Shellfisheries, Seabed Habitats and Interactions in Northumberland
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Shellfisheries, Seabed Habitats and Interactions in Northumberland Fabrice Stephenson School of Marine Science and Technology Newcastle University Submitted to Newcastle University for the degree of Doctor of Philosophy July 2016 i Shellfisheries, Seabed Habitats and Interactions in Northumberland Fabrice Stephenson Supervisors: Dr C Fitzsimmons, Prof N Polunin, Dr A Mill and Dr C L Scott (Natural England) Examiners: Prof M Kaiser and Dr B Wigham Abstract A push for a more evidence based approach to management has resulted in the need for robust evidence of fisheries impacts (or lack thereof), including further research into fine-scale impacts of potting for which little evidence is available. The present work focusses on the inshore pot fishery in Northumberland, UK. Potting effort distribution maps - a combination of fishing vessel sightings recorded during routine patrols and fishing effort by the Northumberland Inshore Fisheries and Conservation Authority (NIFCA) – showed changes in potting effort across large sections of the study area between years (2004 – 2014). Temporal changes in fishers’ habitat selection were investigated using recently collected habitat data. Space-time clustering suggested fishers were actively targeting habitats of interest. Compositional analysis of habitat, showed that fishers preferred rocky habitats over sediment habitats when using both EUNIS level 3 and 6 habitat maps. Information on habitat use and fishing pressure provided the basis for investigation of long-term impacts of parlour potting on epibenthos and habitat within the Berwickshire & North Northumberland Coast European Marine Site (BNNC EMS) through analysis of historical videographic monitoring data between 2002 – 2011. Analysis of biotope change between years (a method recommended for monitoring purposes) showed that at the scales investigated here, change had not occurred. Weaknesses of this analysis for the use in robust ecological research are discussed. A more detailed analysis of community composition and diversity change between years showed that there was little evidence of change. However, changes in species composition and richness of ‘Faunal and algal crusts on exposed to moderately wave-exposed circalittoral rock’ were observed between years, in most models and between fishing pressures. Finally, quantification of direct impacts through in-situ experimental fishing was investigated using a BACI design. The high experimental fishing intensity, in small experimental areas, coupled with high levels of sampling and replication, provided ii robust evidence that current levels of potting are unlikely to have a direct physical impact on epibenthos in Faunal and algal crust, and Laminaria spp dominated habitats in Northumberland. iii Acknowledgements I would like to thank the many people who have provided help, advice and support throughout this PhD. First and foremost, I would like to thank my supervisors Dr Clare Fitzsimmons, Prof Nick Polunin, Dr Aileen Mill and Dr Catherine Scott for their guidance, help and patience. Specifically, I would like to thank Dr Clare Fitzsimmons for her mentoring and the loan of her personal equipment for fieldwork without which much of this research would not have been possible; Prof Nick Polunin and Dr Catherine Scott for helping me develop and concisely express my ideas; and Dr Aileen Mill and Dr Mark Shirley for their statistical advice and help writing code in R. This thesis was the result of a collaborative research project between Newcastle University, Northumberland Inshore Fisheries Conservation Authority and Natural England. I would like to thank Dr Catherine Scott and Dr Clare Fitzsimmons for creating the initial research questions and for finding the time and energy to help obtain funding; Natural England for funding this work and providing me with drop- down video data; the staff of the Northumberland IFCA for providing me with fisheries sightings and landings data, for answering the many questions I had about the Northumberland fishery and for providing advice and support during my fieldwork. I must also thank the staff of the RV Princess Royal: Dr Ben Wigham for making time in the RV schedule for my work and Neil Armstrong and Barry Pearson for providing advice on experimental design, project planning, and showing me how to rig pots and fish them. Many thanks to all the volunteers who helped with early starts and long hours during the diving fieldwork: Paula Lighfoot, Charlie Dryden, Simone Branchini, Catherine Logan, Sierra Ison, Tina Skinner, Dr Chris Sweeting and Dr Steve Newman. Thank you for being supportive and available when plans had to change at the last minute. I would also like to thank everyone from the research group at Newcastle University for their technical help, discussions and distractions. Especially Charlie Dryden, Tina Skinner, Dr Dan Skerritt, Andrew Spencer, Andrew Temple, Paula Lightfoot, Dr Steve Newman and Dr Chris Sweeting. Finally, I would like to thank all my friends in Newcastle who have made my time here truly memorable; all the guys from NCLC United football team (especially, Pepe, Joe, Charlie, Dan, Tom); my family for encouraging me to take on the challenge of doing a PhD; and my wife Gemma for her unwavering support and love. iv v Table of Contents Shellfisheries, Seabed Habitats and Interactions in Northumberland ............................................................................................................... ii Abstract ................................................................................................. ii Table of Contents ................................................................................ vi List of Tables ....................................................................................... xi List of Figures ..................................................................................... xv Acronyms and Symbols .................................................................... xxi Chapter 1 . Impacts and Management of Fishing on Habitat and Benthic Communities ........................................................................... 1 1.1. Introduction .................................................................................................. 1 1.2. Sensitivity of organisms .............................................................................. 2 1.3. General fishing gear impacts ...................................................................... 3 1.4. Impacts of potting on habitat and benthic communities .......................... 5 1.4.1. Nature of potting .................................................................................... 5 1.4.2. Direct impacts ........................................................................................ 6 1.4.2.1. Impacts of pot deployment ................................................................ 6 1.4.2.2. Impacts of pot soak time ................................................................... 7 1.4.2.3. Impacts of hauling pots ..................................................................... 9 1.4.2.4. Evidence of direct impacts from experimental fishing ....................... 9 1.4.3. Indirect potting impacts ...................................................................... 10 1.5. Hierarchical classification systems .......................................................... 12 1.5.1. The marine biotope classification of the United Kingdom ............... 13 1.5.2. Habitat mapping ................................................................................... 15 1.5.3. Critical appraisal of marine biotope classification systems ............ 16 1.6. Methodologies for the assessment of benthic marine environment ..... 18 1.6.1. Videography as a tool for ecological sampling ................................. 18 1.6.2. Critical appraisal of videography methods ....................................... 19 1.7. Fishing effort distribution .......................................................................... 21 1.7.1. Logbook schemes ............................................................................... 22 1.7.2. Vessel monitoring system .................................................................. 23 1.7.3. Surveillance Information – Aerial or at sea observations ................ 23 1.8. Thesis outline and study site .................................................................... 24 1.8.1. European Marine Sites ........................................................................ 25 1.8.2. The Berwickshire & North Northumberland Coast European Marine Site 25 1.8.3. Defra’s revised approach to management of fisheries in European Marine Sites ....................................................................................................... 27 vi 1.8.4. Aims and objectives ........................................................................... 28 Chapter 2 . Decadal Inshore Fishing Activities in Northumberland: Spatial, Temporal Changes ................................................................ 30 2.1. Introduction ................................................................................................ 30 2.2. Methods ...................................................................................................... 31 2.2.1. Observed fishing activity .................................................................... 31 2.2.2. Vessel sightings .................................................................................. 32 2.2.3. Vessel tracks