Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior
This research was carried out in support of fieldwork in the Gulf of Mexico in summers 2004 and 2005 as part of the multidisciplinary Sperm Whale Seismic Study (SWSS). Important aspects of SWSS research include oceanographic habitat characterization and studies of sperm whale foraging and diving pat...
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fttexasamuniv:oai:oaktrust.library.tamu.edu:1969.1/ETD-TAMU-1173 2023-07-16T04:01:01+02:00 Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior Azzara, Alyson Julie Biggs, Douglas DiMarco, Steven Quigg, Antonietta Thode, Aaron 2009-05-15 electronic application/pdf born digital https://hdl.handle.net/1969.1/ETD-TAMU-1173 en_US eng https://hdl.handle.net/1969.1/ETD-TAMU-1173 Deep scattering layer Gulf of Mexico Sperm Whale Book Thesis Electronic Thesis text 2009 fttexasamuniv 2023-06-27T22:23:23Z This research was carried out in support of fieldwork in the Gulf of Mexico in summers 2004 and 2005 as part of the multidisciplinary Sperm Whale Seismic Study (SWSS). Important aspects of SWSS research include oceanographic habitat characterization and studies of sperm whale foraging and diving patterns. During the SWSS 2005 cruise, acoustic volume backscatter data were collected using a 38 kHz ADCP for comparison with XBT, MODIS ocean color data, and whale dive profiles extrapolated from analysis of towed passive acoustic hydrophone array recordings of whale vocalizations. This unique data set, collected from a cyclonic eddy, was compared with non-upwelling conditions surveyed in the western Gulf and the Mississippi Canyon in summer 2004. My focus was to examine the relationship between acoustic backscatter intensity from the deep scattering layer (DSL; usually 400-600 m deep) and the depths to which whales dived. The results of the study investigate differences in DSL characteristics between divergent zones and non-divergent zones, and examine connections relating to variations in sperm whale dive patterns. The analysis of 38 kHz ADCP data showed that there were significant differences in some characteristics of the main DSL dependent on time of day. There were no significant differences in characteristics of the main DSL between divergent and non-divergent areas or between 2004 and 2005. The comparison of the 38 kHz ADCP and the 70 kHz Simrad echosounder data yielded a relationship of 4 ADCP counts for every 1 dB of Sv. This relationship was a promising start to a potential calibration for the ADCP instrument. Lastly, the analysis of localized sperm whale dive profiles identified three basic dive profiles; Deep (> 800 m), Mid-water dives to DSL depths (500 - 800 m) and Shallow (<500 m). The analysis also showed that whale dive behavior did not change based on time of day or location. It showed that whales are diving above the DSL as well as through and below, however these dives are independent of ... Book Sperm whale Texas A&M University Digital Repository |
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Open Polar |
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Texas A&M University Digital Repository |
op_collection_id |
fttexasamuniv |
language |
English |
topic |
Deep scattering layer Gulf of Mexico Sperm Whale |
spellingShingle |
Deep scattering layer Gulf of Mexico Sperm Whale Azzara, Alyson Julie Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior |
topic_facet |
Deep scattering layer Gulf of Mexico Sperm Whale |
description |
This research was carried out in support of fieldwork in the Gulf of Mexico in summers 2004 and 2005 as part of the multidisciplinary Sperm Whale Seismic Study (SWSS). Important aspects of SWSS research include oceanographic habitat characterization and studies of sperm whale foraging and diving patterns. During the SWSS 2005 cruise, acoustic volume backscatter data were collected using a 38 kHz ADCP for comparison with XBT, MODIS ocean color data, and whale dive profiles extrapolated from analysis of towed passive acoustic hydrophone array recordings of whale vocalizations. This unique data set, collected from a cyclonic eddy, was compared with non-upwelling conditions surveyed in the western Gulf and the Mississippi Canyon in summer 2004. My focus was to examine the relationship between acoustic backscatter intensity from the deep scattering layer (DSL; usually 400-600 m deep) and the depths to which whales dived. The results of the study investigate differences in DSL characteristics between divergent zones and non-divergent zones, and examine connections relating to variations in sperm whale dive patterns. The analysis of 38 kHz ADCP data showed that there were significant differences in some characteristics of the main DSL dependent on time of day. There were no significant differences in characteristics of the main DSL between divergent and non-divergent areas or between 2004 and 2005. The comparison of the 38 kHz ADCP and the 70 kHz Simrad echosounder data yielded a relationship of 4 ADCP counts for every 1 dB of Sv. This relationship was a promising start to a potential calibration for the ADCP instrument. Lastly, the analysis of localized sperm whale dive profiles identified three basic dive profiles; Deep (> 800 m), Mid-water dives to DSL depths (500 - 800 m) and Shallow (<500 m). The analysis also showed that whale dive behavior did not change based on time of day or location. It showed that whales are diving above the DSL as well as through and below, however these dives are independent of ... |
author2 |
Biggs, Douglas DiMarco, Steven Quigg, Antonietta Thode, Aaron |
format |
Book |
author |
Azzara, Alyson Julie |
author_facet |
Azzara, Alyson Julie |
author_sort |
Azzara, Alyson Julie |
title |
Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior |
title_short |
Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior |
title_full |
Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior |
title_fullStr |
Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior |
title_full_unstemmed |
Characteristics of the deep scattering layer in the Gulf of Mexico as they relate to sperm whale diving and foraging behavior |
title_sort |
characteristics of the deep scattering layer in the gulf of mexico as they relate to sperm whale diving and foraging behavior |
publishDate |
2009 |
url |
https://hdl.handle.net/1969.1/ETD-TAMU-1173 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_relation |
https://hdl.handle.net/1969.1/ETD-TAMU-1173 |
_version_ |
1771550428294545408 |