A Review of the Direct and Indirect Impacts of Fishing Activities on Marine Mammals in Welsh Waters
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A Review of the Direct and Indirect Impacts of Fishing Activities on Marine Mammals in Welsh Waters Peter GH Evans & Kirsten Hintner CCW Policy Research Report No. 12/5 © CCGC/CCW March 2013 You may use and reproduce this document free of charge for non-commercial and internal business purposes, except where other copyright is stated. You may reproduce it in any format or medium, provided that you do so accurately, acknowledging both the source and CCW's copyright, and do not use it in a misleading context. This is a report of research commissioned by CCW. However, the views and recommendations presented in this report are not necessarily those of CCW and should, therefore, not be attributed to CCW. Report Number: 12/5 Publication Date: March 2013 Contract Number: 230 EPG 09 Nominated Officer(s): Clare Eno and Mandy McMath Title: Review of the direct and indirect impacts of fishing activities on marine mammals in Welsh waters Author(s): Evans, P.G.H. and Hintner, K. Restrictions: None Distribution List: CCW HQ Library (x2) National Library of Wales Welsh Government Library British Library Recommended Citation: Evans, P.G.H. and Hintner, K. (2012) A Review of the Direct & Indirect Impacts of Fishing Activities on Marine Mammals in Welsh waters. CCW Policy Research Report No. 12/5: 1-172. Review of the Direct and Indirect Impacts of Fishing Activities on Marine Mammals in Welsh Waters Peter G.H. Evans & Kirsten Hintner A Report to Countryside Council for Wales October 2010 Contents List of Contents i List of Figures, tables and charts iv Executive Summary 1 1. Introduction 5 1.1 Project Objectives 5 2. Marine Mammal Species of Wales 7 2.1 Harbour Porpoise 7 2.1.1 Status & Distribution 7 2.1.2 Abundance & Trends 7 2.1.3 Habitat 9 2.1.4 Annual Cycle 9 2.1.5 Diet & Feeding Behaviour 9 2.1.6 Interactions with Humans 10 2.2 Bottlenose Dolphin 13 2.2.1 Status & Distribution 13 2.2.2 Abundance & Trends 13 2.2.3 Habitat 15 2.2.4 Annual Cycle 15 2.2.5 Diet & Feeding Behaviour 15 2.2.6 Interactions with Humans 16 2.3 Short-beaked Common Dolphin 19 2.3.1 Status & Distribution 19 2.3.2 Abundance & Trends 19 2.3.3 Habitat 21 2.3.4 Annual Cycle 22 2.3.5 Diet & Feeding Behaviour 22 2.3.6 Interactions with Humans 23 2.4 Risso’s Dolphin 26 2.4.1 Status & Distribution 26 2.4.2 Abundance & Trends 26 2.4.3 Habitat 26 2.4.4 Annual Cycle 28 2.4.5 Diet & Feeding Behaviour 28 2.4.6 Interactions with Humans 28 2.5 Minke Whale 31 2.5.1 Status & Distribution 31 2.5.2 Abundance & Trends 31 2.5.3 Habitat 31 2.5.4 Annual Cycle 33 2.5.5 Diet & Feeding Behaviour 33 2.5.6 Interactions with Humans 34 2.6 Grey Seal 36 2.6.1 Status & Distribution 36 i 2.6.2 Abundance & Trends 36 2.6.3 Habitat 36 2.6.4 Annual Cycle 37 2.6.5 Diet & Feeding Behaviour 37 2.6.6 Interactions with Humans 39 2.7 River Otter 39 2.8 Biodiversity Patterns 40 3. Welsh Fisheries 42 3.1 Overview of offshore fisheries 46 3.2 Overview of inshore fisheries 48 3.3 Types and distribution of fishing activities in Wales 48 3.3.1 Beam Trawls 48 3.3.2 Scallop Dredgers 50 3.3.3 Rockhopper Trawls 53 3.3.4 Oyster/Mussel Dredging and Prospecting 53 3.3.5 Demersal trawls 53 3.3.6 Light Demersal Trawls and Seines 55 3.3.7 Hydraulic Suction Dredges 56 3.3.8 Pelagic Trawls, Nets and Lines 56 3.3.9 Static Gear - Nets and Long lines 57 3.3.10 Long lines 58 3.3.11 Static Gear – Pots 58 3.3.12 Rod and Line hand-fishing 63 3.3.13 Casual hand gathering 63 3.3.14 Professional hand gathering 64 3.3.15 Aquaculture - Trestles, Ground lays & Traps 64 3.3.16 Aquaculture - Cages & Rope Cultivation 65 3.3.17 Suspended Rope Aquaculture 65 3.4 Summary and Conclusions 65 4. Fisheries and their direct impacts on marine mammals 66 4.1 Trawls 68 4.1.1 Demersal Trawls 68 4.1.2 Pelagic Trawls 70 4.2 Static Fishing Gear 75 4.2.1 Bottom-Set Gillnets and Tangle Nets 75 4.3 Static Gear (Fixed Gear) – Long lines, Pots & Traps 83 4.3.1 Long line fishing 83 4.3.2 Fixed Nets, Pots & Traps 84 4.4 Driftnets 85 4.5 Seine nets 87 4.6 Recreational fishing & “ghost fishing” 88 4.7 Mesh Types 89 4.8 Management of Marine Mammal By-catch 90 4.9 Noise Disturbance from Fishing Activities 90 4.10 Ship strikes 91 4.11 Summary and Conclusions 91 5. Mitigation Measures for the Reduction of By-catch 92 ii 5.1 Introduction 92 5.2 Legislative instruments 93 5.3 Mitigation measures 94 5.4 Monitoring of fisheries 97 5.5 Summary and Conclusions 99 6. Review of Indirect Impacts of Fisheries on Marine Mammals 100 7. Effects of Fishing Activities on Marine Mammal Behaviour and Activity in Welsh waters 104 7.1 Direct Impacts upon Marine Mammals in Welsh Waters 104 7.2 Indirect Impacts upon Marine Mammals in Welsh Waters 112 8. Acknowledgements 114 10. Bibliography 115 Appendix 1: Categories of Fishing Activities Used by CCW 144 Appendix 2: Details of the Diet of Marine Mammals 145 Appendix 3: Summary of Fisheries and By-catch Information for North West Europe 160 Appendix 4: Trends in Causes of Death for UK Harbour Porpoise and Short-beaked Common Dolphin, 1991-2010 163 iii List of Figures Figure 1: Long-term mean sightings rates (counts per hour) of harbour porpoise 8 Figure 2: The diet of harbour porpoise by number (%) in the Northeast Atlantic 11 Figure 3: The diet of harbour porpoise by weight (%) in the Northeast Atlantic 12 Figure 4: Long-term sightings rates (no. of individuals per hour) of bottlenose dolphin 14 Figure 5: The diet of bottlenose dolphins by number (%) in the Northeast Atlantic 17 Figure 6: The diet of bottlenose dolphins by weight (%) in the Northeast Atlantic 18 Figure 7: Long-term sightings rates (sightings per hour) of common Dolphin 20 Figure 8: The diet of short-beaked common dolphins by number (%) in the Northeast Atlantic 24 Figure 9: The diet of short-beaked common dolphins by weight (%) in the Northeast Atlantic 25 Figure 10: Long-term sightings rates (sightings per hour) of Risso’s Dolphin 27 Figure 11: The diet of Risso’s dolphins by number (%) in the Northeast Atlantic 29 Figure 12: The diet of Risso’s dolphins by weight (%) in the Northeast Atlantic 30 Figure 13: Long-term sightings rates (sightings per hour) of minke whale 32 Figure 14: The diet of minke whales by weight (%) in the Northeast Atlantic 35 Figure 15: Sightings rates of grey seals, 1990–2007 38 Figure 16: The diet of grey seals by weight (%) in the Northeast Atlantic 39 Figure 17: ICES Areas 42 Figure 18: Map showing 1,3,6 % 12nm boundaries & SACs in Welsh waters 43 Figure 19: Extent of Area SEA6 46 Figure 20: Annual distribution of beam trawling within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 49 Figure 21: Distribution of beam (Cumbria, Lancashire, North & SW Wales) & Nephrops (between Northern Ireland and the Isle of Man) trawls from VMS, 2007 49 Figure 22: Quarterly distribution of beam trawling within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 50 Figure 23: Annual distribution of scallop dredging within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 51 Figure 24: Quarterly distribution of scallop dredging within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 51 Figure 25: Distribution of dredging effort from VMS, 2007 52 Figure 26: Distribution of scallop dredging effort in Cardigan Bay, 2008 52 Figure 27: Annual distribution of otter trawling within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 54 Figure 28: Distribution of trawling effort from VMS, 2007: a) Pelagic otter trawls; b) Demersal otter trawls 54 iv Figure 29: Quarterly distribution of otter trawling within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 55 Figure 30: Distribution of bottom set gillnetting in the Irish Sea, 2007 56 Figure 31: European lobster & static gear-pots 59 Figure 32: Annual landings of edible, spider & velvet crab 60 Figure 33: Annual landings of lobster 60 Figure 34: Annual distribution of potting within SEA6 between 1998 and 2003 based on SFI overflight surveillance data 61 Figure 35: Distribution of potting from VMS, 2007 61 Figure 36: Quarterly distribution of potting within SEA6 between 1998 And 2003 based on SFI overflight surveillance data 62 Figure 37: Evidence of by-catch in stranded animals 67 Figure 38: Beam Trawling 69 Figure 39: Otter Trawling 69 Figure 40: Pair Trawling 70 Figure 41: Atlantic white-sided dolphin from a pelagic trawl 71 Figure 42: Outline Representing Bottom-set Gill Net or Tangle Net 75 Figure 43: Number and percentage of stranded porpoises that were diagnosed as having been by-caught in Belgium between 1995-2007 79 Figure 44: Total number of stranded animals in Belgium diagnosed as having been by-caught per month between 1995-2007 79 Figure 45: Increase of porpoise strandings on the north French Belgium and Dutch coasts between 2000-2006 80 Figure 46: Harbour porpoise captured in recreational fishery in Shetland 81 Figure 47: Minke whale entangled in creel line in the Hebrides 85 Figure 48: Purse Seine 87 Figure 49: Minke whale entangled in fishing net 89 Figure 50: Different types of net used by gillnet fishermen 89 Figure 51: Pinger devices shown on a tangle net and a gillnet 93 Figure 52: Pinger entangled in fishing gear and durability of pingers is an issue 95 Figure 53: Exclusion devices 96 Figure 54: Proportions of major cause of death catagories in UK stranded harbour porpoises examined at post mortem 2004-2008 104 Figure 55: Annual proportion of stranded harbour porpoises diagnosed to be killed by bottlenose dolphins and by-caught in Wales 105 Figure 56: Spatial distribution of cetacean