A preliminary assessment of endangered sei whales ( Balaenoptera borealis ) in two candidate Key Biodiversity Areas in West Falkland Author: Dr Caroline Weir, Sei Whale Project Officer Produced by: Falklands Conservation, Jubilee Villas, Ross Road, Stanley, Falkland Islands Version: 1.2 Date: 3 September 2018 1 CONTENTS Contents .................................................................................................................................................. 2 Acronyms ................................................................................................................................................ 5 Non-Technical Summary ........................................................................................................................ 6 1. Introduction ................................................................................................................................... 10 1.1. Rationale ............................................................................................................................... 10 1.2. Report format ........................................................................................................................ 11 1.3. Research permits ................................................................................................................... 11 2. Aims and Objectives ..................................................................................................................... 12 3. Study Area .................................................................................................................................... 13 4. Preliminary Survey ....................................................................................................................... 16 4.1. Introduction and aims ........................................................................................................... 16 4.2. Methods................................................................................................................................. 16 4.3. Results ................................................................................................................................... 17 4.4. Discussion ............................................................................................................................. 18 5. Visual Sighting Survey ................................................................................................................. 20 5.1. Introduction and aims ........................................................................................................... 20 5.2. Methods................................................................................................................................. 20 5.2.1. Visual survey methods .................................................................................................. 20 5.2.2. Transect survey ............................................................................................................. 22 5.2.3. Non-systematic sighting survey .................................................................................... 23 5.2.4. Data analysis ................................................................................................................. 24 5.3. Results ................................................................................................................................... 25 5.3.1. Overview ....................................................................................................................... 25 5.3.2. Transect survey ............................................................................................................. 25 5.3.3. Non-systematic sighting survey .................................................................................... 28 5.3.4. Combined search effort ................................................................................................. 28 5.3.5. Cetacean sightings......................................................................................................... 31 5.4. Human activities ................................................................................................................... 47 5.5. Discussion ............................................................................................................................. 53 6. Photo-Identification ...................................................................................................................... 55 6.1. Introduction and aims ........................................................................................................... 55 6.2. Methods................................................................................................................................. 55 6.2.1. Field methods ................................................................................................................ 55 2 6.2.2. Catalogue compilation .................................................................................................. 56 6.2.3. Data analysis ................................................................................................................. 60 6.3. Results ................................................................................................................................... 60 6.3.1. Overview ....................................................................................................................... 60 6.3.2. West Falkland study ...................................................................................................... 62 6.3.3. Comparison with Berkeley Sound ................................................................................ 65 6.4. Discussion ............................................................................................................................. 68 7. Behavioural Study ......................................................................................................................... 72 7.1. Introduction and aims ........................................................................................................... 72 7.2. Methods................................................................................................................................. 73 7.2.1. Data collection .............................................................................................................. 73 7.2.2. Data analysis ................................................................................................................. 73 7.3. Results ................................................................................................................................... 74 7.3.1. Overview ....................................................................................................................... 74 7.3.2. Cue rates ........................................................................................................................ 76 7.3.3. Dive duration ................................................................................................................ 76 7.3.4. Dive types ..................................................................................................................... 77 7.4. Discussion ............................................................................................................................. 77 8. Faecal Sampling ............................................................................................................................ 82 8.1. Introduction and aims ........................................................................................................... 82 8.2. Methods................................................................................................................................. 82 8.3. Results ................................................................................................................................... 84 8.4. Discussion ............................................................................................................................. 85 9. Bone Sampling .............................................................................................................................. 87 9.1. Introduction and aims ........................................................................................................... 87 9.2. Methods................................................................................................................................. 87 9.3. Results ................................................................................................................................... 90 9.4. Discussion ............................................................................................................................. 90 10. Acoustic Feasability Study........................................................................................................ 91 10.1. Introduction and aims........................................................................................................ 91 10.2. Methods ............................................................................................................................. 93 10.2.1. SoundTrap ..................................................................................................................... 93 10.2.2. Dip hydrophone............................................................................................................