Download or read book Tracking and Monitoring Fin Whales Offshore the Galicia Margin Using Passive Acoustic Methods written by Jessica Fisher and published by . This book was released on 2017 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Singing Fin Whales Tracked Acoustically Offshore of Southern California written by Leah McLean Varga and published by . This book was released on 2016 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fin whales (Balaenoptera physalus) produce a stereotyped low frequency call (15-30 Hz) that can be detected at great range and is considered song when produced in a repeated pattern. These calls, referred to as 20 Hz calls, were localized and animals were tracked using a kilometer-scale array of four passive acoustic recorders deployed at approximately 800m depth, northwest of San Clemente Island in the Southern California Bight. A total of 4969 calls were localized over four continuous weeks during late fall of 2007. The average estimated source level for the localized calls was 190.9 ± 7.4 dB peak-to-peak re 1[mu]Pa2 at 1m. The majority of the calls in these data were in the form of a doublet song pattern, with average inter-pulse intervals (IPI) 13s and 18s. The tracks were the first to be recorded for singing fin whales transiting alone using passive acoustic monitoring. Acoustic tracking of fin whales provides insight into the ecology and behavior of the species. Estimating call source levels help future predictions of how these whales are impacted by anthropogenic noise. Call source level, along with calling behavior, provide important parameters required for population density estimation. Furthermore, studying fin whale song patterns may aid in distinguishing different subpopulations.

Download or read book Passive Acoustic Monitoring of North Atlantic Fin Whales with the Use of Ocean Bottom Seismic Arrays written by Laura Gilling and published by . This book was released on 2016 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Passive Acoustic Monitoring of Cetaceans written by Walter M. X. Zimmer and published by Cambridge University Press. This book was released on 2011-04-21 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Passive acoustic monitoring is increasingly used by the scientific community to study, survey and census marine mammals, especially cetaceans, many of which are easier to hear than to see. PAM is also used to support efforts to mitigate potential negative effects of human activities such as ship traffic, military and civilian sonar and offshore exploration. Walter Zimmer provides an integrated approach to PAM, combining physical principles, discussion of technical tools and application-oriented concepts of operations. Additionally, relevant information and tools necessary to assess existing and future PAM systems are presented, with Matlab code used to generate figures and results so readers can reproduce data and modify code to analyse the impact of changes. This allows the principles to be studied whilst discovering potential difficulties and side effects. Aimed at graduate students and researchers, the book provides all information and tools necessary to gain a comprehensive understanding of this interdisciplinary subject.

Download or read book Noisy Oceans written by Gaye Bayrakci and published by John Wiley & Sons. This book was released on 2023-12-19 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noisy Oceans Measuring devices such as ocean bottom seismometers and hydrophones designed to detect earthquakes pick up many other signals. These were previously ignored as background noise from unknown sources, but advanced technology now allows insights into the noise created from icebergs, ships, hydrothermal vents, whales, rain, marine engineering, and more. Noisy Oceans: Monitoring Seismic and Acoustic Signals in the Marine Environment is a comprehensive guide to non-tectonic marine noise originating from different environmental, biological, and anthropogenic sources. Volume highlights include: Overview of marine soundscapes and their sources Existing and new methods for studying acoustic signals Case studies from around the world Spans disciplines from geology and geophysicists to biology Explores the impacts and implications of marine noise The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Download or read book Characteristics of Fin Whale Vocalizations Recorded on Instruments in the Northeast Pacific Ocean written by Maria Michelle Josephine Weirathmueller and published by . This book was released on 2016 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on fin whale vocalizations recorded on ocean bottom seismometers (OBSs) in the Northeast Pacific Ocean, using data collected between 2003 and 2013. OBSs are a valuable, and largely untapped resource for the passive acoustic monitoring of large baleen whales. This dissertation is divided into three parts, each of which uses the recordings of fin whale vocalizations to better understand their calling behaviors and distributions. The first study describes the development of a technique to extract source levels of fin whale vocalizations from OBS recordings. Source levels were estimated using data collected on a network of eight OBSs in the Northeast Pacific Ocean. The acoustic pressure levels measured at the instruments were adjusted for the propagation path between the calling whales and the instruments using the call location and estimating losses along the acoustic travel path. A total of 1241 calls were used to estimate an average source level of 189 +/-5.8 dB re 1uPa @ 1m. This variability is largely attributed to uncertainties in the horizontal and vertical position of the fin whale at the time of each call, and the effect of these uncertainties on subsequent calculations. The second study describes a semi-automated method for obtaining horizontal ranges to vocalizing fin whales using the timing and relative amplitude of multipath arrivals. A matched filter is used to detect fin whale calls and pick the relative times and amplitudes of multipath arrivals. Ray-based propagation models are used to predict multipath times and amplitudes as function of range. Because the direct and first multiple arrivals are not always observed, three hypotheses for the paths of the observed arrivals are considered; the solution is the hypothesis and range that optimizes the fit to the data. Ray-theoretical amplitudes are not accurate and solutions are improved by determining amplitudes from the observations using a bootstrap method. Data from ocean bottom seismometers at two locations are used to assess the method: one on the Juan de Fuca Ridge, a bathymetrically complex mid-ocean ridge environment, and the other at a flat sedimented location in the Cascadia Basin. At both sites, the method is reliable up to ~4 km range which is sufficient to enable estimates of call density. The third study explores spatial and temporal trends in fin whale calling patterns. The frequency and inter-pulse interval of fin whale 20 Hz vocalizations were observed over 10 years from 2003-2013 on bottom mounted hydrophones and OBSs in the northeast Pacific Ocean. The instrument locations extended from 40°N and 130°W to 125°W with water depths ranging from 1500-4000 m. The inter-pulse interval (IPI) of fin whale song sequences was observed to increase at a rate of 0.59 seconds/year over the decade of observation. During the same time period, peak frequency decreased at a rate of 0.16 Hz/year. Two primary call patterns were observed. During the earlier years, the more commonly observed pattern had a single frequency and single IPI. In later years, a doublet pattern emerged, with two dominant frequencies and two IPIs. Many call sequences in the intervening years appeared to represent a transitional state between the two patterns. The overall trend was consistent across the entire geographical span, although some regional differences exist.

Download or read book Passive Acoustic Methods for Tracking Marine Mammals Using Widely Spaced Bottom Mounted Hydrophones written by and published by . This book was released on 2009 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term goal of this project is to improve passive acoustic methods for tracking marine mammals, with the primary effort dedicated to methods that use bottom-mounted hydrophones. When possible, tracking results are used to study marine mammal behavior and bioacoustics. The specific objective of the project is to develop and implement methods to deal with two specific challenges associated with tracking marine mammals using widely-spaced bottom-mounted hydrophone arrays: (1) multiple animals whose calls cannot be easily separated or associated, and (2) insufficient receiver coverage, in which case standard time-of-arrival (TOA) tracking methods fail. The project uses existing datasets to develop and apply the tracking methods. The main effort is directed toward data collected at Navy Ranges. The main species of interest are sperm whales, beaked whales, minke whales, and humpback whales. Most methods will be generalizable to other species. Although the two main tracking challenges addressed by this project (insufficient receiver coverage and multiple animals) are not exclusive of one another, initial efforts focus on isolating the problems and solving them separately. As the separate challenges are met, efforts will progress to the joint problem. Model-based tracking methods are used since they can account for depth-dependent sound speed profiles (particularly important as refraction becomes significant at long distances, such as on Navy ranges) and since they can accurately model and make use of multi-path arrivals. Methods are implemented using a Bayesian framework to incorporate available a priori information, get error estimates on position, and improve performance in uncertain and fluctuating environments. In this framework, a three-dimensional grid is created and the likelihood of an animal present is calculated for each grid point and time.

Download or read book The Development of Automated Detection Techniques for Passive Acoustic Monitoring as a Tool for Studying Beaked Whale Distribution and Habitat Preferences in the California Current Ecosystem written by and published by . This book was released on 2012 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, passive acoustic survey methods have become increasingly important in marine mammal population and ecosystem studies. Passive acoustic monitoring has been progressively combined with traditional visual survey techniques during line transect surveys for marine mammals. The objectives of this research were to test available automated detection methods for passive acoustic monitoring and integrate the best available method into standard marine mammal monitoring protocols for ship based surveys. Specifically, there were three overarching goals: 1) develop, test, and compare algorithms for automated classification of beaked whale signals; 2) employ and test techniques for beaked whale detection at sea; and, 3) use information from automated beaked whale detections to create the first acoustic based habitat models for beaked whale species and compare these with visual-based models for the same region. The goal of the first chapter was to evaluate the performance and utility of PAMGUARD 1.0 Core software for use in automated detection of marine mammal acoustic signals during towed array surveys. Three different detector configurations of PAMGUARD were compared. These automated detection algorithms were evaluated by comparing them to the results of manual detections made by an experienced bio-acoustician (author TMY). This study provides the first detailed comparisons of PAMGUARD automated detection algorithms to manual detection methods. The results of these comparisons clearly illustrate the utility of automated detection methods for odontocete species. Results of this work showed that the majority of whistles and click events can be reliably detected using PAMGUARD software. The second chapter moves beyond automated detection to examine and test automated classification algorithms for beaked whale species. Beaked whales are notoriously elusive and difficult to study, especially using visual survey methods. However, due to recent advances in passive acoustic monitoring techniques, beaked whales are now more effectively detected acoustically than visually during vessel-based (e.g. line-transect) surveys. Beaked whales signals can be discriminated from those of other cetaceans by the unique characteristics of their echolocation clicks (e.g. duration>175 [lower case mu]s, center frequencies between 30-40 kHz, inter-click intervals between 0.2-0.4 sec and frequency upsweeps). Furthermore, these same characteristics make these signals ideal candidates for testing automated detection and classification algorithms. There are several different beaked whale automated detectors currently available for use. However, no comparative analysis of detectors exists. Therefore, comparison between studies and datasets is difficult. The purpose the second chapter was to test, validate, and compare algorithms for detection of beaked whales in acoustic line-transect survey data. Six different detection algorithms (XBAT, Ishmael, PAMGUARD, ERMA, GMM and FMCD) were evaluated and compared. Detection trials were run on three sample days of towed-hydrophone array recordings collected by NOAA Southwest Fisheries Science Center (SWFSC) during which were confirmed visual sightings of beaked whales (Ziphius cavirostris and Mesoplodon peruvianus). Detections also were compared to human verified acoustic detections for a subset of these data. In order to measure the probabilities of false detection, each detector was also run on three sample recordings containing clicks from another species: Risso's dolphin (Grampus griseus). Qualitative and quantitative comparisons and the detection performance of the different algorithms are discussed. Using data collected at sea from the PAMGUARD classifier developed in Chapter 2 it was possible to measure the clicks from visually verified Baird's beaked whale encounters and use this data to develop classifiers that could discriminate Baird's beaked whales from other beaked whale species in future work. Echolocation clicks from Baird's beaked whales, Berardius bairdii, were recorded during combined visual and acoustic shipboard surveys of cetacean populations in the California Current Ecosystem (CCE) and with autonomous, long-term recorders at four different sites in the Southern California Bight (SCB). The preliminary measurement of the visually validated Baird's beaked whale echolocation signals recorded from the ship-based towed array were used as a basis for identifying Baird's signals in the seafloor-mounted autonomous recorder data. Echolocation signals were segregated into four subsets based on a Gaussian Mixture Model with five mixtures over the peak frequency distribution to describe variability in the signal measurements. The median peak frequency for each of the four subsets measured from towed array and [long-term seafloor data] was at approximately 9 kHz [9 kHz], 19 kHz [16 kHz], 24 kHz [25 kHz], and 35 kHz [43 kHz]. Two distinct signal types were found, one being a beaked whale-like frequency modulated (FM) pulse, the other being a dolphin-like broadband click. Median center frequency ranged over all subsets and both recording situations from 17 to 36 kHz, -10 dB bandwidth from 6 to 13 kHz, and Teager-energy duration from 260 to 570 [lower case mu]s. The median inter-pulse interval was 0.23 seconds. The description of Baird's echolocation signals provided here will allow for studies of their distribution and abundance using towed array data without associated visual sightings and from autonomous seafloor hydrophones. The passive acoustic detection algorithms for beaked whales developed using data from Chapters 2 and 3 were field tested during a three year period to test the reliability of acoustic beaked whale monitoring techniques and to use these methods to describe beaked whale habitat in the SCB. In 2009 and 2010, PAM methods using towed hydrophone arrays were tested. These methods proved highly effective for real-time detection of beaked whales in the SCB and were subsequently implemented in 2011 to successfully detect and track beaked whales during the ongoing Southern California Behavioral Response Study (SOCAL-BRS). The three year field effort has resulted in (1) the successful classification and tracking of Cuvier's (Ziphius cavirostris), Baird's (Berardius bairdii) and unidentified Mesoplodon beaked whale species and (2) the identification of areas of previously unknown beaked whale habitat use. Thus, providing a better understanding of the relationship between beaked whale occurrence and preferred habitat on a relatively small spatial scale. These findings will provide information for more effective management and conservation of beaked whales. The final step in this research was to utilize the passive acoustic detection techniques developed herin to predictively model beaked whale habitat use and preferences in the CCE. To date beaked whale habitat models have been limited in utility due primarily to the small samples of visual observations available to inform the models. This chapter uses a multifaceted approach to model beaked whale encounter rates in the CCE. Beaked whale acoustic encounters are utilized to inform Generalized Additive Models (GAMs) of encounter rate for beaked whales in the CCE and compare these to visual based models. Acoustic and visual based models were independently developed for a small beaked whale group and Baird's beaked whales. Species distributions were modeled using a combination of fixed spatial features (depth, slope, aspect, and distance to the 2000m isobaths) and variable oceanographic variables (i.e., SST, SSS, logC, and MLD). Two models were evaluated for visual and acoustic encounters, one that also included Beaufort sea state as a predictor variable in addition to those listed and one that did not include Beaufort sea state. The visual and acoustic models differed markedly for both small beaked whales and Baird's beaked whale in the predictor variables retained in the best fit models and the regions of high encounter rate prediction. The visual models that included Beaufort sea state as a predictor variable retained this variable in the best fit resulting models. Acoustic models for the small beaked whales retained fixed spatial features of depth, slope, aspect and distance to the 2000 m isobaths as predictors in the best fit model, whereas only mixed layer depth was retained as a predictor in the best fit Baird's beaked whale acoustic model. The visual best fit model retained aspect and SST as predictor variables for small beaked whales and retained all predictor variables in the best fit Baird's beaked whale model. Differences in all models for Baird's beaked whale compared to the small beaked whales indicate that Baird's beaked whale habitat preferences may be distinctive from other beaked whale species. This work promotes current understanding of beaked whale distribution and habitat that can be used to inform beaked whale management and conservation efforts. This study has demonstrated the feasibility of using acoustic data to inform habitat models. Future work will benefit from utilizing acoustic data to inform habitat models for beaked whales and likely for other cryptic species as well. The culmination of this research has advanced techniques used in passive acoustic monitoring during towed array marine mammal surveys. The ability to efficiently detect and classify beaked whales using a towed hydrophone array represents a significant contribution to the field of marine mammal science. This work promotes current understanding of beaked whale distribution and habitat preferences and the highlights the role of behavioral and physiological processes in habitat selection.

Download or read book Fin Whale Distribution in the Indian and Equatorial Pacific Oceans in Support of Passive Acoustic Density Estimation written by Julia Vernon and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of passive acoustic monitoring in population density estimation of marine mammals is a developing capability, providing an efficient and cost-effective alternative to visual surveys. However, this method of density estimation introduces new challenges. Passive acoustic density estimation incorporates several variables, including the number of animal vocalizations detected over a period of time, the probability of detecting vocalizations in a given area, and the vocalization rate of the species of interest. Automatic detectors are needed to quickly and effectively detect vocalizing animals in a large data set. Such detectors need to be assessed for effectiveness, accounting for inefficiencies and quantifying the probability of detecting a vocalization by the species of interest. Another challenge that arises is uncertainty in the geographic distribution of individuals. Estimating distribution through consideration of the horizontal azimuths of vocalizing animals reduces bias introduced by the assumption that on average, animals are uniformly distributed around the sensors.Low-frequency ambient noise data (

Download or read book Site Specific Passive Acoustic Detection and Densities of Humpback Whale Calls Off the Coast of California written by Tyler Adam Helble and published by . This book was released on 2013 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Passive acoustic monitoring of marine mammal calls is an increasingly important method for assessing population numbers, distribution, and behavior. Automated methods are needed to aid in the analyses of the recorded data. When a mammal vocalizes in the marine environment, the received signal is a filtered version of the original waveform emitted by the marine mammal. The waveform is reduced in amplitude and distorted due to propagation effects that are influenced by the bathymetry and environment. It is important to account for these effects to determine a site-specific probability of detection for marine mammal calls in a given study area. A knowledge of that probability function over a range of environmental and ocean noise conditions allows vocalization statistics from recordings of single, fixed, omnidirectional sensors to be compared across sensors and at the same sensor over time with less bias and uncertainty in the results than direct comparison of the raw statistics. This dissertation focuses on both the development of new tools needed to automatically detect humpback whale vocalizations from single-fixed omnidirectional sensors as well as the determination of the site-specific probability of detection for monitoring sites off the coast of California. Using these tools, detected humpback calls are "calibrated" for environmental properties using the site-specific probability of detection values, and presented as call densities (calls per square kilometer per time). A two-year monitoring effort using these calibrated call densities reveals important biological and ecological information on migrating humpback whales off the coast of California. Call density trends are compared between the monitoring sites and at the same monitoring site over time. Call densities also are compared to several natural and human-influenced variables including season, time of day, lunar illumination, and ocean noise. The results reveal substantial differences in call densities between the two sites which were not noticeable using uncorrected (raw) call counts. Additionally, a Lombard effect was observed for humpback whale vocalizations in response to increasing ocean noise. The results presented in this thesis develop techniques to accurately measure marine mammal abundances from passive acoustic sensors.

Download or read book Advancement of Methods for Passive Acoustic Monitoring a Framework for the Study of Deep diving Cetacean written by Alba Solsona Berga and published by . This book was released on 2019 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine mammals face numerous anthropogenic threats, including fisheries interactions, ocean noise, ship strikes, and marine debris. Monitoring the negative impact on marine mammals through the assessment of population trends requires information about population size, spatiotemporal distribution, population structure, and animal behavior. Passive acoustic monitoring has become a viable method for gathering long-term data on highly mobile and notoriously cryptic marine mammals. However, passive acoustic monitoring still faces major challenges requiring further development of robust analysis tools, especially as it becomes increasingly used in applied conservation for long-term and large-scale studies of endangered or data deficient species such as sperm or beaked whales. Further challenges lie in the translation of animal presence into quantitative population density estimates since methods must control for variation in acoustic detectability of the target species, environmental factors, and for species-specific vocalization rates. The main contribution of this thesis is the advancement of the framework for long-term quantitative monitoring of cetacean species, applied to deep-divers like sperm and beaked whales. Fully-automated methods were developed and implemented to different populations of beaked whales in different conditions. This provided insight into generalization capabilities of these automatic techniques and best practices. However, implementing these tool kits is not always practical, and alternative methods for additional data processing were developed to expeditiously serve multiple purposes including annotation of individual sounds, evaluation of data in order to provide a highly dynamic technique, and classification for quantitative monitoring studies. This work also presents the longest time series of sperm whale presence using passive acoustic monitoring for over seven years in the Gulf of Mexico. Echolocation clicks were detected and discriminated from other sounds to understand the spatiotemporal distribution and structure of the population. A series of steps were implemented to provide adequate parameters and characteristics of the target population for density estimation using an echolocation click-based method. This allowed for the study of the Gulf of Mexico's sperm whale population, providing significant progress towards the understanding of the population structure, distribution, and trends, in addition to potential long-term impacts of the well-known catastrophic Deepwater Horizon oil spill and other anthropogenic activities. The emergence of innovative approaches for detecting the presence of marine mammals and documenting human interactions can provide insight into ecosystem change. These species can be used as sentinels of ocean health to ensure the conservation of their marine environment into the next epoch.

Download or read book Fin Whale Continuous Frequentation of St Lawrence Habitats Detected from Multi year Passive Acoustic Monitoring PAM written by Nathalie Roy and published by . This book was released on 2019 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Passive Acoustic Tracking of Minke Whales written by and published by . This book was released on 2011 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project developed model-based 3D passive acoustic tracking methods for minke whales. It was conducted in support of ONR Award N000140910489 in which T. Norris (Bio-Waves) conducted visual surveys at PMRF and S. Martin (SPAWAR) collected acoustic data on the PMRF bottom-mounted hydrophones. In this project, these data were analyzed to detect, characterize, and track minke whale calls. A minke boing detector and 3D model-based tracker was implemented. Acoustically derived positions were compared with SPA WAR position estimates (using the MM3 2D time-of-arrival tracking method). The MM3 2D tracker gave similar boing position estimates to the 3D model-based tracker. The localized boings were within the range for which direct paths exit and for which the constant-SSP TOA method (used by MM3 2D) is expected to give reasonable position estimates. The importance of using model-based tracking to get accurate position estimates increases with the range of the animal from the hydrophones, with hydrophone spacing, and with increasing complexity of sound speed profiles.

Download or read book Tracking Marine Mammals Using Passive Acoustics written by Eva-Marie Nosal and published by . This book was released on 2007 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Listening to Whales written by Rianna Elizabeth Burnham and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The acoustic sense is vital to all life processes for whales. It defines their 'active space', and the extent and nature of interactions with their surroundings. Yet, we are still learning the basics of most species' acoustic behaviours and vocal repertoires. The ecology of gray whales (Eschrichtius robustus) is well known, however vocal behaviours are not well described outside of breeding lagoons. Bottom-stationed acoustic monitoring devices were deployed in Clayoquot Sound, west coast Vancouver Island to explore acoustics use outside of these areas. During migration the use of low frequency moan calls are prevalent, perhaps for group cohesion, with lead whales guiding followers. During the summer more inter-group calls (knocks, upsweeps) are employed. Here I explored the use of 'motherese' calls between cow-calf pairs, and how this may mirror the weaning process. Photoperiod, increased ambient noise, threat perception, and vessel and aircraft presence elicited acoustic responses. Calling was also altered by social, behavioural, and physiological state. These results begin to show gray whales to be acoustically sensitive, with highly nuanced vocalising behaviours. Acoustic methods afford monitoring at times and in places that would otherwise be impossible, and lends themselves to the study of rare or cryptic species. Ocean gliders with passive acoustic capacity were used to explore deep-coastal and shelf-break waters for large whale species. Humpback whales (Megaptera novaeangliae) were common on the shelf, whereas calls from fin (Balaenoptera physalus), blue (Balaenoptera musculus), sperm (Physeter macrocephalus), and possibly sei whales (Balaenoptera borealis) were heard in more offshore locations. Concurrent habitat data steams help establish area use and importance to these species. The surveys focus on submarine canyons that are thought to aggregate prey. Calls denote whale presence, whereas call type may suggest behaviour and habitat use. Calls described for feeding and breeding were heard for fin and blue whales, with distinct temporal distribution. Acoustic techniques complement other ecological methods and can fill existing knowledge gaps in whale life histories. It can also help quantify the effect of human activities on whale populations and ocean soundscapes. These findings will inform management actions. I provide examples of management links to acoustic-ecological research.

Download or read book The Detection and Analysis of Fin Whale Vocalizations Recorded Offshore of Galicia written by Jamie Burford and published by . This book was released on 2015 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Clicks and Currents written by Rebecca Emily Cohen and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The western North Atlantic is a dynamic region characterized by the Gulf Stream western boundary current and inhabited by a diverse host of odontocete, or toothed whale, top predators. Their habitats are highly exploited by commercial fisheries, shipping, marine energy extraction, and naval exercises, subjecting them to a variety of potentially harmful interactions. Many of these species remain poorly understood due to the difficulties of observing them in the pelagic environment. Their habitat utilization and the impacts of anthropogenic activities are not well known. Over the past decade, passive acoustic data has become increasingly utilized for the study of a wide variety of marine animals, and offers several advantages over traditional line-transect visual survey methods. Passive acoustic devices can be deployed at offshore monitoring sites for long periods of time, enabling detection of even rare and cryptic species across seasons and sea states, and without altering animal behaviors. Here we utilized a large passive acoustic data set collected across a latitudinal habitat gradient in the western North Atlantic to address fundamental knowledge gaps in odontocete ecology. I approached the problem of discriminating between species based on spectral and temporal features of echolocation clicks by using machine learning to identify novel click types, and then matching these click types to species using spatiotemporal correlates. I was able to identify novel click types associated with short-beaked common dolphins, Risso's dolphins, and short-finned pilot whales in this way. Next I characterized temporal patterns in presence and activity for ten different species across our monitoring sites at three different temporal scales: seasonal, lunar, and diel. I observed spatiotemporal separation of apparent competitors, and complex behavioral patterns modulated by interactions between the seasonal, lunar, and diel cycles. Finally I investigated the relationships between species presence and oceanographic covariates to predict habitat suitability across the region, and explored niche partitioning between potentially competitive species. The insights gained here significantly advance our understanding of toothed whale ecology in this region, and can be used for more effective population assessments and management in the face of anthropogenic threats and climate change.