stock assessment of Cancer pagurus in the Inshore Potting Area, south Devon

The financial importance of the south Devon crab fishery was highlight by landings of 17,800 tonnes in 2010 (£18.9 million), approximately 59% of total UK crab landings. In recent years crab landings have increased and as such Bannister (2009) recommended ‘a precautionary approach to future crab fishing’ and ‘the setting of management objectives to prevent any further increase in fishing mortality’. It is the responsibility of the MMO to achieve this as part of the EU target of setting catch limits to accomplish Maximum Sustainable Yield (MSY) in all fisheries by 2020. Despite this aims the authorities responsible for the enforcement measures to achieve MSY are grossly under-resourced. Thus an innovative and inexpensive method to create sustainable small-scale fisheries is a necessity. Therefore the aim of this thesis, as part of the GAP1 and 2 Projects, was to devise a bottom up approach to create a sustainable fishery in south Devon using a fisher-directed stock assessment method and quota system, whilst working collaboratively with local fishers. To achieve this aim we carried out the following objectives. We collected fine-scale data on catch, landings and discards gathered onboard fishing vessels over most of a year and 10 years worth of fisheries diaries this produced spatiotemporal mapping of crab distribution within the IPA. We performed semi-structured interviews answered by a subset of fishers to gather their Fisher Local Ecological Knowledge (FLEK). The results were then compared with empirical data and the scientific literature, which revealed that the FLEK was accurate and valid enabling its use in future management measures. Further we evaluated our approach of collaborative working, identifying the strengths and weaknesses of the style of research. We established guidelines for future researchers and fishers to work collaboratively. The aforementioned data and knowledge was synthesised and evaluated as inputs to the Individual Based Model (IBM) of the fishery that was independently developed by P. J. B. Hart. The IBM currently enables its users to explore how the crab population and the fishery interact, as well as a tool that can be used to better understand the abiotic factors that affect the fluctuations in the fishery. In the future we hope the model will be able to output a sustainable quota of landings for the fishery. Finally, we produced a comprehensive plan of action to implement the future fisher-directed stock assessment and quota system into local management.