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Kathleen M. Stafford - One of the best experts on this subject based on the ideXlab platform.
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Distribution of Blue Whale populations in the Southern Indian Ocean based on a decade of acoustic monitoring
Deep Sea Research Part II: Topical Studies in Oceanography, 2020Co-Authors: Maëlle Torterotot, Flore Samaran, Kathleen M. Stafford, Jean-yves RoyerAbstract:Abstract Globally, the Indian Ocean appears to have the greatest Blue Whale (Balaenoptera musculus ssp) acoustic diversity, with at least four acoustic populations from three defined sub-species. To understand how these different populations use this region as habitat, we first need to characterize their spatial and seasonal distributions. Here, we build on previous passive acoustic monitoring studies and analyze a passive acoustic dataset spanning large temporal (9 years) and spatial (3–9 sites covering more than 12 million km2 of potential acoustic habitat in the southwest Indian Ocean) scales. A novel detection algorithm was employed to investigate the long-term presence of Antarctic Blue Whale and SEIO and SWIO pygmy Blue Whale calls. We found that Antarctic and pygmy Blue Whales have completely different spatial and seasonal distribution in the southern Indian Ocean. Antarctic Blue Whales are heard almost year-round on the whole array, with great inter-annual variability. The two pygmy Blue Whales share a highly stable seasonal acoustic presence, but their geographical distributions overlap at only a few central Indian Ocean sites. However, Antarctic and pygmy Blue Whale acoustic co-occurrence is common, especially in sub-tropical waters. These temporal and spatial distributions strengthen our understanding of seasonal occurrence and habitat use of distinct populations of Blue Whales in the southern Indian Ocean. A better comprehension of the ecology of Indian Ocean Blue Whales will require interdisciplinary studies to examine the drivers of the variability seen from passive acoustic studies.
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A Review of Blue Whale Studies from HARUphones in the Pacific
Modern Acoustics and Signal Processing, 2016Co-Authors: Kathleen M. StaffordAbstract:The earliest long-term monitoring of low-frequency signals of large Whales was via cabled military arrays. These arrays provided valuable new data but were restricted in the locations that were monitored and there was no open access to the data collected. In order to monitor the low-frequency signals of large Whales in different areas and over shorter time scales, Haruphones, single hydrophone, autonomous recording packages, were developed by the Pacific Marine Environmental Laboratory of the US National Oceanic and Atmospheric Administration and deployed in the Gulf of Alaska and the eastern tropical Pacific. By integrating the acoustic data from these broadly spaced deployments with other data streams, new discoveries about Blue Whales in the eastern Pacific Ocean were made. These included establishing the geographic range and migratory patterns of eastern north Pacific Blue Whales; establishing that the eastern tropical Pacific appears to be a Blue Whale “hot spot” where as many as four, but primarily three, acoustic populations of Blue Whales occur; determining that the Gulf of Alaska is a region where eastern and western North Pacific Blue Whales overlap in space and time; and showing that Blue Whale calling behavior has a diel pattern whereby animals produce more sounds at night than during the day. In aggregate, these data show that passive acoustic monitoring is a valuable tool for establishing Blue Whale population identity, determining habitat range, and studying behavioral ecology over long time periods and in remote regions of the ocean.
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estimating historical eastern north pacific Blue Whale catches using spatial calling patterns
PLOS ONE, 2014Co-Authors: Cole C Monnahan, Trevor A. Branch, Kathleen M. Stafford, Yulia V Ivashchenko, Erin M. OlesonAbstract:Blue Whales (Balaenoptera musculus) were exploited extensively around the world and remain endangered. In the North Pacific their population structure is unclear and current status unknown, with the exception of a well-studied eastern North Pacific (ENP) population. Despite existing abundance estimates for the ENP population, it is difficult to estimate pre-exploitation abundance levels and gauge their recovery because historical catches of the ENP population are difficult to separate from catches of other populations in the North Pacific. We collated previously unreported Soviet catches and combined these with known catches to form the most current estimates of North Pacific Blue Whale catches. We split these conflated catches using recorded acoustic calls from throughout the North Pacific, the knowledge that the ENP population produces a different call than Blue Whales in the western North Pacific (WNP). The catches were split by estimating spatiotemporal occurrence of Blue Whales with generalized additive models fitted to acoustic call patterns, which predict the probability a catch belonged to the ENP population based on the proportion of calls of each population recorded by latitude, longitude, and month. When applied to the conflated historical catches, which totaled 9,773, we estimate that ENP Blue Whale catches totaled 3,411 (95% range 2,593 to 4,114) from 1905–1971, and amounted to 35% (95% range 27% to 42%) of all catches in the North Pacific. Thus most catches in the North Pacific were for WNP Blue Whales, totaling 6,362 (95% range 5,659 to 7,180). The uncertainty in the acoustic data influence the results substantially more than uncertainty in catch locations and dates, but the results are fairly insensitive to the ecological assumptions made in the analysis. The results of this study provide information for future studies investigating the recovery of these populations and the impact of continuing and future sources of anthropogenic mortality.
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Seasonal and Geographic Variation of Southern Blue Whale Subspecies in the Indian Ocean
PloS one, 2013Co-Authors: Flore Samaran, Jean-yves Royer, Robert P. Dziak, Kathleen M. Stafford, Trevor A. Branch, Jason Gedamke, Christophe GuinetAbstract:Understanding the seasonal movements and distribution patterns of migratory species over ocean basin scales is vital for appropriate conservation and management measures. However, assessing populations over remote regions is challenging, particularly if they are rare. Blue Whales (Balaenoptera musculus spp) are an endangered species found in the Southern and Indian Oceans. Here two recognized subspecies of Blue Whales and, based on passive acoustic monitoring, four “acoustic populations” occur. Three of these are pygmy Blue Whale (B.m. brevicauda) populations while the fourth is the Antarctic Blue Whale (B.m. intermedia). Past whaling catches have dramatically reduced their numbers but recent acoustic recordings show that these oceans are still important habitat for Blue Whales. Presently little is known about the seasonal movements and degree of overlap of these four populations, particularly in the central Indian Ocean. We examined the geographic and seasonal occurrence of different Blue Whale acoustic populations using one year of passive acoustic recording from three sites located at different latitudes in the Indian Ocean. The vocalizations of the different Blue Whale subspecies and acoustic populations were recorded seasonally in different regions. For some call types and locations, there was spatial and temporal overlap, particularly between Antarctic and different pygmy Blue Whale acoustic populations. Except on the southernmost hydrophone, all three pygmy Blue Whale acoustic populations were found at different sites or during different seasons, which further suggests that these populations are generally geographically distinct. This unusual Blue Whale diversity in sub-Antarctic and sub-tropical waters indicates the importance of the area for Blue Whales in these former whaling grounds.
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Seasonal detection of three types of “pygmy” Blue Whale calls in the Indian Ocean
Marine Mammal Science, 2010Co-Authors: Kathleen M. Stafford, Emily Chapp, Delwayne R. Bohnenstiel, Maya TolstoyAbstract:The Indian Ocean is an area in which a rich suite of cetacean fauna, including at least two subspecies of Blue Whale, is found; yet little information beyond stranding data and short-term surveys for this species is available. Pygmy Blue Whale (Balaenoptera musculus spp.) call data are presented that provide novel information on the seasonal and geographic distribution of these animals. Acoustic data were recorded from January 2002 to December 2003 by hydrophones at three stations of the International Monitoring System, including two near the subequatorial Diego Garcia Atoll and a third southwest of Cape Leeuwin, Australia. Automated spectrogram correlation methods were used to scan for call types attributed to pygmy Blue Whales. Sri Lanka calls were the most common and were detected year-round off Diego Garcia. Madagascar calls were only recorded on the northern Diego Garcia hydrophone during May and July, whereas Australia calls were only recorded at Cape Leeuwin, between December and June. Differences in geographic and seasonal patterns of these three distinct call types suggest that they may represent separate acoustic populations of pygmy Blue Whales and that these “acoustic populations” should be considered when assessing conservation needs of Blue Whales in the Indian Ocean.
Ana Širović - One of the best experts on this subject based on the ideXlab platform.
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Blue Whale songs worldwide: an update
2017Co-Authors: Ana Širović, Mark A. Mcdonald, Naysa Balcazar-cabrera, Susannah J. Buchan, Salvatore Cerchio, Christopher W. Clark, Genevieve E Davis, K. P. Findlay, G Gagnon, N KyoAbstract:Blue Whales produce regionally-distinct songs. In over a decade since McDonald and colleagues published a summary of biogeographic differences in Blue Whale songs worldwide, multiple new publications have explored the seasonality and distribution of those songs. We review the spatial and temporal occurrence of previously-defined song types and report several new Blue Whale song types. At least thirteen songs believed to be produced by Blue Whales are now known worldwide, five more than reported in the previous review. In the North Pacific Ocean there are three Blue Whale songs: the well-studied Northeast Pacific song, the Central North Pacific (previously called Northwest and North Pacific) song, and a new song recorded off Hokkaido, Japan. There is spatial overlap of the Northeast Pacific and Central North Pacific songs in the Gulf of Alaska. Similarly, the new song co-occurs with the Central North Pacific song off Hokkaido. Only one Blue Whale song occurs in the North Atlantic. At least nine songs are present in the Southern Hemisphere. The Antarctic Blue Whale song is the most widely distributed, occurring in the Southern Ocean as well as seasonally extending into the other oceans of the Southern Hemisphere. The Indian Ocean has the largest variety of Blue Whale songs, with new data suggesting the Southwest Indian Ocean song should have type locality Madagascar, with Diego Garcia possibly another song-type. Southeast Pacific contains two distinct, co-occurring songs. We report a new song in the South Atlantic, near South Georgia Island, that also occurs seasonally off Ascension Island. Occasionally Blue Whale songs were recorded outside of their reported range, indicating individuals at times roam more broadly. However, this is not a common occurrence. This new information and finer details of occurrence will enable further development of hypotheses for Blue Whale population structure based on acoustics.
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Central and western Pacific Blue Whale song and occurrence
The Journal of the Acoustical Society of America, 2016Co-Authors: Pollyanna Fisher-pool, Erin M. Oleson, Ana ŠirovićAbstract:Blue Whale (Balenoptera musculus) occurrence in the central and western Pacific is not fully understood. However, passive acoustics offer an effective way to monitor remote sites. Blue Whale songs are regionally distinct, and their stereotyped characteristics may be used to distinguish populations. Most Blue Whale song consists of multiple, pulsed and tonal units. However, song in the central and western Pacific consists of only simple tonal units. We investigated song variability of Hawaii, Wake Atoll, Palmyra, and Tinian in the Mariana Islands Archipelago, and highlight differences between Blue Whale songs amongst sites. Song calls of two different frequencies were recorded by High-frequency Acoustic Recording Packages. Detailed measures of call frequency were taken along the contours of tonal calls and patterning of song sequences was evaluated for recordings from the four locations during 2012 and 2013. The spatial and temporal occurrence of these patterns is discussed.
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Variability in the performance of the spectrogram correlation detector for North-east Pacific Blue Whale calls
Bioacoustics, 2015Co-Authors: Ana ŠirovićAbstract:AbstractSpectrogram correlation has been used successfully for automatic detection of baleen Whale calls. However, applying this method consistently to long time series can be challenging. To illustrate the potential challenges of the automatic detection process, recordings collected in the Southern California Bight between 2007 and 2012 were used for detection of North-east Pacific Blue Whale (Balaenoptera musculus) B calls. The effects of the following factors were investigated: Blue Whale B call frequency shift and appropriate kernel modification, seasonal variability in call abundance, analyst variability and noise. Due to intra- and inter-annual changes in the call frequency of Blue Whale B calls, seasonal and annual adjustments to the call detection kernel were needed. To account for seasonal variability in call production, evaluation of the detector against ground truth data was performed at multiple times during the year. Analyst variability did not affect overall long-term trends in detection, bu...
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Using passive acoustics to model Blue Whale habitat off the Western Antarctic Peninsula
Deep-sea Research Part Ii-topical Studies in Oceanography, 2010Co-Authors: Ana Širović, John A. HildebrandAbstract:Abstract Habitat preferences of calling Blue Whales were investigated using data from two multidisciplinary oceanographic cruises conducted off the Western Antarctic Peninsula (WAP) during the austral falls of 2001 and 2002. Data were collected on depth, temperature, salinity, chlorophyll a (Chl-a) concentration, krill biomass, zooplankton abundance, and Blue Whale call presence. In 2001, the study area was sea ice free, high Chl-a concentrations occurred over a small area, krill biomass and zooplankton abundance were high, and few Blue Whale calls were detected. In 2002 the sea ice covered the southern part of the survey area, Chl-a was high over a large area, krill and zooplankton were low, and there were more Blue Whale calls. Logistic regression analysis revealed Blue Whale calls were positively correlated with depth and SST, and negatively correlated with the mean zooplankton abundance from 101 to 300 m and the mean krill biomass in the top 100 m. The negative correlation between Blue Whale calls and zooplankton could occur if feeding animals do not produce calls. Our survey area did not cover the full range of Blue Whale habitat off the WAP, as Blue Whales probably follow the melting and freezing ice edge through this region. Passive acoustics can provide insight to mesoscale habitat use by Blue Whales in the Southern Ocean where visual sightings are rare, but the ability to localize on the calling animals would greatly improve the ability to model at a finer scale.
John A. Hildebrand - One of the best experts on this subject based on the ideXlab platform.
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Using passive acoustics to model Blue Whale habitat off the Western Antarctic Peninsula
Deep-sea Research Part Ii-topical Studies in Oceanography, 2010Co-Authors: Ana Širović, John A. HildebrandAbstract:Abstract Habitat preferences of calling Blue Whales were investigated using data from two multidisciplinary oceanographic cruises conducted off the Western Antarctic Peninsula (WAP) during the austral falls of 2001 and 2002. Data were collected on depth, temperature, salinity, chlorophyll a (Chl-a) concentration, krill biomass, zooplankton abundance, and Blue Whale call presence. In 2001, the study area was sea ice free, high Chl-a concentrations occurred over a small area, krill biomass and zooplankton abundance were high, and few Blue Whale calls were detected. In 2002 the sea ice covered the southern part of the survey area, Chl-a was high over a large area, krill and zooplankton were low, and there were more Blue Whale calls. Logistic regression analysis revealed Blue Whale calls were positively correlated with depth and SST, and negatively correlated with the mean zooplankton abundance from 101 to 300 m and the mean krill biomass in the top 100 m. The negative correlation between Blue Whale calls and zooplankton could occur if feeding animals do not produce calls. Our survey area did not cover the full range of Blue Whale habitat off the WAP, as Blue Whales probably follow the melting and freezing ice edge through this region. Passive acoustics can provide insight to mesoscale habitat use by Blue Whales in the Southern Ocean where visual sightings are rare, but the ability to localize on the calling animals would greatly improve the ability to model at a finer scale.
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worldwide decline in tonal frequencies of Blue Whale songs
Endangered Species Research, 2009Co-Authors: Mark A. Mcdonald, John A. Hildebrand, Sarah L MesnickAbstract:Blue Whale Balaenoptera musculus songs can be divided into at least 10 types world- wide, each type retaining the same units and similar phrasing over decades, unlike humpback Whale song which changes substantially from year to year. Historical acoustic recordings dating back as far as the 1960s were examined, measuring the tonal frequencies of 1000s of Blue Whale songs. Within a given year, individuals match the song frequency (related to 'pitch' in musical nomenclature) to within less than 3%. The best documented song type, that observed offshore of California, USA, now is sung at a frequency 31% lower than it was in the 1960s. Data available for 7 of the world's 10 known song types show they are all shifting downward in frequency, though at different rates. Any behavioral, ecological, oceanographic or anthropogenic change hypothesis seeking to explain the observed shifts should account for the worldwide occurrence of a nearly linear downward shift in the tonal frequencies of Blue Whale song. Hypotheses examined consider sexual selection, increasing ocean noise, increasing Whale body size post whaling, global warming, interference from other ani- mal sounds and post whaling increases in abundance. None of the commonly suggested hypotheses were found to provide a full explanation; however, increasing population size post whaling provides an intriguing and testable hypothesis that recovery is altering the sexually selected tradeoff for singing males between song amplitude (the ability to be heard at a greater distance) and song frequency (the ability to produce songs of lower pitch).
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biogeographic characterization of Blue Whale song worldwide using song to identify populations
Journal of Cetacean Research and Management, 2006Co-Authors: Mark A. Mcdonald, Sarah L Mesnick, John A. HildebrandAbstract:Blue Whale songs provide a measure for characterising worldwide Blue Whale population structure. These songs are divided into nine regional types, which maintain a stable character. Five of the nine song types have been recorded over time spans greater than 30 years showing no significant change in character. The nine song types can be divided into those containing only simple tonal components (high latitude North Pacific, North Atlantic and Southern Ocean song types), those comprised of complex pulsed units in addition to the tonal components (Pacific Ocean margin song types from California, Chile and New Zealand), and those which have the greatest complexity of all and the longest cycling times (Indian Ocean song types from Sri Lanka, Fremantle and Diego Garcia). We suggest that temporally stable differences in song provide another characteristic for comparison with genetic and morphological data when defining Blue Whale populations. Furthermore, as Mellinger and Barlow (2003) recommend, when there is a lack of other data or lack of clarity in other data sets, evidence of distinct differences in songs between areas should be used as a provisional hypothesis about population structure when making management decisions. Worldwide study is needed to better understand the various populations and subspecies within species like the Blue Whale that have large geographic distributions and have both migrating and resident populations.
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Blue Whale balaenoptera musculus diel call patterns offshore of southern california
Aquatic Mammals, 2005Co-Authors: Sean M. Wiggins, Mark A. Mcdonald, Erin M. Oleson, John A. HildebrandAbstract:Diel and seasonal calling patterns for Blue Whales (Balaenoptera musculus) were observed in coastal waters off southern California using seafloormounted autonomous acoustic recording packages (ARPs). Automated call counting from spectrogram cross-correlation showed peak seasonal calling in late summer/early fall. When call counts were organized by daily time intervals, calling peaks were observed during twilight periods, just after sunset and before sunrise. Minimum calling was observed during the day. Nighttime calling was greater than daytime calling, but also showed a minimum between the dusk and dawn calling peaks. These peaks correlate with the vertical migration times of krill, the Blue Whales’ primary prey. One hypothesis to explain these diel variations is that Blue Whale calling and foraging may be mutually exclusive activities. Fewer calls are produced during the day while prey are aggregated at depth and foraging is efficient. More calls are produced during the twilight time periods when prey are vertically migrating and at night when prey are dispersed near the sea surface and foraging is less efficient.
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Multiyear study of Blue Whale calls in the north Pacific
The Journal of the Acoustical Society of America, 2001Co-Authors: John A. Hildebrand, Mark A. Mcdonald, Rex K. Andrew, James A. Mercer, Bruce M. HoweAbstract:Multiyear acoustic recordings provide new insight on Blue Whale behavior in the Northern Pacific. We analyze six years of Blue Whale acoustic recordings made in the North Pacific as part of the ATOC (Acoustic Thermometry of Ocean Climate) and NPAL (North Pacific Acoustic Laboratory) projects. Blue Whale calls are recorded as a component of ambient sound data, preserved as spectra with 500 Hz Nyquist frequency in 1 Hz bins, averaged over 170 s and recorded at 5 min intervals at each of 13 sites from 1994 to the present. These data verify a separation of Blue Whale calls into a Western Pacific version with two primary frequencies near 20 Hz and weak harmonic components, and an Eastern Pacific version with a primary near 17 Hz, a strong harmonic component near 50 Hz and a strong overtone near 90 Hz. The frequency of the Eastern Pacific Blue Whale call has shifted downward throughout the last 40 years, and the present data, combined with published sources, show the frequency shift to be secular and nearly lin...
Mark A. Mcdonald - One of the best experts on this subject based on the ideXlab platform.
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Blue Whale songs worldwide: an update
2017Co-Authors: Ana Širović, Mark A. Mcdonald, Naysa Balcazar-cabrera, Susannah J. Buchan, Salvatore Cerchio, Christopher W. Clark, Genevieve E Davis, K. P. Findlay, G Gagnon, N KyoAbstract:Blue Whales produce regionally-distinct songs. In over a decade since McDonald and colleagues published a summary of biogeographic differences in Blue Whale songs worldwide, multiple new publications have explored the seasonality and distribution of those songs. We review the spatial and temporal occurrence of previously-defined song types and report several new Blue Whale song types. At least thirteen songs believed to be produced by Blue Whales are now known worldwide, five more than reported in the previous review. In the North Pacific Ocean there are three Blue Whale songs: the well-studied Northeast Pacific song, the Central North Pacific (previously called Northwest and North Pacific) song, and a new song recorded off Hokkaido, Japan. There is spatial overlap of the Northeast Pacific and Central North Pacific songs in the Gulf of Alaska. Similarly, the new song co-occurs with the Central North Pacific song off Hokkaido. Only one Blue Whale song occurs in the North Atlantic. At least nine songs are present in the Southern Hemisphere. The Antarctic Blue Whale song is the most widely distributed, occurring in the Southern Ocean as well as seasonally extending into the other oceans of the Southern Hemisphere. The Indian Ocean has the largest variety of Blue Whale songs, with new data suggesting the Southwest Indian Ocean song should have type locality Madagascar, with Diego Garcia possibly another song-type. Southeast Pacific contains two distinct, co-occurring songs. We report a new song in the South Atlantic, near South Georgia Island, that also occurs seasonally off Ascension Island. Occasionally Blue Whale songs were recorded outside of their reported range, indicating individuals at times roam more broadly. However, this is not a common occurrence. This new information and finer details of occurrence will enable further development of hypotheses for Blue Whale population structure based on acoustics.
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Blue Whale vocalizations recorded around new zealand 1964 2013
Journal of the Acoustical Society of America, 2014Co-Authors: Brian S. Miller, Mark A. Mcdonald, Jay Barlow, Kym Collins, Susannah Calderan, Russell Leaper, Paul Ensor, Paula A. Olson, Carlos Olavarría, Michael C. DoubleAbstract:Previous underwater recordings made in New Zealand have identified a complex sequence of low frequency sounds that have been attributed to Blue Whales based on similarity to Blue Whale songs in other areas. Recordings of sounds with these characteristics were made opportunistically during the Southern Ocean Research Partnership's recent Antarctic Blue Whale Voyage. Detections of these sounds occurred all around the South Island of New Zealand during the voyage transits from Nelson, New Zealand to the Antarctic and return. By following acoustic bearings from directional sonobuoys, Blue Whales were visually detected and confirmed as the source of these sounds. These recordings, together with the historical recordings made northeast of New Zealand, indicate song types that persist over several decades and are indicative of the year-round presence of a population of Blue Whales that inhabits the waters around New Zealand. Measurements of the four-part vocalizations reveal that Blue Whale song in this region has changed slowly, but consistently over the past 50 years. The most intense units of these calls were detected as far south as 53°S, which represents a considerable range extension compared to the limited prior data on the spatial distribution of this population.
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Blue Whale vocalizations recorded around New Zealand: 1964–2013
The Journal of the Acoustical Society of America, 2014Co-Authors: Brian S. Miller, Mark A. Mcdonald, Jay Barlow, Kym Collins, Susannah Calderan, Russell Leaper, Paul Ensor, Paula A. Olson, Carlos Olavarría, Michael C. DoubleAbstract:Previous underwater recordings made in New Zealand have identified a complex sequence of low frequency sounds that have been attributed to Blue Whales based on similarity to Blue Whale songs in other areas. Recordings of sounds with these characteristics were made opportunistically during the Southern Ocean Research Partnership's recent Antarctic Blue Whale Voyage. Detections of these sounds occurred all around the South Island of New Zealand during the voyage transits from Nelson, New Zealand to the Antarctic and return. By following acoustic bearings from directional sonobuoys, Blue Whales were visually detected and confirmed as the source of these sounds. These recordings, together with the historical recordings made northeast of New Zealand, indicate song types that persist over several decades and are indicative of the year-round presence of a population of Blue Whales that inhabits the waters around New Zealand. Measurements of the four-part vocalizations reveal that Blue Whale song in this region has changed slowly, but consistently over the past 50 years. The most intense units of these calls were detected as far south as 53°S, which represents a considerable range extension compared to the limited prior data on the spatial distribution of this population.
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worldwide decline in tonal frequencies of Blue Whale songs
Endangered Species Research, 2009Co-Authors: Mark A. Mcdonald, John A. Hildebrand, Sarah L MesnickAbstract:Blue Whale Balaenoptera musculus songs can be divided into at least 10 types world- wide, each type retaining the same units and similar phrasing over decades, unlike humpback Whale song which changes substantially from year to year. Historical acoustic recordings dating back as far as the 1960s were examined, measuring the tonal frequencies of 1000s of Blue Whale songs. Within a given year, individuals match the song frequency (related to 'pitch' in musical nomenclature) to within less than 3%. The best documented song type, that observed offshore of California, USA, now is sung at a frequency 31% lower than it was in the 1960s. Data available for 7 of the world's 10 known song types show they are all shifting downward in frequency, though at different rates. Any behavioral, ecological, oceanographic or anthropogenic change hypothesis seeking to explain the observed shifts should account for the worldwide occurrence of a nearly linear downward shift in the tonal frequencies of Blue Whale song. Hypotheses examined consider sexual selection, increasing ocean noise, increasing Whale body size post whaling, global warming, interference from other ani- mal sounds and post whaling increases in abundance. None of the commonly suggested hypotheses were found to provide a full explanation; however, increasing population size post whaling provides an intriguing and testable hypothesis that recovery is altering the sexually selected tradeoff for singing males between song amplitude (the ability to be heard at a greater distance) and song frequency (the ability to produce songs of lower pitch).
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biogeographic characterization of Blue Whale song worldwide using song to identify populations
Journal of Cetacean Research and Management, 2006Co-Authors: Mark A. Mcdonald, Sarah L Mesnick, John A. HildebrandAbstract:Blue Whale songs provide a measure for characterising worldwide Blue Whale population structure. These songs are divided into nine regional types, which maintain a stable character. Five of the nine song types have been recorded over time spans greater than 30 years showing no significant change in character. The nine song types can be divided into those containing only simple tonal components (high latitude North Pacific, North Atlantic and Southern Ocean song types), those comprised of complex pulsed units in addition to the tonal components (Pacific Ocean margin song types from California, Chile and New Zealand), and those which have the greatest complexity of all and the longest cycling times (Indian Ocean song types from Sri Lanka, Fremantle and Diego Garcia). We suggest that temporally stable differences in song provide another characteristic for comparison with genetic and morphological data when defining Blue Whale populations. Furthermore, as Mellinger and Barlow (2003) recommend, when there is a lack of other data or lack of clarity in other data sets, evidence of distinct differences in songs between areas should be used as a provisional hypothesis about population structure when making management decisions. Worldwide study is needed to better understand the various populations and subspecies within species like the Blue Whale that have large geographic distributions and have both migrating and resident populations.
Bruce R. Mate - One of the best experts on this subject based on the ideXlab platform.
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defining priority areas for Blue Whale conservation and investigating overlap with vessel traffic in chilean patagonia using a fast fitting movement model
Scientific Reports, 2021Co-Authors: Luis Bedrinanaromano, Bruce R. Mate, Rodrigo Huckegaete, Francisco A Viddi, Devin S Johnson, Alexandre N Zerbini, Juan M Morales, Daniel M PalaciosAbstract:Defining priority areas and risk evaluation is of utmost relevance for endangered species` conservation. For the Blue Whale (Balaenoptera musculus), we aim to assess environmental habitat selection drivers, priority areas for conservation and overlap with vessel traffic off northern Chilean Patagonia (NCP). For this, we implemented a single-step continuous-time correlated-random-walk model which accommodates observational error and movement parameters variation in relation to oceanographic variables. Spatially explicit predictions of Whales’ behavioral responses were combined with density predictions from previous species distribution models (SDM) and vessel tracking data to estimate the relative probability of vessels encountering Whales and identifying areas where interaction is likely to occur. These estimations were conducted independently for the aquaculture, transport, artisanal fishery, and industrial fishery fleets operating in NCP. Blue Whale movement patterns strongly agreed with SDM results, reinforcing our knowledge regarding oceanographic habitat selection drivers. By combining movement and density modeling approaches we provide a stronger support for purported priority areas for Blue Whale conservation and how they overlap with the main vessel traffic corridor in the NCP. The aquaculture fleet was one order of magnitude larger than any other fleet, indicating it could play a decisive role in modulating potential negative vessel-Whale interactions within NCP.
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genoustics combining near field acoustic records genetic identity and photograph records of an individual Blue Whale off the central oregon coast
OCEANS Conference, 2019Co-Authors: Angela L Sremba, Robert P. Dziak, Joseph H. Haxel, Bruce R. Mate, Ana Sirovic, Daniel M Palacios, Scott C Baker, Craig E Hayslip, Debbie Steel, John CalambokidisAbstract:Here we present results of a pilot project to simultaneously collect photographs, acoustic call records, and tissue biopsy sample of a Blue Whale from the eastern North Pacific, with the goal to assign the individual to a population of origin based on acoustic call records and genetic profile. On 17 October 2018, a pair of Blue Whales was located ∼27 miles off the Oregon coast. Using a small research vessel, we documented the encounter with photographs and collected a tissue biopsy from one of the two Whales while their vocalizations were recorded using a drifting hydrophone. We constructed a DNA profile consisting of mitochondrial DNA haplotype, sex, and 15 microsatellite loci. The DNA profile identified the Blue Whale as male and the assignment test confirmed an eastern North Pacific origin through a comparison to reference databases of Blue Whales from the North Pacific, South Pacific, eastern tropical Pacific and Southern Ocean. A comparison of the photographs of the two Whales to a catalog of Blue Whale images from the eastern North Pacific showed both Whales had previously been sighted on more than one occasion in waters off California between 1994 and 2005. Review of the 68.7-minute drifting hydrophone record detected 5 “A” and 27 “B” type calls, which have been identified as typical eastern North Pacific call types. The maximum call received levels were ∼110 dB re $\mu\text{Pa}^{2}$ -Hz−1 estimated using the third harmonic of the B call which had a frequency range of ∼40-45 Hz and a high signal to noise ratio (∼40 dB). Based on a simple transmission loss estimate, the third harmonic received level suggests a ∼7 km distance from the hydrophone to the vocal Whale. GPS tracking showed the boat remained in an elliptical area (r∼10 km) while circling the pair of Whales, consistent with the sampled Whale as the call source. Although we cannot confirm the identity of the calling Whale, the photo-identification records confirm the two Blue Whales have previously been sighted in the eastern North Pacific and suggests our acoustic and genetic analysis results are consistent with previous studies showing the ability to link acoustic call types and the Whale's sex.
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A Pulsed-air Model of Blue Whale B Call Vocalizations
Scientific reports, 2017Co-Authors: Robert P. Dziak, Joseph H. Haxel, T. K. Lau, S. Heimlich, Jacqueline Caplan-auerbach, David K. Mellinger, H. Matsumoto, Bruce R. MateAbstract:Blue Whale sound production has been thought to occur by Helmholtz resonance via air flowing from the lungs into the upper respiratory spaces. This implies that the frequency of Blue Whale vocalizations might be directly proportional to the size of their sound-producing organs. Here we present a sound production mechanism where the fundamental and overtone frequencies of Blue Whale B calls can be well modeled using a series of short-duration (
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a pulsed air model of Blue Whale b call vocalizations
Scientific Reports, 2017Co-Authors: Robert P. Dziak, Joseph H. Haxel, T. K. Lau, S. Heimlich, David K. Mellinger, H. Matsumoto, Jacqueline Caplanauerbach, Bruce R. MateAbstract:Blue Whale sound production has been thought to occur by Helmholtz resonance via air flowing from the lungs into the upper respiratory spaces. This implies that the frequency of Blue Whale vocalizations might be directly proportional to the size of their sound-producing organs. Here we present a sound production mechanism where the fundamental and overtone frequencies of Blue Whale B calls can be well modeled using a series of short-duration (<1 s) wavelets. We propose that the likely source of these wavelets are pneumatic pulses caused by opening and closing of respiratory valves during air recirculation between the lungs and laryngeal sac. This vocal production model is similar to those proposed for humpback Whales, where valve open/closure and vocal fold oscillation is passively driven by airflow between the lungs and upper respiratory spaces, and implies call frequencies could be actively changed by the animal to center fundamental tones at different frequency bands during the call series.
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association between Blue Whale balaenoptera musculus mortality and ship strikes along the california coast
Aquatic Mammals, 2010Co-Authors: Michelle Bermankowalewski, Bruce R. Mate, Frances M D Gulland, Sarah Wilkin, John Calambokidis, Joe Cordaro, Dave Rotstein, Paul Collins, Krista Fahy, Samuel DoverAbstract:Blue Whales (Balaenoptera musculus) are distributed worldwide, and although severely depleted by commercial whaling, their abundance off the California coast now appears to be increasing. Little is known about natural causes of mortality of Blue Whales, but human-related mortality continues despite legal protection. Ship strikes are a significant mortality factor for other species of baleen Whale, and changes in shipping traffic have been advocated to minimize further deaths. Between 1988 and 2007, 21 Blue Whale deaths were reported along the California coast, typically one or two cases annually. Three pulses in strandings were observed, with three carcasses observed in fall 1988, three in 2002, and four in fall 2007. Two of the four animals in 2007 were first observed dead in the Santa Barbara Channel and had wounds typical of a ship strike. Blue Whale strandings were spatially associated with locations of shipping lanes, especially those associated with the Ports of Los Angeles and Long Beach, and were most common in the fall months.