Acoustic analysis of slow click function and foraging in sperm whales (Physeter macrocephalus) off Kaikoura, New Zealand By Manuel Goulartt de Medeiros de Carvalho Fernandes A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy in Zoology at the University of Canterbury New Zealand December 2016 ii Table of contents Table of contents .................................................................................................................................................... 1 Abstract................................................................................................................................................................... 5 Acknowledgments .................................................................................................................................................. 7 1. General introduction ................................................................................................................................. 11 1.1. Sperm whale life history ...................................................................................................................... 11 1.2. Social structure and sexual segregation ............................................................................................. 12 1.3. Diet and foraging behaviour ............................................................................................................... 14 1.4. Sperm whale acoustics ........................................................................................................................ 15 1.5. Kaikoura feeding ground .................................................................................................................... 18 1.6. Thesis overview ................................................................................................................................... 19 1.7. References ........................................................................................................................................... 20 2. A function analysis of male sperm whale slow clicks on a male-only foraging habitat ........................ 27 Abstract................................................................................................................................................................. 27 2.1. Introduction ......................................................................................................................................... 28 2.2. Methods ............................................................................................................................................... 31 2.2.1. Field work ....................................................................................................................................... 31 2.2.2. Acoustic hardware .......................................................................................................................... 33 2.2.3. Photo-identification ........................................................................................................................ 34 2.2.4. Acoustic data .................................................................................................................................. 35 2.2.5. Data extraction ............................................................................................................................... 35 2.2.6. Statistical analyses .......................................................................................................................... 39 2.3. Results ................................................................................................................................................. 41 2.3.1. General patterns ............................................................................................................................. 41 2.3.2. Slow clicks at start of dive .............................................................................................................. 46 2.3.3. Slow click events ............................................................................................................................. 48 2.3.4. Slow click echoes ............................................................................................................................ 49 2.4. Discussion ........................................................................................................................................... 51 2.4.1. General ........................................................................................................................................... 51 2.4.2. Slow clicks as communication ........................................................................................................ 52 2.4.3. Slow clicks as echolocation ............................................................................................................ 54 2.5. References ........................................................................................................................................... 57 1 3. Slow click structure and its relationship to body size and directionality .............................................. 61 Abstract................................................................................................................................................................. 61 3.1. Introduction ......................................................................................................................................... 62 3.2. Methods ............................................................................................................................................... 65 3.2.1. Field work ....................................................................................................................................... 65 3.2.2. Estimating body length from regular clicks .................................................................................... 65 3.2.3. Estimating body length from slow clicks......................................................................................... 66 3.2.4. Spectral analysis of slow clicks ....................................................................................................... 66 3.2.5. Slow click pulse structure ............................................................................................................... 68 3.2.6. Statistical analyses .......................................................................................................................... 70 3.3. Results ................................................................................................................................................. 71 3.3.1. Estimating body length from regular clicks .................................................................................... 71 3.3.2. Estimating body length from slow clicks......................................................................................... 71 3.3.3. Spectral analysis of slow clicks ....................................................................................................... 72 3.3.4. Slow click pulse structure ............................................................................................................... 77 3.4. Discussion ........................................................................................................................................... 79 3.5. References ........................................................................................................................................... 83 4. Synchronised surfacing: codas, slow clicks and long-term bonds ......................................................... 89 Abstract................................................................................................................................................................. 89 4.1. Introduction ......................................................................................................................................... 90 4.2. Methods ............................................................................................................................................... 93 4.2.1. Data collection and analysis ........................................................................................................... 93 4.3. Results ................................................................................................................................................. 95 4.3.1. Available data ................................................................................................................................. 95 4.3.2. Brief description of the field observation ........................................................................................ 95 4.3.3. Overview ......................................................................................................................................... 97 4.3.4. Coda-creaks .................................................................................................................................... 98 4.3.5. Spectral frequency analysis of coda and slow clicks ...................................................................... 98 4.3.6. ‘Coda codas’ and ‘slow click codas’ ............................................................................................ 101 4.3.7. Slow clicks and Codas .................................................................................................................