UK fisheries, climate change and North Sea fishes: a long-term perspective Tina Katharina Kerby A thesis submitted for the degree of Doctor of Philosophy University of East Anglia, Norwich, UK School of Environmental Sciences July 2013 © This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and that use of any information derived therefrom must be in accordance with current UK Copyright Law. In addition, any quotation or extract must include full attribution. Learning about the past is important because it will help us determine our future J. Jackson, J. Jacquet (The shifting baselines syndrome: perception, deception, and the future of our oceans. In V. Christensen, J. Maclean (Eds.), Ecosystem approaches to fisheries: a global perspective. Cambridge University Press, 2011) Contents Abstract ............................................................................................................................................ I Acknowledgements ........................................................................................................................ II Chapter 1 ......................................................................................................................................... 1 Introduction 1.1 The North Sea ................................................................................................................... 2 1.2 North Sea fish .................................................................................................................... 3 1.3 North Sea fisheries ............................................................................................................ 4 1.4 Factors affecting fish distributions .................................................................................... 5 1.5 The shifting baseline phenomenon .................................................................................... 6 1.6 Historical fisheries data ..................................................................................................... 7 1.6.1 Research initiatives ........................................................................................................... 7 1.6.2 Cefas .................................................................................................................................. 8 1.6.3 ICES .................................................................................................................................. 9 1.6.3.1 Commercial fisheries data ................................................................................................ 9 1.6.3.2 Research survey data ...................................................................................................... 10 1.7 Thesis outline .................................................................................................................. 11 1.7.1 Research context ............................................................................................................. 11 1.7.2 Objectives of the thesis ................................................................................................... 12 1.7.3 Thesis structure ............................................................................................................... 12 1.8 References ....................................................................................................................... 13 Chapter 2 ....................................................................................................................................... 20 The United Kingdom’s role in North Sea demersal fisheries: a hundred year perspective 2.1 Abstract ........................................................................................................................... 21 2.2 Introduction ..................................................................................................................... 21 2.3 Data ................................................................................................................................. 22 2.4 North Sea demersal landings in the twentieth century .................................................... 23 2.5 Technological drivers ...................................................................................................... 25 2.5.1 Vessel improvements ...................................................................................................... 25 2.5.2 Large scale modern fisheries ........................................................................................... 30 2.5.3 Fishing gear ..................................................................................................................... 31 2.6 Economical drivers: demand and supply of seafood ....................................................... 32 2.7 Legislation and political events ....................................................................................... 33 2.7.1 Fishing without restrictions and the effects of two wars ................................................. 33 2.7.2 The ‘Cod Wars’ and fishing limits .................................................................................. 34 2.7.3 Sharing resources: the European Union and the Common Fisheries Policy ................... 35 2.7.4 Adjustment and change in the fishery of the United Kingdom ....................................... 36 2.8 Conclusions ..................................................................................................................... 37 2.9 References ....................................................................................................................... 39 Chapter 3 ....................................................................................................................................... 46 Wondering about wandering whiting: distribution of North Sea whiting between the 1920s and 2000s 3.1 Abstract ........................................................................................................................... 47 3.2 Introduction ..................................................................................................................... 47 3.3 Material and Methods...................................................................................................... 49 3.3.1 Fisheries data ................................................................................................................... 49 3.3.2 Distribution of British whiting landings in the North Sea .............................................. 50 3.3.3 Analysis of the spatial distribution of whiting ................................................................ 50 3.3.4 Whiting distribution shift in relation to climate variables and fishing pressure ............. 52 3.4 Results ............................................................................................................................. 54 3.4.1 Long-term landing trends of international North Sea whiting fisheries .......................... 54 3.4.2 Distribution of whiting landings by British fisheries ...................................................... 56 3.4.3 Nine decades of whiting distribution .............................................................................. 58 3.4.4 Correlations of distribution shifts with environmental and fishing variables ................. 61 3.5 Discussion ....................................................................................................................... 63 3.5.1 Lack of deepening and latitudinal shifts ......................................................................... 64 3.5.2 The longitudinal shift of whiting ..................................................................................... 65 3.5.3 Influence on distribution patterns .................................................................................... 66 3.5.4 Challenges of commercial fisheries data ......................................................................... 67 3.6 Conclusions ..................................................................................................................... 67 3.7 References ....................................................................................................................... 68 Chapter 4 ....................................................................................................................................... 76 The catching and landing in demersal fisheries: a comparison between commercial fisheries data and research survey data for whiting distribution in the North Sea 4.1 Abstract ........................................................................................................................... 77 4.2 Introduction ..................................................................................................................... 77 4.3 Material and Methods...................................................................................................... 80 4.3.1 Sources of commercial fisheries and research survey data ............................................. 80 4.3.2 Distribution analysis for commercial and survey data .................................................... 80 4.3.3 Examining discrepancies in whiting distribution between commercial and survey data 81 4.3.4 Revenue-per-unit-effort of more valuable fish species ................................................... 81 4.4 Results ............................................................................................................................