scholarly journals Passive Acoustic Monitoring Reveals Spatio-Temporal Distributions of Antarctic and Pygmy Blue Whales Around Central New Zealand

2021 ◽  
Vol 7 ◽  
Author(s):  
Victoria E. Warren ◽  
Ana Širović ◽  
Craig McPherson ◽  
Kimberly T. Goetz ◽  
Craig A. Radford ◽  
...  
Keyword(s):  
New Zealand ◽  
Acoustic Monitoring ◽  
Critically Endangered ◽  
Blue Whale ◽  
Passive Acoustic Monitoring ◽  
Animal Populations ◽  
Spatio Temporal ◽  
Species Specific ◽  
Passive Acoustic ◽  
Blue Whales

Effective management of wild animal populations relies on an understanding of their spatio-temporal distributions. Passive acoustic monitoring (PAM) is a non-invasive method to investigate the distribution of free-ranging species that reliably produce sound. Critically endangered Antarctic blue whales (Balaenoptera musculus intermedia) (ABWs) co-occur with pygmy blue whales (B. m. brevicauda) (PBWs) around New Zealand. Nationally, both are listed as “data deficient” due to difficulties in access and visual sub-species identification. PAM was used to investigate the distributions of blue whales via sub-species specific song detections in central New Zealand. Propagation models, incorporating ambient noise data, enabled the comparison of detections among recording locations in different marine environments. ABW detections peaked during austral winter and spring, indicating that New Zealand, and the South Taranaki Bight (STB) in particular, is a migratory corridor for ABWs. Some ABW calls were also detected during the breeding season (September and October). PBW calls were highly concentrated in the STB, particularly between March and May, suggesting that an aggregation of PBWs may occur here. Therefore, the STB is of great importance for both sub-species of blue whale. PBW detections were absent from the STB during parts of austral spring, but PBWs were detected at east coast locations during this time. Detection area models were valuable when interpreting and comparing detections among recording locations. The results provide sub-species specific information required for management of critically endangered ABWs and highlight the relative importance of central New Zealand for both sub-species of blue whale.

scholarly journals Estimating the abundance of the critically endangered Baltic Proper harbour porpoise (Phocoena phocoena) population using passive acoustic monitoring

2021 ◽  
Author(s):  
Mats Amundin ◽  
Julia Carlström ◽  
Len Thomas ◽  
Ida Carlén ◽  
Jens Koblitz ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Acoustic Monitoring ◽  
Harbour Porpoise ◽  
Critically Endangered ◽  
Phocoena Phocoena ◽  
Passive Acoustic Monitoring ◽  
Animal Populations ◽  
Baltic Proper ◽  
The Baltic ◽  
Passive Acoustic

Knowing the abundance of a population is a crucial component to assess its conservation status and develop effective conservation plans. For most cetaceans, abundance estimation is difficult given their cryptic and mobile nature, especially when the population is small and has a transnational distribution. In the Baltic Sea, the number of harbour porpoises (Phocoena phocoena) has collapsed since the mid-20th century and the Baltic Proper harbour porpoise is listed as Critically Endangered by the IUCN; however, its abundance remains unknown. Here, one of the largest ever passive acoustic monitoring studies was carried out by eight Baltic Sea nations to estimate the abundance of the Baltic Proper harbour porpoise for the first time. By logging porpoise echolocation signals at 298 stations during May 2011-April 2013, calibrating the loggers’ spatial detection performance at sea, and measuring the click rate of tagged individuals, we estimated an abundance of 66-1,143 individuals (95% CI, point estimate 490) during May-October within the population’s proposed management border. The small abundance estimate strongly supports that the Baltic Proper harbour porpoise is facing an extremely high risk of extinction, and highlights the need for immediate and efficient conservation actions through international cooperation. It also provides a starting point in monitoring the trend of the population abundance to evaluate the effectiveness of management measures and determine its interactions with the larger neighbouring Belt Sea population. Further, we offer evidence that design-based passive acoustic monitoring can generate reliable estimates of the abundance of rare and cryptic animal populations across large spatial scales.

scholarly journals Bioacoustic characterization of mating calls of a freshwater fish (Prochilodus magdalenae) for passive acoustic monitoring

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Sebastián Muñoz-Duque ◽  
Silvia López-Casas ◽  
Héctor Rivera-Gutiérrez ◽  
Luz Jiménez-Segura
Keyword(s):  
Pulse Rate ◽  
Peak Frequency ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
Natural Habitats ◽  
Train Duration ◽  
Acoustic Characterization ◽  
Species Specific ◽  
Passive Acoustic

Fish produce sounds that are usually species-specific and associated with particular behaviors and contexts. Acoustic characterization enables the use of sounds as natural acoustic labels for species identification. Males of Prochilodus magdalenae produce mating sounds. We characterized  these sounds and tested their use in natural habitats, to use passive acoustic monitoring for spawning ground identification. We identified two types of acoustic signals: simple pulses and pulse trains. Simple pulses were 13.7 ms long, with peak frequency of 365 Hz, whereas pulse train were 2.3 s long, had peak frequency of 399 Hz, 48.6 pulses and its pulses lasted 12.2 ms, with interpulse interval of 49.0 ms long and 22.3 Hz pulse rate. We did not detect spawning in  absence of male calls nor differences in male sounds at different female densities. We found differences in train duration, pulse rate, and pulse duration in trains, according to the fish's source sites, but these sites were not well discriminated based on bioacoustical variables. In rivers, we located two P. magdalenae spawning grounds and recognized calls from another fish species (Megaleporinus muyscorum). We did not find a significant relationship between fish size and call peak frequency for P. magdalenae.

scholarly journals Passive Acoustic Monitoring of Gunshot Activity in Cooking Lake-Blackfoot Provincial Recreation Area

2019 ◽  
Vol 2 (2) ◽  
pp. 35-36
Author(s):  
Keelin Henderson-Pekarik ◽  
Richard Hedley ◽  
Justin Johnson ◽  
Jeremiah Kennedy ◽  
Erin Bayne
Keyword(s):  
Visual Representations ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
Hunting Behavior ◽  
Random Subset ◽  
Human Behaviors ◽  
The Past ◽  
Recreation Area ◽  
Spatio Temporal ◽  
Passive Acoustic

In the past, monitoring hunting behavior has been limited to self-reported numbers. However, the ability of autonomous recording units to monitor soundscapes may make them suitable for assessing spatio-temporal shooting patterns. Our goal for this project was to find out if it is possible to use acoustic monitoring to track human activity, and if there were differences in seasonal or daily shooting intensities. We hypothesized that shooting intensity would decrease from September to November and from the afternoon till morning due to people being less likely to go shooting in cooler temperatures. A grid of 91 ARU’s were deployed between September 2nd and November 30th, 2018 in Cooking Lake-Blackfoot Provincial Recreation Area. They were set to record continuously between sunrise and sunset with some recording during the night as well. We selected a random subset of 30 minute recordings, visualized them using spectrograms; visual representations of sound with time on the x-axis and frequency on the y-axis, and counted the gunshots in each. We compared differences in gunshot detections between months and different times of day using analysis of variance (ANOVA). There were no statistical differences found in seasonal or daily shooting intensities. One reason for this may be that sample sizes were low, due to the time needed to manually process recordings. We demonstrated that ARU’s can be used to provide us with an accurate way of assessing shooting patterns and therefore, be useful for monitoring other human behaviors such as detecting poachers, or assessing compliance with hunting laws.

scholarly journals Passive acoustic monitoring of the decline of Mexico's critically endangered vaquita

2016 ◽  
Vol 31 (1) ◽  
pp. 183-191 ◽  
Author(s):  
Armando Jaramillo-Legorreta ◽  
Gustavo Cardenas-Hinojosa ◽  
Edwyna Nieto-Garcia ◽  
Lorenzo Rojas-Bracho ◽  
Jay Ver Hoef ◽  
...  
Keyword(s):  
Acoustic Monitoring ◽  
Critically Endangered ◽  
Passive Acoustic Monitoring ◽  
Passive Acoustic

Sound production of the critically endangered totoaba (Totoaba macdonaldi): Laying the foundation for conservation of this species through passive acoustic monitoring

2019 ◽  
Vol 146 (4) ◽  
pp. 2855-2855
Author(s):  
Goldie Phillips ◽  
Gerald L. D'Spain ◽  
Catalina López-Sagástegui ◽  
Daniel Guevara ◽  
Miguel Angel Cisneros-Mata ◽  
...  
Keyword(s):  
Sound Production ◽  
Acoustic Monitoring ◽  
Critically Endangered ◽  
Passive Acoustic Monitoring ◽  
Totoaba Macdonaldi ◽  
Passive Acoustic

scholarly journals Automatic Detection and Compression for Passive Acoustic Monitoring of the African Forest Elephant

2019 ◽  
Vol 33 ◽  
pp. 476-484 ◽  
Author(s):  
Johan Bjorck ◽  
Brendan H. Rappazzo ◽  
Di Chen ◽  
Richard Bernstein ◽  
Peter H. Wrege ◽  
...  
Keyword(s):  
Acoustic Monitoring ◽  
Sub Saharan Africa ◽  
Conservation Strategies ◽  
Audio Signals ◽  
Passive Acoustic Monitoring ◽  
Network Bandwidth ◽  
African Forest Elephant ◽  
Animal Populations ◽  
Forest Elephant ◽  
Passive Acoustic

In this work, we consider applying machine learning to the analysis and compression of audio signals in the context of monitoring elephants in sub-Saharan Africa. Earth’s biodiversity is increasingly under threat by sources of anthropogenic change (e.g. resource extraction, land use change, and climate change) and surveying animal populations is critical for developing conservation strategies. However, manually monitoring tropical forests or deep oceans is intractable. For species that communicate acoustically, researchers have argued for placing audio recorders in the habitats as a costeffective and non-invasive method, a strategy known as passive acoustic monitoring (PAM). In collaboration with conservation efforts, we construct a large labeled dataset of passive acoustic recordings of the African Forest Elephant via crowdsourcing, compromising thousands of hours of recordings in the wild. Using state-of-the-art techniques in artificial intelligence we improve upon previously proposed methods for passive acoustic monitoring for classification and segmentation. In real-time detection of elephant calls, network bandwidth quickly becomes a bottleneck and efficient ways to compress the data are needed. Most audio compression schemes are aimed at human listeners and are unsuitable for low-frequency elephant calls. To remedy this, we provide a novel end-to-end differentiable method for compression of audio signals that can be adapted to acoustic monitoring of any species and dramatically improves over naive coding strategies.  

How high is high? Using percentile thresholds to identify peak bat activity

2015 ◽  
Vol 93 (4) ◽  
pp. 307-313 ◽  
Author(s):  
Amanda M. Adams ◽  
Liam P. McGuire ◽  
Lauren A. Hooton ◽  
M. Brock Fenton
Keyword(s):  
Specific Activity ◽  
Activity Patterns ◽  
Acoustic Monitoring ◽  
Activity Levels ◽  
Peak Activity ◽  
Passive Acoustic Monitoring ◽  
Data Set ◽  
Bat Activity ◽  
Species Specific ◽  
Passive Acoustic

Passive acoustic monitoring is a common tool used for monitoring bat activity levels. Identifying periods and locations of peak levels provides insight into bat ecology and has important management implications. One limitation of passive acoustic monitoring is the relative nature of the data, often relying on subjective interpretation of descriptive terminology such as “higher” or “lower”. We propose the use of percentile thresholds (PTs) for objectively identifying peak activity. By compiling a reference data set, it is possible to define percentiles of the observed activity levels and these percentiles can provide objective thresholds for comparing activity levels. We used acoustic recordings from sites in Canada and calculated PTs based on the distribution of the number of calls per hour across all nights and sites for three species of bat. Given species ecologies (e.g., hibernating, migrating), we were able to use PTs to objectively identify peak activity levels on a species-specific basis. Percentile thresholds are also a replicable method of describing within-night activity by evaluating species-specific activity patterns and important times of night. Our analyses and examples represent a proof of concept. The next step is to move towards a standardized distribution to generate PTs. Creating a public repository of acoustic data sets to evaluate activity of a species in the context of its entire range would allow us to standardize terms such as “high” activity in an objective manner.

scholarly journals Last call: Passive acoustic monitoring shows continued rapid decline of critically endangered vaquita

2017 ◽  
Vol 142 (5) ◽  
pp. EL512-EL517 ◽  
Author(s):  
Len Thomas ◽  
Armando Jaramillo-Legorreta ◽  
Gustavo Cardenas-Hinojosa ◽  
Edwyna Nieto-Garcia ◽  
Lorenzo Rojas-Bracho ◽  
...  
Keyword(s):  
Acoustic Monitoring ◽  
Critically Endangered ◽  
Rapid Decline ◽  
Passive Acoustic Monitoring ◽  
Passive Acoustic
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