The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Sean M Wiggins - One of the best experts on this subject based on the ideXlab platform.

  • 2005. Performance of spectrogram cross-correlation in detecting right whale calls in long-term recordings from the bering sea
    2015
    Co-Authors: Lisa M Munger, Sue E Moore, David K Mellinger, Sean M Wiggins, John A. Hildebr
    Abstract:

    We investigated the performance of spectrogram cross-correlation for automatically detecting North Pacifi c right whale (Eubalaena japonica) calls in long-term acoustic recordings from the southeastern Bering Sea. Data were sampled by autonomous, bottom-mounted hydrophones deployed in the southeastern Bering Sea from October 2000 through August 2002. A human analyst detected right whale calls within the fi rst month (October 2000) of recorded data by visually examining spectrograms and by listening to recorded data; these manual detections were then compared to results of automated detection trials. Automated detection by spectrogram cross-correlation was implemented using a synthetic kernel based on the most common right whale call type. To optimize automated detection parameters, the analyst performed multiple trials on minutes-long and hour-long recordings and manually adjusted detection parameters between trials. A single set of optimized detection parameters was used to process a week-long recording from October 2000. The automated detector trials resulted in increasing proportions of false and missed detections with increasing data set duration, due to the higher proportion of acoustic noise and lower overall call rates in longer recordings. However, the automated detector missed only one calling “bout ” (2 or more calls within a 10-minute span) of the 18 bouts present in the week-long recording. Despite the high number of false detections and misse

  • north pacific right whales Eubalaena japonica recorded in the northeastern pacific ocean in 2013
    Marine Mammal Science, 2015
    Co-Authors: Ana Sirovic, Sean M Wiggins, Sarah Johnson, Lauren K Roche, Leah M Varga, John A Hildebrand
    Abstract:

    Notes MARINE MAMMAL SCIENCE, **(*): ***–*** (*** 2014) © 2014 The Authors. Marine Mammal Science published by Wiley Periodicals, Inc. on behalf of Society for Marine Mammalogy This is an open access article under the terms of the Creative Commons Attribution- NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. DOI: 10.1111/mms.12189 North Pacific right whales (Eubalaena japonica) recorded in the northeastern Pacific Ocean in 2013 A NA S IROVI C , 1 S ARAH C. J OHNSON , L AUREN K. R OCHE , L EAH M. V ARGA , S EAN M. W IGGINS and J OHN A. H ILDEBRAND , Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive MC 0205, La Jolla, California 92093-0205, U.S.A. The North Pacific right whale (Eubalaena japonica) is among the most critically endangered marine mammals in the world (Brownell et al. 2001). Its population was drastically reduced by 19th and 20th century whaling and its recovery was addition- ally slowed by illegal Soviet whaling that occurred during the 1960s (Clapham et al. 2004, Ivashchenko and Clapham 2012). With a severe decrease in the population also came a restriction in range, from extensive distribution across the North Pacific, to a constricted presence of two different populations, one in the Sea of Okhotsk and along the Western Pacific, and the other in the eastern Bering Sea (Scarff 1986, Clap- ham et al. 2004, Josephson et al. 2008). The abundance estimates for the eastern pop- ulation are around 30 animals (Wade et al. 2006, 2011b; Marques et al. 2011), while the western population is considered to be larger with current estimates of probably no more than 300 animals (Brownell et al. 2001). Most baleen whales undertake seasonal migrations, spending summers feeding in high latitude, productive areas and winters in warmer, lower latitude breeding grounds (Kellogg 1929). North Pacific right whales spend their summers in the Ber- ing Sea and, to a lesser extent, the Gulf of Alaska, the Aleutian archipelago, and off Kodiak (Scarff 1986, Brownell et al. 2001, Clapham et al. 2004, Mellinger et al. 2004, Shelden et al. 2005, Wade et al. 2011a). Most current research effort has been focused within the area in the Southeastern Bering Sea where North Pacific right whales have been sighted most frequently (Wade et al. 2006, Munger et al. 2008). Over the years, however, a small number of sightings of single right whales have been Corresponding author (e-mail: asirovic@ucsd.edu).

  • north pacific right whale up call source levels and propagation distance on the southeastern bering sea shelf
    Journal of the Acoustical Society of America, 2011
    Co-Authors: Lisa M Munger, Sean M Wiggins
    Abstract:

    Call source levels, transmission loss, and ambient noise levels were estimated for North Pacific right whale (Eubalaena japonica) up-calls recorded in the southeastern Bering Sea in autumn of 2000 and 2001. Distances to calling animals, needed to estimate source levels, were based on two independent techniques: (1) arrival-time differences on three or more hydrophones and (2) shallow-water dispersion of normal modes on a single receiver. Average root-mean-square (rms) call source levels estimated by the two techniques were 178 and 176 dB re 1 μPa at 1 m, respectively, over the up-call frequency band, which was determined per call and averaged 90 to 170 Hz. Peak-to-peak source levels were 14 to 22 dB greater than rms levels. Transmission loss was approximately 15*log10(range), intermediate between cylindrical and spherical spreading. Ambient ocean noise within the up-call band varied from 72 to 91 dB re 1 μPa2/Hz. Under average noise conditions, call spectrograms were detectable for whales at distances up ...

  • estimating north pacific right whale Eubalaena japonica density using passive acoustic cue counting
    Endangered Species Research, 2011
    Co-Authors: Tiago Reis Marques, Lisa M Munger, Len Thomas, Sean M Wiggins
    Abstract:

    We present a method for estimating animal density from fixed passive acoustic detec- tors, and illustrate it by estimating the density of North Pacific right whales Eubalaena japonica in the areas surrounding 3 hydrophones deployed in the southeastern Bering Sea in 2001 to 2002 and 2005 to 2006. Input data were the distances to detected right whale calls, estimated using a normal mode sound propagation model, and call production rate, estimated from encounters by survey vessels with right whale groups. Given the scarcity of information about this highly endangered species, we also extrapolate our results to provide a tentative estimate of the total population size in shelf waters of the eastern Bering Sea. This gives a point estimate of 25 animals (CV 29.1%; 95% confidence interval 13-47), which agrees well with what little is known for this species. We discuss the assumptions underlying the method. Obtaining more reliable values requires a larger sample of randomly located hydrophones, together with improved estimates of call rate.

  • north pacific right whale Eubalaena japonica seasonal and diel calling patterns from long term acoustic recordings in the southeastern bering sea 2000 2006
    Marine Mammal Science, 2008
    Co-Authors: Lisa M Munger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    We assessed North Pacific right whale (Eubalaena japonica) seasonal and daily calling patterns in the southeastern Bering Sea (SEBS) using long-term hydrophone recordings from October 2000 through January 2006. We detected right whale calls on the SEBS middle shelf (depth) as early as May, intermittently throughout summer and fall, and as late as December. Calls also were detected on one day in June 2005 on the SEBS slope (>1,000 m), but were not detected near Kodiak Island from April to August 2003. In months with calls, detections occurred on more days in July–October (≥6 d/mo), than from May to June or November to December (≤3 d/mo). Calls were clustered in time and were usually detected on 1–3 consecutive days with a median interval of 6.5 d for calls >1 d apart. Hourly calling rates were significantly higher at night than during the day. These data indicate that right whales occur in the SEBS later in the year than previously known, intermittently pass through the middle-shelf study region, and usually remain there no longer than a few days. Right whale habitat use in the SEBS may intensify in mid-summer through early fall based on higher monthly and daily call detection rates.

John A Hildebrand - One of the best experts on this subject based on the ideXlab platform.

  • north pacific right whales Eubalaena japonica recorded in the northeastern pacific ocean in 2013
    Marine Mammal Science, 2015
    Co-Authors: Ana Sirovic, Sean M Wiggins, Sarah Johnson, Lauren K Roche, Leah M Varga, John A Hildebrand
    Abstract:

    Notes MARINE MAMMAL SCIENCE, **(*): ***–*** (*** 2014) © 2014 The Authors. Marine Mammal Science published by Wiley Periodicals, Inc. on behalf of Society for Marine Mammalogy This is an open access article under the terms of the Creative Commons Attribution- NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. DOI: 10.1111/mms.12189 North Pacific right whales (Eubalaena japonica) recorded in the northeastern Pacific Ocean in 2013 A NA S IROVI C , 1 S ARAH C. J OHNSON , L AUREN K. R OCHE , L EAH M. V ARGA , S EAN M. W IGGINS and J OHN A. H ILDEBRAND , Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive MC 0205, La Jolla, California 92093-0205, U.S.A. The North Pacific right whale (Eubalaena japonica) is among the most critically endangered marine mammals in the world (Brownell et al. 2001). Its population was drastically reduced by 19th and 20th century whaling and its recovery was addition- ally slowed by illegal Soviet whaling that occurred during the 1960s (Clapham et al. 2004, Ivashchenko and Clapham 2012). With a severe decrease in the population also came a restriction in range, from extensive distribution across the North Pacific, to a constricted presence of two different populations, one in the Sea of Okhotsk and along the Western Pacific, and the other in the eastern Bering Sea (Scarff 1986, Clap- ham et al. 2004, Josephson et al. 2008). The abundance estimates for the eastern pop- ulation are around 30 animals (Wade et al. 2006, 2011b; Marques et al. 2011), while the western population is considered to be larger with current estimates of probably no more than 300 animals (Brownell et al. 2001). Most baleen whales undertake seasonal migrations, spending summers feeding in high latitude, productive areas and winters in warmer, lower latitude breeding grounds (Kellogg 1929). North Pacific right whales spend their summers in the Ber- ing Sea and, to a lesser extent, the Gulf of Alaska, the Aleutian archipelago, and off Kodiak (Scarff 1986, Brownell et al. 2001, Clapham et al. 2004, Mellinger et al. 2004, Shelden et al. 2005, Wade et al. 2011a). Most current research effort has been focused within the area in the Southeastern Bering Sea where North Pacific right whales have been sighted most frequently (Wade et al. 2006, Munger et al. 2008). Over the years, however, a small number of sightings of single right whales have been Corresponding author (e-mail: asirovic@ucsd.edu).

  • north pacific right whale Eubalaena japonica seasonal and diel calling patterns from long term acoustic recordings in the southeastern bering sea 2000 2006
    Marine Mammal Science, 2008
    Co-Authors: Lisa M Munger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    We assessed North Pacific right whale (Eubalaena japonica) seasonal and daily calling patterns in the southeastern Bering Sea (SEBS) using long-term hydrophone recordings from October 2000 through January 2006. We detected right whale calls on the SEBS middle shelf (depth) as early as May, intermittently throughout summer and fall, and as late as December. Calls also were detected on one day in June 2005 on the SEBS slope (>1,000 m), but were not detected near Kodiak Island from April to August 2003. In months with calls, detections occurred on more days in July–October (≥6 d/mo), than from May to June or November to December (≤3 d/mo). Calls were clustered in time and were usually detected on 1–3 consecutive days with a median interval of 6.5 d for calls >1 d apart. Hourly calling rates were significantly higher at night than during the day. These data indicate that right whales occur in the SEBS later in the year than previously known, intermittently pass through the middle-shelf study region, and usually remain there no longer than a few days. Right whale habitat use in the SEBS may intensify in mid-summer through early fall based on higher monthly and daily call detection rates.

  • Performance of spectrogram cross correlation in detecting right whale calls in long-term recordings from the Bering Sea,”
    2005
    Co-Authors: Lisa M Munger, David K Mellinger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    ABSTRACT We investigated the performance of spectrogram cross-correlation for automatically detecting North Pacifi c right whale (Eubalaena japonica) calls in long-term acoustic recordings from the southeastern Bering Sea. Data were sampled by autonomous, bottom-mounted hydrophones deployed in the southeastern Bering Sea from October 2000 through August 2002. A human analyst detected right whale calls within the fi rst month (October 2000) of recorded data by visually examining spectrograms and by listening to recorded data; these manual detections were then compared to results of automated detection trials. Automated detection by spectrogram cross-correlation was implemented using a synthetic kernel based on the most common right whale call type. To optimize automated detection parameters, the analyst performed multiple trials on minutes-long and hour-long recordings and manually adjusted detection parameters between trials. A single set of optimized detection parameters was used to process a week-long recording from October 2000. The automated detector trials resulted in increasing proportions of false and missed detections with increasing data set duration, due to the higher proportion of acoustic noise and lower overall call rates in longer recordings. However, the automated detector missed only one calling "bout" (2 or more calls within a 10-minute span) of the 18 bouts present in the week-long recording. Despite the high number of false detections and missed individual calls, spectrogram cross-correlation was useful to guide a human analyst to sections of data with potential right whale calling bouts. Upon reviewing automatic detection events, the analyst could quickly dismiss false detections and search recordings before and after correct detections to fi nd missed calls, thus improving the effi ciency of searching for a small number of calls in long-term (months-to years-long) recordings

Lisa M Munger - One of the best experts on this subject based on the ideXlab platform.

  • 2005. Performance of spectrogram cross-correlation in detecting right whale calls in long-term recordings from the bering sea
    2015
    Co-Authors: Lisa M Munger, Sue E Moore, David K Mellinger, Sean M Wiggins, John A. Hildebr
    Abstract:

    We investigated the performance of spectrogram cross-correlation for automatically detecting North Pacifi c right whale (Eubalaena japonica) calls in long-term acoustic recordings from the southeastern Bering Sea. Data were sampled by autonomous, bottom-mounted hydrophones deployed in the southeastern Bering Sea from October 2000 through August 2002. A human analyst detected right whale calls within the fi rst month (October 2000) of recorded data by visually examining spectrograms and by listening to recorded data; these manual detections were then compared to results of automated detection trials. Automated detection by spectrogram cross-correlation was implemented using a synthetic kernel based on the most common right whale call type. To optimize automated detection parameters, the analyst performed multiple trials on minutes-long and hour-long recordings and manually adjusted detection parameters between trials. A single set of optimized detection parameters was used to process a week-long recording from October 2000. The automated detector trials resulted in increasing proportions of false and missed detections with increasing data set duration, due to the higher proportion of acoustic noise and lower overall call rates in longer recordings. However, the automated detector missed only one calling “bout ” (2 or more calls within a 10-minute span) of the 18 bouts present in the week-long recording. Despite the high number of false detections and misse

  • north pacific right whale up call source levels and propagation distance on the southeastern bering sea shelf
    Journal of the Acoustical Society of America, 2011
    Co-Authors: Lisa M Munger, Sean M Wiggins
    Abstract:

    Call source levels, transmission loss, and ambient noise levels were estimated for North Pacific right whale (Eubalaena japonica) up-calls recorded in the southeastern Bering Sea in autumn of 2000 and 2001. Distances to calling animals, needed to estimate source levels, were based on two independent techniques: (1) arrival-time differences on three or more hydrophones and (2) shallow-water dispersion of normal modes on a single receiver. Average root-mean-square (rms) call source levels estimated by the two techniques were 178 and 176 dB re 1 μPa at 1 m, respectively, over the up-call frequency band, which was determined per call and averaged 90 to 170 Hz. Peak-to-peak source levels were 14 to 22 dB greater than rms levels. Transmission loss was approximately 15*log10(range), intermediate between cylindrical and spherical spreading. Ambient ocean noise within the up-call band varied from 72 to 91 dB re 1 μPa2/Hz. Under average noise conditions, call spectrograms were detectable for whales at distances up ...

  • estimating north pacific right whale Eubalaena japonica density using passive acoustic cue counting
    Endangered Species Research, 2011
    Co-Authors: Tiago Reis Marques, Lisa M Munger, Len Thomas, Sean M Wiggins
    Abstract:

    We present a method for estimating animal density from fixed passive acoustic detec- tors, and illustrate it by estimating the density of North Pacific right whales Eubalaena japonica in the areas surrounding 3 hydrophones deployed in the southeastern Bering Sea in 2001 to 2002 and 2005 to 2006. Input data were the distances to detected right whale calls, estimated using a normal mode sound propagation model, and call production rate, estimated from encounters by survey vessels with right whale groups. Given the scarcity of information about this highly endangered species, we also extrapolate our results to provide a tentative estimate of the total population size in shelf waters of the eastern Bering Sea. This gives a point estimate of 25 animals (CV 29.1%; 95% confidence interval 13-47), which agrees well with what little is known for this species. We discuss the assumptions underlying the method. Obtaining more reliable values requires a larger sample of randomly located hydrophones, together with improved estimates of call rate.

  • north pacific right whale Eubalaena japonica seasonal and diel calling patterns from long term acoustic recordings in the southeastern bering sea 2000 2006
    Marine Mammal Science, 2008
    Co-Authors: Lisa M Munger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    We assessed North Pacific right whale (Eubalaena japonica) seasonal and daily calling patterns in the southeastern Bering Sea (SEBS) using long-term hydrophone recordings from October 2000 through January 2006. We detected right whale calls on the SEBS middle shelf (depth) as early as May, intermittently throughout summer and fall, and as late as December. Calls also were detected on one day in June 2005 on the SEBS slope (>1,000 m), but were not detected near Kodiak Island from April to August 2003. In months with calls, detections occurred on more days in July–October (≥6 d/mo), than from May to June or November to December (≤3 d/mo). Calls were clustered in time and were usually detected on 1–3 consecutive days with a median interval of 6.5 d for calls >1 d apart. Hourly calling rates were significantly higher at night than during the day. These data indicate that right whales occur in the SEBS later in the year than previously known, intermittently pass through the middle-shelf study region, and usually remain there no longer than a few days. Right whale habitat use in the SEBS may intensify in mid-summer through early fall based on higher monthly and daily call detection rates.

  • Performance of spectrogram cross correlation in detecting right whale calls in long-term recordings from the Bering Sea,”
    2005
    Co-Authors: Lisa M Munger, David K Mellinger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    ABSTRACT We investigated the performance of spectrogram cross-correlation for automatically detecting North Pacifi c right whale (Eubalaena japonica) calls in long-term acoustic recordings from the southeastern Bering Sea. Data were sampled by autonomous, bottom-mounted hydrophones deployed in the southeastern Bering Sea from October 2000 through August 2002. A human analyst detected right whale calls within the fi rst month (October 2000) of recorded data by visually examining spectrograms and by listening to recorded data; these manual detections were then compared to results of automated detection trials. Automated detection by spectrogram cross-correlation was implemented using a synthetic kernel based on the most common right whale call type. To optimize automated detection parameters, the analyst performed multiple trials on minutes-long and hour-long recordings and manually adjusted detection parameters between trials. A single set of optimized detection parameters was used to process a week-long recording from October 2000. The automated detector trials resulted in increasing proportions of false and missed detections with increasing data set duration, due to the higher proportion of acoustic noise and lower overall call rates in longer recordings. However, the automated detector missed only one calling "bout" (2 or more calls within a 10-minute span) of the 18 bouts present in the week-long recording. Despite the high number of false detections and missed individual calls, spectrogram cross-correlation was useful to guide a human analyst to sections of data with potential right whale calling bouts. Upon reviewing automatic detection events, the analyst could quickly dismiss false detections and search recordings before and after correct detections to fi nd missed calls, thus improving the effi ciency of searching for a small number of calls in long-term (months-to years-long) recordings

Sue E Moore - One of the best experts on this subject based on the ideXlab platform.

  • 2005. Performance of spectrogram cross-correlation in detecting right whale calls in long-term recordings from the bering sea
    2015
    Co-Authors: Lisa M Munger, Sue E Moore, David K Mellinger, Sean M Wiggins, John A. Hildebr
    Abstract:

    We investigated the performance of spectrogram cross-correlation for automatically detecting North Pacifi c right whale (Eubalaena japonica) calls in long-term acoustic recordings from the southeastern Bering Sea. Data were sampled by autonomous, bottom-mounted hydrophones deployed in the southeastern Bering Sea from October 2000 through August 2002. A human analyst detected right whale calls within the fi rst month (October 2000) of recorded data by visually examining spectrograms and by listening to recorded data; these manual detections were then compared to results of automated detection trials. Automated detection by spectrogram cross-correlation was implemented using a synthetic kernel based on the most common right whale call type. To optimize automated detection parameters, the analyst performed multiple trials on minutes-long and hour-long recordings and manually adjusted detection parameters between trials. A single set of optimized detection parameters was used to process a week-long recording from October 2000. The automated detector trials resulted in increasing proportions of false and missed detections with increasing data set duration, due to the higher proportion of acoustic noise and lower overall call rates in longer recordings. However, the automated detector missed only one calling “bout ” (2 or more calls within a 10-minute span) of the 18 bouts present in the week-long recording. Despite the high number of false detections and misse

  • north pacific right whale Eubalaena japonica seasonal and diel calling patterns from long term acoustic recordings in the southeastern bering sea 2000 2006
    Marine Mammal Science, 2008
    Co-Authors: Lisa M Munger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    We assessed North Pacific right whale (Eubalaena japonica) seasonal and daily calling patterns in the southeastern Bering Sea (SEBS) using long-term hydrophone recordings from October 2000 through January 2006. We detected right whale calls on the SEBS middle shelf (depth) as early as May, intermittently throughout summer and fall, and as late as December. Calls also were detected on one day in June 2005 on the SEBS slope (>1,000 m), but were not detected near Kodiak Island from April to August 2003. In months with calls, detections occurred on more days in July–October (≥6 d/mo), than from May to June or November to December (≤3 d/mo). Calls were clustered in time and were usually detected on 1–3 consecutive days with a median interval of 6.5 d for calls >1 d apart. Hourly calling rates were significantly higher at night than during the day. These data indicate that right whales occur in the SEBS later in the year than previously known, intermittently pass through the middle-shelf study region, and usually remain there no longer than a few days. Right whale habitat use in the SEBS may intensify in mid-summer through early fall based on higher monthly and daily call detection rates.

  • seasonal variability and detection range modeling of baleen whale calls in the gulf of alaska 1999 2002
    Journal of the Acoustical Society of America, 2007
    Co-Authors: Kathleen M Stafford, Sue E Moore, David K Mellinger, Christopher G Fox
    Abstract:

    Five species of large whales, including the blue (Balaenoptera musculus), fin (B. physalus), sei (B. borealis), humpback (Megaptera novaeangliae), and North Pacific right (Eubalaena japonica), were the target of commercial harvests in the Gulf of Alaska (GoA) during the 19th through mid-20th Centuries. Since this time, there have been a few summer time visual surveys for these species, but no overview of year-round use of these waters by endangered whales primarily because standard visual survey data are difficult and costly. From October 1999–May 2002, moored hydrophones were deployed in six locations in the GoA to record whale calls. Reception of calls from fin, humpback, and blue whales and an unknown source, called Watkins’ whale, showed seasonal and geographic variation. Calls were detected more often during the winter than during the summer, suggesting that animals inhabit the GoA year-round. To estimate the distance at which species-diagnostic calls could be heard, parabolic equation propagation lo...

  • historic and current habitat use by north pacific right whales Eubalaena japonica in the bering sea and gulf of alaska
    Mammal Review, 2005
    Co-Authors: Kim E W Shelden, Sue E Moore, Janice M Waite, Paul R Wade, David J Rugh
    Abstract:

    To help define areas and ecological parameters critical to the survival and recovery of the remnant population of North Pacific right whales, habitat use was investigated by examining all available sighting and catch records in the south-eastern Bering Sea (SEBS) and Gulf of Alaska (GOA) over the past two centuries. 2. Based on re-analyses of commercial whaling records, search effort, and resultant catches and sightings, waters of the: (i) SEBS slope and shelf, (ii) eastern Aleutian Islands and (iii) GOA slope and abyssal plain were important habitat for North Pacific right whales through the late 1960s. 3. Since 1980, the only area where right whales have been seen consistently is on the SEBS middle shelf. However, acoustic detections and single sightings have been reported in all other regions except the SEBS slope and oceanic GOA (areas where little, if any, acoustic and visual effort has occurred). 4. Sightings since 1979 were in waters 2000 m deep, indicating that their distribution is not restricted to shallow continental shelves. 5. North Pacific right whale sightings through the centuries have been associated with a variety of oceanic features, and there is little in common in the bathymetry of these regions. These whales appear to have a greater pelagic distribution than that observed in the North Atlantic, which may be related to the availability of larger copepods across the SEBS and GOA.

  • Performance of spectrogram cross correlation in detecting right whale calls in long-term recordings from the Bering Sea,”
    2005
    Co-Authors: Lisa M Munger, David K Mellinger, Sue E Moore, Sean M Wiggins, John A Hildebrand
    Abstract:

    ABSTRACT We investigated the performance of spectrogram cross-correlation for automatically detecting North Pacifi c right whale (Eubalaena japonica) calls in long-term acoustic recordings from the southeastern Bering Sea. Data were sampled by autonomous, bottom-mounted hydrophones deployed in the southeastern Bering Sea from October 2000 through August 2002. A human analyst detected right whale calls within the fi rst month (October 2000) of recorded data by visually examining spectrograms and by listening to recorded data; these manual detections were then compared to results of automated detection trials. Automated detection by spectrogram cross-correlation was implemented using a synthetic kernel based on the most common right whale call type. To optimize automated detection parameters, the analyst performed multiple trials on minutes-long and hour-long recordings and manually adjusted detection parameters between trials. A single set of optimized detection parameters was used to process a week-long recording from October 2000. The automated detector trials resulted in increasing proportions of false and missed detections with increasing data set duration, due to the higher proportion of acoustic noise and lower overall call rates in longer recordings. However, the automated detector missed only one calling "bout" (2 or more calls within a 10-minute span) of the 18 bouts present in the week-long recording. Despite the high number of false detections and missed individual calls, spectrogram cross-correlation was useful to guide a human analyst to sections of data with potential right whale calling bouts. Upon reviewing automatic detection events, the analyst could quickly dismiss false detections and search recordings before and after correct detections to fi nd missed calls, thus improving the effi ciency of searching for a small number of calls in long-term (months-to years-long) recordings

Fabien Leprieur - One of the best experts on this subject based on the ideXlab platform.

  • Global vulnerability of marine mammals to global warming
    Scientific Reports, 2020
    Co-Authors: Camille Albouy, Thomas L Frolicher, Valentine Delattre, Giulia Donati, Severine Albouy-boyer, Marta Rufino, Loïc Pellissier, David Mouillot, Fabien Leprieur
    Abstract:

    Although extinctions due to climate change are still uncommon, they might surpass those caused by habitat loss or overexploitation over the next few decades. Among marine megafauna, mammals fulfill key and irreplaceable ecological roles in the ocean, and the collapse of their populations may therefore have irreversible consequences for ecosystem functioning and services. Using a trait-based approach, we assessed the vulnerability of all marine mammals to global warming under high and low greenhouse gas emission scenarios for the middle and the end of the 21^st century. We showed that the North Pacific Ocean, the Greenland Sea and the Barents Sea host the species that are most vulnerable to global warming. Future conservation plans should therefore focus on these regions, where there are long histories of overexploitation and there are high levels of current threats to marine mammals. Among the most vulnerable marine mammals were several threatened species, such as the North Pacific right whale ( Eubalaena japonica ) and the dugong ( Dugong dugon ), that displayed unique combinations of functional traits. Beyond species loss, we showed that the potential extinctions of the marine mammals that were most vulnerable to global warming might induce a disproportionate loss of functional diversity, which may have profound impacts on the future functioning of marine ecosystems worldwide.