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Introduction
Publications
Publications (340)
Body size is key to many life-history processes, including reproduction. Across species, climate change and other stressors have caused reductions in the body size to which animals can grow, called asymptotic size, with consequences for demography. A reduction in mean asymptotic length was documented for critically endangered North Atlantic right w...
Human caregivers interacting with children typically modify their speech in ways that promote attention, bonding, and language acquisition. Although this "motherese," or child-directed communication (CDC), occurs in a variety of human cultures, evidence among nonhuman species is very rare. We looked for its occurrence in a nonhuman mammalian specie...
Vocalisation rates were measured from North Atlantic right whales (Eubalaena glacialis) in spring 1999-2000 in the Great South Channel and off Cape Cod, USA, and in summer 1999-2000 in the Bay of Fundy, Canada. Vocalisations were classed as either ‘moans’, ‘low-frequency (LF) calls’ or ‘gunshots’. Towed hydrophone recordings (36.1 hours) were made...
Deep diving toothed whales evolved to predate on the biggest biomass on Earth in the Deep-Scattering-Layer (DSL) and Benthic-Boundary-Layer (BBL). The behavioural ecology of these more than 20 species of air-breathing predators might include
interspecific competition leading to spatial segregation or coexistence. Here we used DTAGs to investigate...
Toothed whales routinely discriminate and select prey via echolocation. Over a decade, the harbor porpoise Freja in Fjord and Bælt, Kerteminde, Denmark participated in a series of target discrimination experiments involving metal objects. Different from experiments in which the subjects were constrained to be stationary, Freja’s free and voluntary...
How do dolphins attend to echos and ignore background noise? Is the process similar to how humans attend to conversations in a crowded room? Studies of human selective attention have highlighted endogenous brain processes modulating the magnitude of early responses to sounds in auditory evoked potentials (AEPs), yet these rely on task-specific inst...
Most auditory evoked potential (AEP) studies in echolocating toothed whales measure neural responses to outgoing clicks and returning echoes using short-latency auditory brainstem responses (ABRs) arising a few ms after acoustic stimuli. However, little is known about longer-latency cortical AEPs despite their relevance for understanding echo proce...
Some studies of how human activities can affect wild free-ranging animals may be considered to have potential negative outcomes too severe to be ethically studied. This creates a societal dilemma involving choices between continuing risky activities with high uncertainty about their potential effects on wildlife, often with considerable associated...
During the COVID-19 pandemic, changes in vessel activity and associated noise have been reported globally. Sarasota Bay is home to a large and increasing number of recreational vessels as well as a long-term resident community of bottlenose dolphins, Tursiops truncatus. Data were analyzed from two hydrophones to compare the soundscape during the CO...
Assessing cumulative effects of human activities on ecosystems is required by many jurisdictions, but current science cannot meet regulatory demands. Regulations define them as effect(s) of one human action combined with other actions. Here we argue for an approach that evaluates the cumulative risk of multiple stressors for protected wildlife popu...
During the COVID-19 pandemic, decreases in large vessel activity and low-frequency noise have been reported globally. Sarasota Bay is home to a large and increasing number of recreational vessels, as well as a long-term resident community of bottlenose dolphins, Tursiops truncatus. We analyzed data from two hydrophones to compare the soundscape dur...
Common bottlenose dolphins (Tursiops truncatus) produce individually distinctive signature whistles that are learned early in life and that help animals recognize and maintain contact with conspecifics. Signature whistles are the predominant whistle type produced when animals are isolated from conspecifics. Health assessments of dolphins in Sarasot...
Baleen whalesBaleen whales are specialized to find and exploit preyPrey that form dense patches seasonally within broad ocean areas. Most populations have an annual reproductive cycleAnnual reproductive cycle that separates their breeding seasonBreeding season from their feeding seasonFeeding season, often with long-distance migrationsMigrationsbet...
Stemming from the traditional use of field observers to score states and events, the study of animal behaviour often relies on analyses of discrete behavioural categories. Many studies of acoustic communication record sequences of animal sounds, classify vocalizations, and then examine how call categories are used relative to behavioural states and...
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ABSTRACT
In humans, understanding a voice amidst competing sounds depends on parsing the sound mixture into “streams” representing each source's content. Streaming can be influenced by top-down attentional focus, while acoustic features can affect streaming percepts through bottom-up, automatic processing of pitch, timbre, and loca...
Auditory masking by anthropogenic noise may impact marine mammals relying on sound for important life functions, including echolocation. Animals have evolved antimasking strategies, but they may not be completely effective or cost-free. We formulated seven a priori hypotheses on how odontocete echolocation behavior could indicate masking. We addres...
Major progress has been made since the publication of noise exposure criteria by Southall et al. (2007) in addressing the probability and severity of marine mammal behavioral responses to measured noise exposures. New methodological developments for studying behavioral responses have broadened the spatial, temporal, and population scales of potenti...
How learning affects vocalizations is a key question in the study of animal communication and human language. Parallel efforts in birds and humans have taught us much about how vocal learning works on a behavioural and neurobiological level. Subsequent efforts have revealed a variety of cases among mammals in which experience also has a major influ...
Two previous studies suggest that bottlenose dolphins exhibit an “oddball” auditory evoked potential (AEP) to stimulus trains where one of two stimuli has a low probability of occurrence relative to another. However, they reported oddball AEPs at widely different latency ranges (50 vs 500 ms). The present work revisited this experiment in a single...
Modern active sonar systems can (almost) continuously transmit and receive sound, which can lead to more masking of important sounds for marine mammals than conventional pulsed sonar systems transmitting at a much lower duty cycle. This study investigated the potential of 1-2 kHz active sonar to mask echolocation-based foraging of sperm whales by m...
An expanded nonmilitary hydrophone network provides new opportunities to understand the variability and trends of ocean sound and the effects of sound on marine organisms.
The interference between the direct path and the sea surface reflection of a signal as measured by a receiver is called Lloyd's Mirror effect (LME). It results in a frequency-dependent interference pattern that can be observed in a spec-trogram. LME depends on the receiver depth, signal source depth, signal frequency, and slant range between source...
Animal-mounted data logging devices are used to study the behaviour, physiology, and ecology of free-ranging marine mammals, as well as their reactions to controlled exposures. It is important to consider whether collected data are representative of natural behaviour or biased by responses to tagging. In species with stereotypical diving behaviour,...
Fin whales were once abundant in the seas to the southwest of Portugal, but whaling activities decreased their numbers considerably. Acoustic data from ocean bottom seismometers provide an opportunity to detect fin whales from their notes, data that would otherwise be logistically challenging and expensive to obtain. Based on inter-note interval an...
Developing the next generation framework for modelling marine mammal responses to noise: A workshop to identify key elements for future models – A report of the pre-conference workshop held at the World Marine Mammal Conference, Barcelona, 8 December 2019.
The objective of the workshop was to discuss how marine mammal responses to
noise could be m...
Fear of predation can induce profound changes in the behaviour and physiology of prey species even if predator encounters are infrequent. For echolocating toothed whales, the use of sound to forage exposes them to detection by eavesdropping predators, but while some species exploit social defences or produce cryptic acoustic signals, deep-diving be...
It's the prey that matters
Although many people think of dinosaurs as being the largest creatures to have lived on Earth, the true largest known animal is still here today—the blue whale. How whales were able to become so large has long been of interest. Goldbogen et al. used field-collected data on feeding and diving events across different types...
Toothed whales have evolved flexible biosonar systems to find, track and capture prey in diverse habitats. Delphinids and phocoenids adjust inter-click intervals and source levels gradually while approaching prey. In contrast, deep-diving beaked and sperm whales maintain relatively constant inter-click intervals and apparent output levels during th...
Humans and songbirds learn to sing or speak by listening to acoustic models, forming auditory templates, and then learning to produce vocalizations that match the templates. These taxa have evolved specialized telencephalic pathways to accomplish this complex form of vocal learning, which has been reported for very few other taxa. By contrast, the...
Anthropogenic underwater noise has increased over the past century, raising concern about the impact on cetaceans that rely on sound for communication, navigation, and locating prey and predators. Many terrestrial animals increase the amplitude of their acoustic signals to partially compensate for the masking effect of noise (the Lombard response),...
The International Quiet Ocean Experiment (IQOE) is the first international project designed to help coordinate and gain synergy from isolated passive acoustic observations and experiments taking place worldwide. IQOE implementation has so far consisted mainly of four components: (1) creation of focused working groups, (2) endorsement of national an...
Killer whales (KW) may be predators or competitors of other cetaceans. Since their foraging behavior and acoustics differ among populations (‘ecotypes’), we hypothesized that other cetaceans can eavesdrop on KW sounds and adjust their behavior according to the KW ecotype. We performed playback experiments on long-finned pilot whales (Globicephala m...
Estimating the number of animals impacted by a stressor typically involves combining a dose–response function with information about the distribution of animals and of the stressor.
Regulators often prefer a single threshold to a full dose–response function, but much of the variability observed in the threshold at which different individuals respon...
Impact assessments for sonar operations typically use received sound levels to predict behavioural disturbance in marine mammals. However, there are indications that cetaceans may learn to associate exposures from distant sound sources with lower perceived risk. To investigate the roles of source distance and received level in an area without frequ...
Air-breathing marine predators must balance the conflicting demands of oxygen conservation during breath-hold and the cost of diving and locomotion to capture prey. However, it remains poorly understood how predators modulate foraging performance when feeding at different depths and in response to changes in prey distribution and type. Here, we use...
Managing the nonlethal effects of disturbance on wildlife populations has been a long‐term goal for decision makers, managers, and ecologists, and assessment of these effects is currently required by European Union and United States legislation. However, robust assessment of these effects is challenging. The management of human activities that have...
Bottlenose dolphins (Tursiops truncatus) are highly versatile breath-holding predators that have adapted to a wide range of foraging niches from rivers and coastal ecosystems to deep-water oceanic habitats. Considerable research has been done to understand how bottlenose dolphins manage O2 during diving, but little information exists on other gases...
Interdisciplinary perspectives on the capacity to perceive, appreciate, and make music.
Research shows that all humans have a predisposition for music, just as they do for language. All of us can perceive and enjoy music, even if we can't carry a tune and consider ourselves “unmusical.” This volume offers interdisciplinary perspectives on the capac...
Passive acoustic monitoring with widely-dispersed hydrophones has been suggested as a cost-effective method to monitor population densities of echolocating marine mammals. This requires an estimate of the area around each receiver over which vocalizations are detected—the “effective detection area” (EDA). In the absence of auxiliary measurements en...
Exposure to underwater sound can cause permanent hearing loss and other physiological effects in marine animals. To reduce this risk, naval sonars are sometimes gradually increased in intensity at the start of transmission (‘ramp-up’). Here, we conducted experiments in which tagged humpback whales were approached with a ship to test whether a sonar...
Minke whales are difficult to study and little information exists regarding their responses to anthropogenic sound. This study pools data from behavioural response studies off California and Norway. Data are derived from four tagged animals, of which one from each location was exposed to naval sonar signals. Statistical analyses were conducted usin...
The ocean science community has invested heavily in coordinating systems developed to make ocean observations. The Global Ocean Observing System (GOOS) is a research program developed to coordinate ocean observing systems. Expert panels identify requirements for the systems in terms of Essential Ocean Variables (EOVs). The absence of sound in the l...
Animals with stable relationships need mechanisms to stay in touch when separated. Five decades of research suggest that signature whistles are likely candidates for serving this contact-calling purpose in bottlenose dolphins. However, difficulties identifying the vocalizing individual and measuring inter-animal distances have hindered tests of cal...
Bottlenose dolphins (Tursiops truncatus) produce a wide array of sounds, including clicks for echolocation and whistles for communication, both of which have been studied intensively. However, sounds other than whistles and echolocation clicks have received less attention, probably due to their high variability. These include the class of sounds lo...
Passive acoustic monitoring has become an increasingly prevalent tool for estimating density of marine mammals, such as beaked whales, which vocalize often but are difficult to survey visually. Counts of acoustic cues (e.g., vocalizations), when corrected for detection probability, can be translated into animal density estimates by applying an indi...
All odontocetes produce echolocation clicks as part of their vocal repertoire. In this paper the authors analysed inter-click-intervals in recordings from suction cup tags with a focus on the first inter-click interval of each click train. The authors refer to shorter first inter-click intervals as short first intervals (SFIs). The authors found th...
The development of guidelines for mitigating noise impacts on marine fauna requires data about the biological relevance of noise effects and about the practicality of mitigation options. Recent expansion of scientific knowledge has shown that noise effects vary among animals with different behavioral ecophysiology. Beaked whales exemplify that some...
Modern long-range naval sonars are a potential disturbance for marine mammals and can cause disruption of feeding in cetaceans. We examined the lunge-feeding behaviour of humpback whales Megaptera novaeangliae before, during and after controlled exposure experiments with naval sonar by use of acoustic and motion sensor archival tags attached to eac...
Substantial recent progress has been made in directly measuring behavioral re - sponses of free-ranging marine mammals to sound using controlled exposure experiments. Many studies were motivated by concerns about observed and potential negative effects of military sonar, including stranding events. Well-established experimental methods and increasi...
Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Society for Marine Mammalogy for personal use, not for redistribution. The definitive version was published in Marine Mammal Science 33 (2017): 653–668, doi:10.1111/mms.12376.
Without a means of studying large whales in a controlled experimental environment, less is understood about their sound production mechanisms than is understood about those of smaller odontocetes. To describe call production behavior in fin whales, we used a recent technique that correlates fast-sampling accelerometer signals from tags with concurr...
The ocean acoustic Lloyd's Mirror effect (LME) is produced by interference between the direct-path and the sea surface phase-reversed reflection of a sound as observed at a receiver. It results in a frequency-dependent interference pattern that can be observed in a spectrogram. Many studies have found variations of spectral characteristics of the 2...
The ocean acoustic Lloyd?s Mirror effect (LME) is produced by interference between the direct-path and the sea surface phase-reversed reflection of a sound as observed at a receiver. It results in a frequency-dependent interference pattern that can be observed in a spectrogram. Many studies have found variations of spectral characteristics of the 2...
Early studies that categorized odontocete pulsed sounds had few means of discriminating signals used for biosonar-based foraging from those used for communication. This capability to identify the function of sounds is important for understanding and interpreting behavior; it is also essential for monitoring and mitigating potential disturbance from...
This study characterizes daytime acoustic and dive behavior of pantropical spotted dolphins (Stenella attenuata) in Hawai‘i using 14.58 h of data collected from five deployments of digital acoustic recording tags (DTAG3) in 2013. For each tagged animal, the number of whistles, foraging buzzes, dive profiles, and dive statistics were calculated. Sta...
Social interactions among animals can influence their response to disturbance. We investigated responses of long-finned pilot whales to killer whale sound playbacks and two anthropogenic sources of disturbance: tagging effort and naval sonar exposure. The acoustic scene and diving behaviour of tagged individuals were recorded along with the social...
Vocal learning is usually studied in songbirds and humans, species that can form auditory templates by listening to acoustic models and then learn to vocalize to match the template. Most other species are thought to develop vocalizations without auditory feedback. However, auditory input influences the acoustic structure of vocalizations in a broad...
Passive acoustic monitoring has become an increasingly prevalent tool for estimating the density of marine mammals, such as beaked whales, which vocalise often but are difficult to survey visually. Acoustic cue counts, when corrected for detection probability, can be translated into an estimate of animal density by applying an individual cue produc...
The time and energetic costs of behavioral responses to incidental and experimental sonar exposures, as well as control stimuli, were quantifi ed using hidden state analysis of time series of acoustic and movement data recorded by tags (DTAG) attached to 12 sperm whales (Physeter macrocephalus) using suction cups. Behavioral state transition modeli...
One of the founding fathers of marine mammal bioacoustics, William Watkins, carried out pioneering work with William Schevill at the Woods Hole Oceanographic Institution for more than four decades, laying the groundwork for the present day field. One of the lasting achievements of his career was the Watkins Marine Mammal SoundDatabase, a resource t...
Background For marine animals, acoustic communication is critical for many life functions, yet individual calling behavior is poorly understood for most large whale species. These topics are important for understanding whale social behavior and can also serve as a baseline for behavioral studies assessing whale response to disturbance. Using a new...
Controlled exposure experiments using 1 to 2 kHz, sonar signals were conducted with 11 humpback whales (Megaptera novaeangliae), one minke whale (Balaertoptera acutorostrata), and one northern bottlenose whale (Hyperoodon ampullatus) during three field trials from 2011 to 2013. Ship approaches without sonar transmissions, playbacks of killer whale...
In mitigating the risk of sonar operations, the behavioral response of cetaceans is one of the major knowledge gaps that needs to be addressed. The 3S-Project has conducted a number of controlled exposure experiments with a realistic sonar source in Norwegian waters from 2006 to 2013. In total, the following six target species have been studied: ki...