Marine animal sound classification

Software was developed to measure characteristics of marine animal sounds (AcouStat). These measurements proved effective for classifying sounds in several contexts: identifying species, quantifying the repertoire of a single species, and identifying individuals. The sound measures included statistics for aggregate bandwidth, intensity, duration, amplitude modulation, frequency modulation, center frequency, and interactions among these variables. Classification analysis based on these measures suggests they adequately characterize the variability of bioacoustic signals for many problems. Correct classification to species was as high as 85%, and correct classification of dolphin whistles to individual was 90%.Funding was provided by the Office of Naval Research through the Naval Undersea Warfare Center under Contract No. N-00140-90-D-1979

Characterizing acoustic features of marine animal sounds

Software tools were designed to characterize the acoustic features of marine animal sounds. These have resulted in a set of calculated measurements that summarize particular aspects of sound sequences. The specificity of these measurements was enhanced by adjusting calculations to compensate for ambient noise. The sound measures included statistics for Aggregate Bandwidth, Intensity, Duration, Amplitude Modulation, Frequency Modulation, Short-term Bandwidth, Center Frequency, and Amplitude Frequency Interaction. The efficacy of noise compensation was tested for each statistic. Then, the sound measures were tested on a subset of 200 sequences of marine animal sounds, including sequences from 20 species: six baleen whales, 13 toothed species, and one seal. The statistics were reviewed for each species and a graphical comparison of all species was generated using principal components analysis. Preliminary results confirm that such sounds can be classified by means of relatively simple statistical algorithms, and we are encouraged to continue toward a system for automatic classification of marine animal sounds.Funding was provided by NAVSEA under Contract No. N00140-90-D-1979 and a series of contracts and grants by ONR including Grant N00014-91-J-1445 with supplemental support by NOARL and ORINCON/DARPA

Software tools for acoustic database management

Digital archiving of bioacoustic data provides both curatorial and scientific benefits. To realize these benefits, key system requirements must be satisfied. This report discusses these requirements, and describes the software tools developed by the WHOI bioacoustic laboratory to maintain and utilize an archive of digitized biological sounds. These tools are written in standard C code, and are designed to run on PC-compatible microcomputers. Both the usage and structure of these programs are described in relation to the SOUND database of marine animal sounds. These tools include software for analog-to-digital conversion, text header maintenance, data verification and interactive spectrographic review. Source code listings are supplied.Funding was provided by the Office of Naval Research through the Ocean Acoustics Program (code 11250) Contract N00014-88-K-0273 and Grant N00014-J-1445 with supplemental support from NOARL (code 211)

SOUND database of marine animal vocalizations : structure and operations

The SOUND database system for marine animal vocalizations has been updated to include changes in the structure and operations that have evolved with use. These include more convenient operations, greater flexibilty in analysis routines, and a revised database structure. The formats for data sorting and indexing, database structure, and analysis routines have developed into a convenient research tool. This report is a revision of the earlier operating manual for the SOUND databases (Watkins, Fristrup, and Daher 1991.) The interactive databases that comprise the SOUND system provide comprehensive means for quantitative analyses and statistical comparisons of marine animal vocalizations. These SOUND databases encompass (1) descriptive text databases cataoging the WHOI collection of underwater sound recordings of marine animals, (2) sets of files of digital sound sequences, (3) text databases organizing the digital sound cuts, and (4) software for analysis, display, playback, and export of selected sound files. The text databases index and sort the information about the sounds, and the digital sound cut files are accessed directly from the text record. From the text database, the sound cut data may be analyzed on screen, listened to, and compared or exported as desired. The objective of this work has been the development of a basic set of tools for the study of marine animal sound. The text databases for cataloging the recordings provide convenient sorting and selection of sounds of interest. Then, as specific sequences are digitized from these recordings, they become part of another database system that manages these acoustic data. Once a digital sound is part of the organized database, several tools are available for interactive spectrographic display, sound playback, statistical feature extraction, and export to other application programs.Funding was provided by the Office of Naval Research through the Ocean Acoustics Program (code 11250A) under Contract No. N00014-88-K-0273 and No. N00014-91-J-1445 with supplemental support by ORINCON/DARPA and NRL (code 211)

Marine animal SOUND database

Cover and title page missing from original document.The Marine Animal SOUND Database system encompasses (1) descriptive text databases cataoging the WHOI collection of underwater sound recordings from marine animal, (2) sets of files of digital sound sequences, (3) text database organizing the digital sound sequences, and (4) software for analysis, display, playback, and export of selected sound files. The text databases index and sort the information on the sounds. The digital sound files are accessed directly from the text record, analyzed on screen, listened to, and compared or exported as desired. These databases provide comprehensive means for quantitative analyses and statistical comparisons of marine animal vocalizations. The objective has been to develop basic tools for the study of marine animal sounds. The text database for cataloging the collection of recordings provides convenient sorting and selection of sounds of interest. Then, as specific sequences are digitized from these recordigs, they become part of a second database system that manages these sound data. Once a digital sound is part of the database, several tools are available for interactive spectrogram display, sound playback, statistical feature extraction, and export to other application programs.Support for the development of the Marine Animal SOUND Databases has been from the Ocean Acoustics Program (code 11250A) of the Office of Naval Research, Contract NOOOI4-88-K-0273 and Research Grant NOOOI4-91-J-1445, with supplementary support through NOARL (code 211). The program of bioacoustic studies that provided much of the previous work resulting in our acoustic recordings of marine life was also supported for a considerable period by the Oceanic Biology Program of ONR

VOICE - a spectrogram computer display package

A real-time spetrogram instrument has been developed to provide an inexpensive and field-portable instrument for the analysis of animal sounds. The instrument integrates a computer graphics display package with a PC-AT computer equipped with an A/D board and a digital signal processing board. It provides a real-time spectrogram display of frequencies up to 50kHz in a variety of modes: a running display, a signal halted on screen, successive expanded views of the signal. The signal amplitude may also be displayed. Portions of the scrolled data may be saved to disk file for future viewing, or as part of a database collection. The screen display may be manipulated to adapt to special needs. Program source listings are included in the text.Funding was provided by the Office of Naval Research through Grant Nos. N00014-88-K-0273 and N00014-87-K-0236, the National Institutes of Health through Grant No.1 R29 NS25290, and the Andrew W. Mellon Foundation

Accuracy of an acoustic location system for monitoring the position of duetting songbirds in tropical forest

A field test was conducted on the accuracy of an eight-microphone acoustic location system designed to triangulate the position of duetting rufous-and-white wrens (Thryothorus rufalbus) in Costa Rica\u27s humid evergreen forest. Eight microphones were set up in the breeding territories of 20 pairs of wrens, with an average intermicrophone distance of 75.2±2.6 m. The array of microphones was used to record antiphonal duets broadcast through stereo loudspeakers. The positions of the loudspeakers were then estimated by evaluating the delay with which the eight microphones recorded the broadcast sounds. Position estimates were compared to coordinates surveyed with a global-positioning system (GPS). The acoustic location system estimated the position of loudspeakers with an error of 2.82±0.26 m and calculated the distance between the male and female loudspeakers with an error of 2.12±0.42 m. Given the large range of distances between duetting birds, this relatively low level of error demonstrates that the acoustic location system is a useful tool for studying avian duets. Location error was influenced partly by the difficulties inherent in collecting high accuracy GPS coordinates of microphone positions underneath a lush tropical canopy and partly by the complicating influence of irregular topography and thick vegetation on sound transmission. © 2006 Acoustical Society of America

Measuring acoustic habitats

Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies

Anthropogenic noise events perturb acoustic communication networks

Anthropogenic noise sources impact ecological processes by altering wildlife behavior and interactions with cascading impacts on community structure. The distribution and magnitude of such noise has grown exponentially over the past century, and now inundates even remote areas. Here we investigate biological responses to prolific, anthropogenic noise sources associated with the physical presence of the source (vehicle noise and human voices) and disconnected from it (aircraft overflight). Bioacoustic responses to these noise sources were documented at 103 sites in 40 U. S. National Park units. The presence of bird sounds was noted in 10-s audio samples every 2 min, for 8 days at each site and related to the presence of human voices, vehicle noise, and aircraft noise in the same and preceding samples. Generalized additive models were used to fit smoothing splines to weight the influence of noise in past samples on the probability of detecting bird sounds in the present sample. We found that the probability of hearing birds increased immediately following noise events, and decreased about 2 h after the event. The negative effects were persistent more than 3 h after a noise event. The persistence of these responses – especially for noise from jets that were many kilometers distant – raises questions about the functional significance and ecological consequences of this altered activity, particularly in light of the widespread and diverse habitats in this study and ubiquity of the noise sources evaluated