Background information on marine mammals for Strategic Environmental Assessment 6 P.S. Hammond, S.P. Northridge, D. Thompson, J.C.D. Gordon, A.J. Hall, G. Aarts & J. Matthiopoulos Sea Mammal Research Unit Gatty Marine Laboratory University of St Andrews St Andrews, Fife KY16 8LB May 2005 Table of Contents Non-technical summary 4 1. DISTRIBUTION AND ABUNDANCE 9 1.1 Introduction.........................................................................................................................................9 1.2 Baleen Whales.....................................................................................................................................9 1.2.1 Minke whale Balaenoptera acutorostrata ...................................................................................9 1.3 Toothed whales .................................................................................................................................10 1.3.1 Harbour porpoise Phocoena phocoena .....................................................................................10 1.3.2 Risso’s dolphin Grampus griseus .............................................................................................10 1.3.3 Short-beaked common dolphin Delphinus delphis ....................................................................10 1.3.4 Bottlenose dolphin Tursiops truncatus .....................................................................................11 1.4 Other species.....................................................................................................................................12 1.4.1 Fin whale Balaenoptera physalus ..............................................................................................12 1.4.2 Long-finned pilot whale Globicephala melas............................................................................12 1.4.3 Killer whale Orcinus orca..........................................................................................................12 1.5 Pinnipeds...........................................................................................................................................12 1.5.1 Grey seal Halichoerus grypus....................................................................................................12 1.5.2 Harbour (or common) seal Phoca vitulina.................................................................................13 2. ECOLOGICAL IMPORTANCE 13 2.1 Cetaceans..........................................................................................................................................13 2.1.1 Minke whale...............................................................................................................................13 2.1.2 Harbour porpoise........................................................................................................................13 2.1.3 Risso’s dolphin..........................................................................................................................13 2.1.4 Short-beaked common dolphin ..................................................................................................13 2.1.5 Bottlenose dolphin .....................................................................................................................14 2.1.6 Other species.............................................................................................................................14 2.2 Grey seal ...........................................................................................................................................14 2.2.1 Diet composition........................................................................................................................14 2.2.2 Prey consumption.......................................................................................................................14 2.2.3 Foraging movements and distribution........................................................................................14 2.3 Harbour seal .....................................................................................................................................15 2.3.1 Diet composition........................................................................................................................15 2.3.2 Prey consumption.......................................................................................................................15 2.3.3 Foraging movements and distribution........................................................................................15 3. SENSITIVITY TO DISTURBANCE, CONTAMINATION AND DISEASE 16 3.1 Noise .................................................................................................................................................16 3.1.1 Effects of man-made sounds on marine mammals.....................................................................16 3.1.2 Responses of marine mammals to different types of noise........................................................23 3.1.3 Research Requirements..............................................................................................................27 3.2 Contaminants ....................................................................................................................................28 3.2.1 Background ................................................................................................................................28 3.2.2 Sources of Data ..........................................................................................................................29 3.2.3 Knowledge .................................................................................................................................30 3.2.4 Gaps in knowledge.....................................................................................................................32 3.3 Disease..............................................................................................................................................32 2 3.3.1 Background ................................................................................................................................32 3.3.2 Sources of data...........................................................................................................................33 3.3.3 Knowledge .................................................................................................................................33 3.3.4 Gaps in Knowledge....................................................................................................................34 4. BYCATCH AND OTHER NON-OIL MANAGEMENT ISSUES 36 4.1 Bycatch..............................................................................................................................................36 4.2 Other issues.......................................................................................................................................36 5. CONSERVATION FRAMEWORKS 36 5.1 Cetaceans..........................................................................................................................................36 5.1.1 Europe ........................................................................................................................................36 5.1.2 UK..............................................................................................................................................37 5.2 Seals ..................................................................................................................................................37 5.2.1 Europe ........................................................................................................................................37 5.2.2 UK..............................................................................................................................................37 6. CONCLUSIONS 38 References 39 3 Background information on marine mammals for Strategic Environmental Assessment 6 This document was produced as part of the UK Department of Trade and Industry's offshore energy Strategic Environmental Assessment programme. The SEA programme is funded and managed by the DTI and coordinated on their behalf by Geotek Ltd and Hartley Anderson Ltd. Crown Copyright, all rights reserved Non-technical summary Distribution and abundance Seven marine mammal species are known to occur regularly in this area: grey seal, harbour seal, harbour porpoise, short-beaked common dolphin, bottlenose dolphin, Risso’s dolphin and minke whale. There is extensive information on the distribution and abundance of grey and harbour seals around Britain from annual aerial surveys of breeding colonies and haul-out sites and an increasing body of data from satellite telemetry studies. Information on cetacean distribution comes from both dedicated and opportunistic sightings surveys made by a wide spectrum of organisations, some voluntary and some funded by industry and by governmental agencies. There are estimates of abundance only for bottlenose dolphins associated with the Cardigan Bay SAC (213; 95% CI 183-279), and for harbour porpoises in the same area (122; 95% CI 90-165). Harbour seals in the SEA6 area are concentrated along the coast of Northern Ireland and in the Firth of Clyde. The number of animals in the area is likely to be around 3,500-4,000, concentrated in the far north, out of a total UK population of 50-60,000. Harbour