Definition of the Antarctic and Pygmy Blue Whale Call Templates. Application to Fast Automatic Detection (original) (raw)
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Detection range modeling of blue whale calls in Southwestern Indian Ocean
Applied Acoustics, 2010
In the Southwestern Indian Ocean, one year of continuous acoustic data from calibrated hydrophones maintained by the International Monitoring System provided data on blue whale calls from two subspecies Antarctic and pygmy blue whales. Using an automatic detection method with a fixed threshold, both call types were detected and received levels were measured for each detected call. By using a parabolic equation loss model configured with the precise characteristics of the biological source, hydroacoustic station, and environment in the study area, distances at which calls could be detected were estimated. These methods were used to define the maximum detection range around each array of hydrophones and the influence of the seasonal variation of the ambient noise and sound velocity on the detection ranges. Results showed that detection ranges were critically dependent on the choice of the biological source's input parameters, including frequency bandwidth and source level. Over the course of the year, detection distances were different for both subspecies; the pygmy blue whale seemed to be consistently closer to the station than the Antarctic blue whale. The distribution of the estimated distances confirmed the presence of both subspecies of blue whales near the Crozet Islands showing the importance of this sub-Antarctic area for these endangered species, especially during the austral summer feeding season.
2018
The International Whaling Commission (IWC) carried out blue whale research components within its annual austral summer Southern Ocean Whale and Ecosystem Research (SOWER) cruises between 1996 and 2010. Over 700 sonobuoys were deployed to record blue whale vocalizations during 11 Antarctic and three low latitude blue whale cruises off Australia, Madagascar and Chile. The recorded acoustic files from these deployments were collated and reviewed to develop a database of both the digital acoustic files and the associated deployment station metadata of 7,486 acoustic files from 484 stations. Acoustic files were analysed using the automated detection template and visual verification methods. We found a significant difference between the total number of acoustic recording hours (2,481) reported for these cruises (in the associated cruise reports) and the currently available number of acoustic recording hours (1,541). Antarctic blue whale vocalizations (9,315 and 24,902 Dand Z-calls) were d...
Scientific Reports
Since 2001, hundreds of thousands of hours of underwater acoustic recordings have been made throughout the Southern Ocean south of 60° S. Detailed analysis of the occurrence of marine mammal sounds in these circumpolar recordings could provide novel insights into their ecology, but manual inspection of the entirety of all recordings would be prohibitively time consuming and expensive. Automated signal processing methods have now developed to the point that they can be applied to these data in a cost-effective manner. However training and evaluating the efficacy of these automated signal processing methods still requires a representative annotated library of sounds to identify the true presence and absence of different sound types. This work presents such a library of annotated recordings for the purpose of training and evaluating automated detectors of Antarctic blue and fin whale calls. Creation of the library has focused on the annotation of a representative sample of recordings t...
2019
The International Whaling Commission (IWC) carried out blue whale research within its annual austral summer Southern Ocean Whale and Ecosystem Research (SOWER) cruises between 1996 and 2010. Over 700 sonobuoys were deployed to record blue whale vocalisations during 11 Antarctic and three low latitude blue whale cruises off Australia, Madagascar and Chile. The recorded acoustic files from these deployments were collated and reviewed to develop a database of both the digital acoustic files and the associated deployment station metadata of 7,486 acoustic files from 484 stations. Acoustic files were analysed using the automated detection template and visual verification method. We found a significant difference between the total number of acoustic recording hours (2,481) reported for these cruises (in the associated cruise reports) and the currently available number of acoustic recording hours (1,541). Antarctic blue whale vocalisations (9,315 D-calls and 24,902 Z-calls) were detected o...
2009
The problem of detection and recognition of contact calls produced by North Atlantic right whales, Eubalaena glacialis, is considered. A proposed solution is based on a multiple-stage hypothesis-testing technique involving a spectrogram-based detector, spectrogram testing, and feature vector testing algorithms. Results show that the proposed technique is able to detect over 80% of the contact calls detected by a human operator and to produce about 26 false alarms per 24 h of observation. s o m m a i r e Un problème de détection et reconnaissance des baleines noires, Eubaleana glacialis, en présence de bruit ambiant est étudié. Une solution proposée est basée sur une technique de test d 'hypothèses en plusieurs étapes, impliquant le détecteur, des tests de spectrogramme et des algorithmes testant des vecteurs de traits. Les résultats des tests montrent que la technique proposée est capable de détecter plus de 80% des appels de contact détectés par les opérateurs humains et de produire environ 26 fausses alarmes par 24 h d 'observation.
PLOS ONE, 2017
Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral summers of 1997 through 2009, south of 38˚S, coupled with visual observations of blue whales during the IWC SOWER line-transect surveys. The characteristic Z-call and D-call of Antarctic blue whales were detected using an automated detection template and visual verification method. Using a random forest model, we showed the environmental preferences pattern, spatial occurrence and acoustic behaviour of Antarctic blue whales. Distance to the southern boundary of the Antarctic Circumpolar Current (SBACC), latitude and distance from the nearest Antarctic shores were the main geographic predictors of blue whale call occurrence. Satellite-derived sea surface height, sea surface temperature, and productivity (chlorophyll-a) were the most important environmental predictors of blue whale call occurrence. Call rates of D-calls were strongly predicted by the location of the SBACC, latitude and visually detected number of whales in an area while call rates of Z-call were predicted by the SBACC, latitude and longitude. Satellite-derived sea surface height, wind stress, wind direction, water depth, sea surface temperatures, chlorophyll-a and wind speed were important environmental predictors of blue whale call rates in the Southern Ocean. Blue whale call occurrence and call rates varied significantly in response to inter-annual and long term variability of those environmental predictors. Our results identify the response of Antarctic blue whales to inter-annual variability in environmental conditions and highlighted potential suitable habitats for this population. Such emerging knowledge about the acoustic behaviour, environmental and habitat preferences of Antarctic blue whales is important in improving the management and conservation of this highly depleted species.
Seasonality of blue and fin whale calls west of the Antarctic Peninsula
Oceans 2003. Celebrating the Past ... Teaming Toward the Future (IEEE Cat. No.03CH37492), 2003
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Comparison of two methods for detection of North Atlantic Right Whale upcalls
2015 23rd European Signal Processing Conference (EUSIPCO), 2015
In this paper, a study is carried out for detecting North Atlantic Right Whale upcalls with measurements from passive acoustic monitoring devices. Preprocessed spectrograms of upcalls are subjected to two different tasks, one of which is based on extraction of time-frequency features from upcall contours, and the other that employs a Local Binary Pattern operator to extract salient texture features of the upcalls. Then several classifiers are used to evaluate the effectiveness of both the contour-based and texture-based features for upcall detection. Detection results reveal that popular classifiers such as Linear Discriminant Analysis, Support Vector Machine, and TreeBagger can achieve high detection rates. Furthermore, using LBP features for call detection shows improved accuracy of about 3% to 4% over time-frequency features when an identical classifier is used.
2015
We examined recordings from a 15-month (May 2009–July 2010) continuous acoustic data set collected from a bottom-mounted passive acoustic recorder at a sample frequency of 6kHz off Portland, Victoria, Australia (38°33′01″S, 141°15′13″E) off southern Australia. Analysis revealed that calls from both subspecies were recorded at this site, and general additive modeling revealed that the number of calls varied significantly across seasons. Antarctic blue whales were detected more frequently from July to October 2009 and June to July 2010, corresponding to the suspected breeding season, while Australian blue whales were recorded more frequently from March to June 2010, coinciding with the feeding season. In both subspecies, the number of calls varied with time of day; Antarctic blue whale calls were more prevalent in the night to early morning, while Australian blue whale calls were detected more often from midday to early evening. Using passive acoustic monitoring, we show that each subspecies adopts different seasonal and daily call patterns which may be related to the ecological strategies of these subspecies. This study demonstrates the importance of passive acoustics in enabling us to understand and monitor subtle differences in the behavior and ecology of cryptic sympatric marine mammals.
Out of the blue – acoustic monitoring of southern African blue whales
Growing to 30 m long and weighing up to 163 tonnes, Antarctic blue whales, Balaenoptera musculus intermedia, are the largest animal that ever lived on the planet; yet despite their enormous size, they feed on small Antarctic krill (Euphausia superba). Blue whales are not easily seen at sea as their numbers are severely reduced, however, they are great sound producers and their sounds can travel hundreds to thousands of metres from the vocalizing animal. We present here an experimental design and its contribution towards improving the knowledge of Antarctic blue whale abundance, distribution and seasonal patterns.