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  • 1
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    An open access dataset for developing automated detectors of Antarctic baleen whale sounds and performance evaluation of two commonly used detectors (2021)
    In:  EPIC3Scientific Reports, 11(806)
    Details
    Publication Date: 2021-02-17
    Description: 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 to ensure that automated algorithms can be developed and tested across a broad range of instruments, locations, environmental conditions, and years. To demonstrate the utility of the library, we characterise the performance of two automated detection algorithms that have been commonly used to detect stereotyped calls of blue and fin whales. The availability of this library will facilitate development of improved detectors for the acoustic presence of Southern Ocean blue and fin whales. It can also be expanded upon to facilitate standardization of subsequent analysis of spatiotemporal trends in call-density of these circumpolar species.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 2
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    Towards collective circum-Antarctic passive acoustic monitoring: The Southern Ocean Hydrophone Network (SOHN) (2013)
    Alfred Wegener Institute for Polar and Marine Research & German Society of Polar Research
    In:  EPIC3Polarforschung, Bremerhaven, Alfred Wegener Institute for Polar and Marine Research & German Society of Polar Research, 83(2), pp. 47-61, ISSN: 00322490
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    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: "Polarforschung" , peerRev
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  • 3
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    Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types (2020)
    Nature Research
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Malige, F., Patris, J., Buchan, S. J., Stafford, K. M., Shabangu, F., Findlay, K., Hucke-Gaete, R., Neira, S., Clark, C. W., & Glotin, H. Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types. Scientific Reports, 10(1), (2020): 8121, doi:10.1038/s41598-020-64613-0.
    Description: A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The pulse rate of the song units as well as their peak frequency were measured using two different methods (summed auto-correlation and Fourier transform). The sources of error associated with each measurement were assessed. There was a linear decline in both parameters for the more common song type (southeast Pacific song type n.2) between 1997 to 2017. An abbreviated analysis, also showed a frequency decline in the scarcer southeast Pacific song type n.1 between 1970 to 2014, revealing that both song types are declining at similar rates. We discussed the use of measuring both pulse rate and peak frequency to examine the frequency decline. Finally, a comparison of the rates of frequency decline with other song types reported in the literature and a discussion on the reasons of the frequency shift are presented.
    Description: The authors thank the help of Explorasub diving center (Chile), Agrupación turística Chañaral de Aceituno (Chile), ONG Eutropia (Chile), Valparaiso university (Chile), the international institutions and research programs CTBTO, IWC, BRILAM STIC AmSud 17-STIC-01. S.J.B. thanks support from the Center for Oceanographic Research COPAS Sur-Austral, CONICYT PIA PFB31, Biology Department of Woods Hole Oceanographic Institution, the Office of Naval Research Global (awards N62909-16-2214 and N00014-17-2606), and a grant to the Centro de Estudios Avanzados en Zonas Ãridas (CEAZA) “Programa Regional CONICYT R16A10003”. We thank SABIOD MI CNRS, EADM MaDICS CNRS and ANR-18-CE40-0014 SMILES supporting this research. We are grateful to colleagues at DCLDE 2018 and SOLAMAC 2018 conferences for useful comments on the preliminary version of this work. In this work we used only the free and open-source softwares Latex, Audacity and OCTAVE.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 4
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    Listen to the BLUE: Towards a pan-Antarctic monitoring system and blueprint of analysis methods to study fin and Antarctic blue whales in the Southern Ocean (2013)
    In:  EPIC320th Biennal Conference on the Biology of Marine Mammals, Dunedin, New Zealand, 2013-12-09-2013-12-13
    Details
    Publication Date: 2022-09-29
    Description: The Southern Ocean Research Partnership (SORP) is an international collaborative initiative to develop novel research techniques and conduct non-lethal research on whales in the Southern Ocean. One of SORP’s original five research projects is the Blue and Fin Whale Acoustic Trends Project which aims to implement a long term acoustic research program examining trends in Southern Ocean blue and fin whale population growth, distribution, and seasonal presence using passive acoustic monitoring techniques. Passive acoustic monitoring is a robust means of monitoring whales in remote and difficult to study areas such as the Antarctic over long time periods. Analysis of a wide range of available passive acoustic data has demonstrated spatial and temporal patterns in the occurrence of blue and fin whales in the Southern Ocean. However, the lack of overlap in years and locations monitored, and differences among instrumentation and analysis methods used, underlines the need for coordinated effort. To best exploit passive acoustic methods for monitoring purposes in the future, the SORP Acoustic Trends steering group proposes the placement and maintenance of a pan-Antarctic monitoring system with consistent spatial and temporal coverage in each of the six IWC management areas. Further, blueprints for instrument choice, hardware configurations and analysis methods are being prepared to suggest how data might be best collected and analyzed in a uniform manner to best address the specific research questions for each study species. Through a consistent multi-disciplinary approach with international collaborators, the Blue and Fin Whale Acoustic Trends Project aims to use passive acoustic recordings to measure long term distribution, seasonal occurrence, and population growth trends of fin and Antarctic blue whales in the Southern Ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 5
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    Southern Ocean Research Partnership Blue and Fin Whale Acoustic Trends Working Group: current and future research challenges (2017)
    In:  EPIC3Society for Marine Mammalogy Biennial Conference - PAM workshop, Halifax, Canada, 2017-10
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    Publication Date: 2022-09-29
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 6
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    Blue whale songs worldwide: an update (2017)
    In:  EPIC322nd Biennial Conference on the Biology of Marine Mammals, Halifax, Canada, 2017-10
    Details
    Publication Date: 2022-09-29
    Description: 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.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 7
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    Interchange of Southern Hemisphere humpback whales across the South Atlantic Ocean. (2023)
    Details
    Publication Date: 2023-09-24
    Description: The cosmopolitan distribution of humpback whales (Megaptera novaeangliae) is largely driven by migrations between winter low-latitude breeding grounds and summer high-latitude feeding grounds. Southern Hemisphere humpback whales faced intensive exploitation during the whaling eras and recently show evidence of population recovery. Gene flow and shared song indicate overlap between the western (A) and eastern (B1, B2) Breeding Stocks in the South Atlantic and Indian Oceans (C1). Here, we investigated photo-identification evidence of population interchange using images of individuals photographed during boat-based tourism and research in Brazil and South Africa from 1989 to 2022. Fluke images were uploaded to Happywhale, a global digital database for marine mammal identification. Six whales were recaptured between countries from 2002 to 2021 with resighting intervals ranging from 0.76 to 12.92 years. Four whales originally photographed off Abrolhos Bank, Brazil were photographed off the Western Cape, South Africa (feeding grounds for B2). Two whales originally photographed off the Western Cape were photographed off Brazil, one traveling to the Eastern Cape in the Southwestern Indian Ocean (a migration corridor for C1) before migrating westward to Brazil. These findings photographically confirm interchange of humpback whales across the South Atlantic and Indian Oceans and the importance of international collaboration to understand population boundaries.
    Description: Challenge 4, 9
    Description: Published
    Description: Refereed
    Keywords: Humpback whales ; Migration ; Photo-identification
    Repository Name: AquaDocs
    Type: Journal Contribution
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  • 8
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    Combining Regional Habitat Selection Models for Large-Scale Prediction: Circumpolar Habitat Selection of Southern Ocean Humpback Whales. (2023)
    Details
    Publication Date: 2023-09-24
    Description: Machine learning algorithms are often used to model and predict animal habitat selection— the relationships between animal occurrences and habitat characteristics. For broadly distributed species, habitat selection often varies among populations and regions; thus, it would seem preferable to fit region- or population-specific models of habitat selection for more accurate inference and prediction, rather than fitting large-scale models using pooled data. However, where the aim is to make range-wide predictions, including areas for which there are no existing data or models of habitat selection, how can regional models best be combined? We propose that ensemble approaches commonly used to combine different algorithms for a single region can be reframed, treating regional habitat selection models as the candidate models. By doing so, we can incorporate regional variation when fitting predictive models of animal habitat selection across large ranges. We test this approach using satellite telemetry data from 168 humpback whales across five geographic regions in the Southern Ocean. Using random forests, we fitted a large-scale model relating humpback whale locations, versus background locations, to 10 environmental covariates, and made a circumpolar prediction of humpback whale habitat selection. We also fitted five regional models, the predictions of which we used as input features for four ensemble approaches: an unweighted ensemble, an ensemble weighted by environmental similarity in each cell, stacked generalization, and a hybrid approach wherein the environmental covariates and regional predictions were used as input features in a new model. We tested the predictive performance of these approaches on an independent validation dataset of humpback whale sightings and whaling catches. These multiregional ensemble approaches resulted in models with higher predictive performance than the circumpolar naive model. These approaches can be used to incorporate regional variation in animal habitat selection when fitting range-wide predictive models using machine learning algorithms. This can yield more accurate predictions across regions or populations of animals that may show variation in habitat selection.
    Description: Challenges 4, 9
    Description: Published
    Description: Refereed
    Keywords: Ensembles ; Habitat selection ; Machine learning ; Resource selection functions ; Telemetry ; Humpback whales ; Megaptera novaeangliae
    Repository Name: AquaDocs
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  • 9
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    The Role of Environmental Drivers in Humpback Whale Distribution, Movement and Behavior: A Review. (2023)
    Details
    Publication Date: 2023-09-24
    Description: Humpback whales, Megaptera novaeangliae, are a highly migratory species exposed to a wide range of environmental factors during their lifetime. The spatial and temporal characteristics of such factors play a significant role in determining suitable habitats for breeding, feeding and resting. The existing studies of the relationship between oceanic conditions and humpback whale ecology provide the basis for understanding impacts on this species. Here we have determined the most relevant environmental drivers identified in peer-reviewed literature published over the last four decades, and assessed the methods used to identify relationships. A total of 148 studies were extracted through an online literature search. These studies used a combined estimated 105,000 humpback whale observations over 1,216 accumulated study years investigating the relationship between humpback whales and environmental drivers in both Northern and Southern Hemispheres. Studies focusing on humpback whales in feeding areas found preferences for areas of upwelling, high chlorophyll-a concentration and frontal areas with changes in temperature, depth and currents, where prey can be found in high concentration. Preferred calving grounds were identified as shallow, warm and with slow water movement to aid the survival of calves. The few studies of migration routes have found preferences for shallow waters close to shorelines with moderate temperature and chlorophyll-a concentration. Extracting information and understanding the influence of key drivers of humpback whale behavioral modes are important for conservation, particularly in regard to expected changes of environmental conditions under climate change.
    Description: Challenge 4, 9
    Description: Published
    Description: Refereed
    Keywords: Climate change ; Distribution drivers ; Cetaceans
    Repository Name: AquaDocs
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  • 10
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    Oceanographic anomalies coinciding with humpback whale super‑group occurrences in the Southern Benguela. (2023)
    Details
    Publication Date: 2023-09-24
    Description: Seasonal feeding behaviour of humpback whales (Megaptera novaeangliae) has been observed in the coastal waters of the Southern Benguela where the species has been observed forming super-groups during the austral spring in recent years since 2011. Super-groups are unprecedented densely-packed aggregations of between 20 and 200 individuals in low-latitude waters and their occurrences indicate possible changes in feeding behaviour of the species. We accessed published data on super-groups occurrence in the study area in 2011, 2014 and 2015, and investigated oceanographic drivers that support prey availability in this region. We found that enhanced primary production is a necessary but not sufficient condition for super-groups to occur. Positive chlorophyll anomalies occurring one month prior to the super-group occurrences were identified, but only a concurrent significantly reduced water volume export from the region throughout October were conducive to the aggregations in the specific years. Hydrodynamic model results attributed the anomalous decreased volume export to the strength and orientation of the Goodhope Jet and associated eddy activity. The combination of random enhanced primary production typical of the region and emerging anomalous conditions of reduced water export in October since 2011 resulted in favourable food availability leading to the unique humpback whale aggregations. The novelty of this grouping behaviour is indicative of the lack of such oceanographic conditions in the past. Given the recency of the events, it is difficult to attribute this reduction in ocean transport to climatic regime shifts, and the origin should be likely investigated in the distant water mass interaction with the greater Agulhas system rather than in local intensifications of the upwelling conditions. A positive trend in the humpback whale population abundance points to the need to monitor the exposure of the species to the changing climate conditions.
    Description: Challenge 4, 9
    Description: Published
    Description: Refereed
    Keywords: Humpback whales ; Feeding behaviour
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: 13pp.
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