Title Page
ABSTRACT
Contents
1. INTRODUCTION 14
2. MATERIALS AND METHODS 18
2.1. Data collection and processing 18
2.1.1. Acoustic data 23
2.1.2. Vessel GPS and environmental data sets 24
2.2. Statistics test 25
3. RESULTS 27
4. DISCUSSION 47
4.1. Relative power in Terra Nova Bay Polynya 48
4.2. Anti-masking behavior of leopard seals 49
5. CONCLUSIONS 52
7. REFERENCES 54
Table 1. The mooring location of hydrophones, depth, deployment period and selected period of each year from 2016 to 2018. 21
Table 2. The signal characteristics of leopard seal vocalizations from PALAOA repositories and in this study. The four vocalizations were identified... 22
Table 3. The results of generalized linear model (GLM) test described by Poisson distribution for vocalization frequency as a dependent variable and... 45
Table 4. The results from Likelihood ratio test (LRT) with vocalization frequency as a dependent variable and explanatory variables. LRT was... 46
Figure 1. The mooring site for autonomous hydrophone system near Terra Nova Bay Polynya (TNBP). From 2016 to 2018, hydrophones (displayed by... 19
Figure 2. The schematic diagram of instrument system which including NOAA Autonomous hydrophone which is called HARUphone using in this... 20
Figure 3. Relative power of the 100-125 band (gray shaded area labeled by 'Ship') and the 300-350 band (yellow shaded area labeled by 'Ship+Vocal')... 30
Figure 4. Relative power of the 100-125 band (gray shaded area labeled by 'Ship') and the 300-350 band (yellow shaded area labeled by 'Ship+Vocal')... 31
Figure 5. Relative power of the 100-125 band (gray shaded area labeled by 'Ship') and the 300-350 band (yellow shaded arealabeled by 'Ship+Vocal')... 32
Figure 6. Spectrogram indicates the four type of leopard seal vocalizations in Terra Nova Bay Polynya visualizing by Python. All of vocalizations identified... 33
Figure 7. The Sea ice concentration near Drigalski Ice Tongue (DIT) and route of 2016 first summer voyage of IBRV Araon. Vessel GPS track displayed with distance between hydrophone and vessel (blue). (A) sea ice was found relatively... 34
Figure 8. Spectrogram of 2016 first summer voyage of IBRV Araon on Terra Nova Bay Polynya. In-way voyage period shows in November 27 and out-way voyage period shows in December 2. Color of the... 35
Figure 9. The Sea ice concentration near Drigalski Ice Tongue (DIT) and route of 2017 first summer voyage of IBRV Araon. Vessel GPS track displayed with distance between hydrophone and vessel (blue). Sea ice was found relatively... 36
Figure 10. Spectrogram of 2017 first summer voyage of IBRV Araon on TNBP. In-way voyage period shows in December 3 and out-way voyage period shows in December 7. Color of the spectrogram represents the power spectral... 37
Figure 11. The Sea ice concentration near Drigalski Ice Tongue (DIT) and route of 2018 first summer voyage of IBRV Araon. Vessel GPS track displayed with distance between hydrophone and vessel (blue). Sea ice was absent during both... 38
Figure 12. Spectrogram of 2018 first summer voyage of IBRV Araon on TNBP. In-way voyage period shows in December 2 and out-way voyage period shows in December 7. Color of the spectrogram represents the power spectral... 39
Figure 13. The seal vocalization frequency of in-way and out-way group of each season. Horizontal line in the box shows median value. Upper margin of... 40
Figure 14. The predicted curves (Red) and confidence intervals (shaded area) for vocalization frequency and Euclidean distance between hydrophone and... 41
Figure 15. Seal vocalization frequency is increasing when wind speed is increasing near Jang Bogo station computed by Poisson regression in... 42
Figure 16. Seal vocalization frequency is increasing when sea ice concentration on the vessel route is decreasing near Terra Nova Bay Polynya... 43
Figure 17. Seal vocalization frequency of each periodic group in each season. In 2016, seal vocalization frequency in both period of (A) in-way period (B)... 44