The Behavioural Response of Australian Fur Seals to Motor Boat Noise

Australian fur seals breed on thirteen islands located in the Bass Strait, Australia. Land access to these islands is restricted, minimising human presence but boat access is still permissible with limitations on approach distances. Thirty-two controlled noise exposure experiments were conducted on breeding Australian fur seals to determine their behavioural response to controlled in-air motor boat noise on Kanowna Island (39°10′S, 146°18′E). Our results show there were significant differences in the seals' behaviour at low (64–70 dB) versus high (75–85 dB) sound levels, with seals orientating themselves towards or physically moving away from the louder boat noise at three different sound levels. Furthermore, seals responded more aggressively with one another and were more alert when they heard louder boat noise. Australian fur seals demonstrated plasticity in their vocal responses to boat noise with calls being significantly different between the various sound intensities and barks tending to get faster as the boat noise got louder. These results suggest that Australian fur seals on Kanowna Island show behavioural disturbance to high level boat noise. Consequently, it is recommended that an appropriate level of received boat sound emissions at breeding fur seal colonies be below 74 dB and that these findings be taken into account when evaluating appropriate approach distances and speed limits for boats

Avoidance responses of minke whales to 1–4 kHz naval sonar

The SOCAL project was funded by the US Navy Chief of Naval Operations Environmental Readiness Division and US Office of Naval Research. The 3S project was funded by the Norwegian Ministry of Defence, the US Office of Naval Research, the Netherlands Ministry of Defence and DGA French Ministry of Defence. The MOCHA project was funded by the US Office of Naval Research. Tyack received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.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 using Mahalanobis distance to compare overall changes in parameters summarising dive behaviour, avoidance behaviour, and potential energetic costs of disturbance. Our quantitative analysis showed that both animals initiated avoidance behaviour, but responses were not associated with unusual dive behaviour. In one exposed animal the avoidance of the sonar source included a 5-fold increase in horizontal speed away from the source, implying a significant increase in metabolic rate. Despite the different environmental settings and exposure contexts, clear changes in behaviour were observed providing the first insights into the nature of responses to human noise for this wide-ranging species.PostprintPeer reviewe

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

North Pacific right whale ( Eubalaena japonica

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

Behavioural responses of humpback whales to food-related chemical stimuli

Publisher's version (útgefin grein)Baleen whales face the challenge of finding patchily distributed food in the open ocean. Their relatively well-developed olfactory structures suggest that they could identify the specific odours given off by planktonic prey such as krill aggregations. Like other marine predators, they may also detect dimethyl sulfide (DMS), a chemical released in areas of high marine productivity. However, dedicated behavioural studies still have to be conducted in baleen whales in order to confirm the involvement of chemoreception in their feeding ecology. We implemented 56 behavioural response experiments in humpback whales using two food-related chemical stimuli, krill extract and DMS, as well as their respective controls (orange clay and vegetable oil) in their breeding (Madagascar) and feeding grounds (Iceland and Antarctic Peninsula). The whales approached the stimulus area and stayed longer in the trial zone during krill extract trials compared to control trials, suggesting that they were attracted to the chemical source and spent time exploring its surroundings, probably in search of prey. This response was observed in Iceland, and to a lesser extend in Madagascar, but not in Antarctica. Surface behaviours indicative of sensory exploration, such as diving under the stimulus area and stopping navigation, were also observed more often during krill extract trials than during control trials. Exposure to DMS did not elicit such exploration behaviours in any of the study areas. However, acoustic analyses suggest that DMS and krill extract both modified the whales’ acoustic activity in Madagascar. Altogether, these results provide the first behavioural evidence that baleen whales actually perceive prey-derived chemical cues over distances of several hundred metres. Chemoreception, especially olfaction, could thus be used for locating prey aggregations and for navigation at sea, as it has been shown in other marine predators including seabirds.This research was funded by the Fondation Total (www.fondation.total.com), grant #144903 to A.C., and the Ministère de l'Enseignement Supérieur et de la Recherche (www.enseignementsup-recherche.gouv.fr) to B.B., Bourse doctorale. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer Reviewe

Progression in humpback whale song structure and complexity on a subarctic feeding ground in Northern Norway

Male humpback whales (Megaptera novaeangliae) sing structurally complex songs traditionally associated with low latitude breeding grounds. This vocal behaviour is increasingly reported outside these areas. All singers in a given population sing the same version of a song that is constantly evolving with modifications on different levels within the song structure. This study provides the first detailed analysis of humpback whale songs recorded on a subarctic feeding ground in Northern Norway. Passive acoustic data from the Lofoten-Vesterålen Ocean Observatory were collected using bottom-moored underwater hydrophone and included the months January – June 2018 and December 2018 – January 2019. Two measures of the song structure were examined: (1) sequence similarities using the Levenshtein distance and (2) song complexity. More than 440 hours of recordings spread over 199 days were inspected for humpback whale song occurrence using a semi-automated approach. Overall, 750 hours of humpback whale singing activity was detected spanning 79 days between December and April. The first singing activity was detected beginning of January 2018, followed by a peak in February and was heard until mid-April. No song was found during the summer months and was detected again in December 2018, continuing over January 2019. Song structure analyses resulted in a total of 18 distinct themes; 11 themes in 2018 and 7 themes in 2019. The themes clustered into two song types, one for each year, suggesting an event of rapid song progression. As all sampled animals were singing the same version of the song within each year, this might indicate that the singers are either from the same breeding population or that song conformation was performed before the study period. Song complexity increased as songs evolved over the months in 2018 and decreased drastically between the years 2018 and 2019. The results confirm that humpback whale song can be heard over multiple months and years in Northern Norway. Finally, this study identified song progression on a shared subarctic feeding ground, indicating potential song exchange between the North Atlantic humpback whale populations already before reaching their breeding grounds. Tracing changes in whale song will help to undercover the drivers underlying this vocal display and contribute to the understanding of animal culture and its evolution

The Sonar Model for Humpback Whale Song Revised

Why do humpback whales sing? This paper considers the hypothesis that humpback whales may use song for long range sonar. Given the vocal and social behavior of humpback whales, in several cases it is not apparent how they monitor the movements of distant whales or prey concentrations. Unless distant animals produce sounds, humpback whales are unlikely to be aware of their presence or actions. Some field observations are strongly suggestive of the use of song as sonar. Humpback whales sometimes stop singing and then rapidly approach distant whales in cases where sound production by those whales is not apparent, and singers sometimes alternately sing and swim while attempting to intercept another whale that is swimming evasively. In the evolutionary development of modern cetaceans, perceptual mechanisms have shifted from reliance on visual scanning to the active generation and monitoring of echoes. It is hypothesized that as the size and distance of relevant events increased, humpback whales developed adaptive specializations for long-distance echolocation. Differences between use of songs by humpback whales and use of sonar by other echolocating species are discussed, as are similarities between bat echolocation and singing by humpback whales. Singing humpback whales are known to emit sounds intense enough to generate echoes at long ranges, and to flexibly control the timing and qualities of produced sounds. The major problem for the hypothesis is the lack of recordings of echoes from other whales arriving at singers immediately before they initiate actions related to those whales. An earlier model of echoic processing by singing humpback whales is here revised to incorporate recent discoveries. According to the revised model, both direct echoes from targets and modulations in song-generated reverberation can provide singers with information that can help them make decisions about future actions related to mating, traveling, and foraging. The model identifies acoustic and structural features produced by singing humpback whales that may facilitate a singer’s ability to interpret changes in echoic scenes and suggests that interactive signal coordination by singing whales may help them to avoid mutual interference. Specific, testable predictions of the model are presented

Diet Analysis of Stranded Bottlenose Dolphins (\u3ci\u3eTursiops truncatus\u3c/i\u3e) in Virginia

This study describes the diet of bottlenose dolphins (Tursiops truncatus) stranded in Virginia via stomach content analysis and considers factors such as proportion of numerical abundance and reconstructed mass, frequency of occurrence, average reconstructed prey size, prey diversity and quantity, and otolith degradation code. Fish size was estimated via regression equations established from local fish collected during the study that derive wet weight directly from otolith length or width. Squid size is estimated from previously published equations. Soniferous fishes dominated the diet, especially Atlantic croaker, spot, and seatrout spp., adding evidence to the theory that bottlenose dolphins passively listen for their prey. Noise pollution should be an important consideration for the conservation of this species. The diet was influenced by ontogenetic and seasonal changes. Prey that are relatively difficult to capture or not available to calves due to habitat, such as striped bass or longfin inshore squid, were absent in the diet of that age class. However, easy to capture prey, such as spot, became progressively less important with age. Seasonal variation in the diet was observed, with differences likely being due to changes in prey availability (due to seasonal migrations) and detectability (due to increased vocalizing during spawning) rather than changes in prey preference. Lastly, the stomachs of dolphins with external evidence of an entangling interaction contained a significantly higher proportion of recently ingested fish (using otolith code as a proxy) than those that did not. The presence of recently ingested prey is commonly referenced as an indicator of peracute underwater entrapment; however, this is the first study to quantitatively establish a significant relationship. The data presented in this study promise to enhance policy and management by establishing baseline information on natural history as well as a quantitatively assessed indicator for peracute underwater entrapment that can be referenced to study local shifts in natural history or incidence of bycatch

Comportamiento vocal de la ballena jorobada, Megaptera novaeangliae (Cetacea: Mammalia) : características y variación intrapoblacional en el Parque Nacional Natural Uramba- Bahía Málaga, Pacífico colombiano

Spa: Los sonidos y las señales acústicas cumplen un papel muy importante en la comunicación, la crianza, la alimentación, la orientación y la reproducción en los mamíferos marinos. Una de las especies con comunicación vocal más compleja es la ballena jorobada, Megaptera novaeangliae, la cual incluye la emisión de sonidos sociales y cantos, los cuales han sido caracterizados para muchas poblaciones, pero aún existen vacíos de información en sitios como el Pacífico colombiano (ej. Parque Nacional Natural Uramba-Bahía Málaga). De esta manera, el objetivo de esta tesis fue caracterizar el comportamiento vocal de la ballena jorobada (Megaptera novaeangliae) en el Parque Nacional Natural Uramba-Bahía Málaga, Pacífico colombiano, en la temporada reproductiva 2021. El objetivo fue responder a los siguientes interrogantes: ¿Cuáles son las características del comportamiento vocal de M. novaeangliae en el Parque Nacional Natural Uramba, Bahía Málaga?; ¿Existe variabilidad individual (distintos cantores) ó inter-grupal (entre grupos) en el comportamiento vocal de M. novaeangliae en el Parque Nacional Natural Uramba-Bahía Málaga? Y ¿Podría existir alguna variación del comportamiento vocal en relación con el tiempo y su entorno sonoro antropogénico. El estudio se realizó durante la temporada reproductiva de 2021 (31 días) en las horas luz del día, se siguieron grupos de ballenas y se registró su comportamiento vocal y los sonidos y ruidos de su entorno (paisaje sonoro) mediante el uso de hidrófonos, se identificaron los cantores y se complementaron las grabaciones de los sonidos con observaciones visuales. Se graficaron espectogramas y se identificaron las características de las vocalizaciones y el patrón de los cantos y de los sonidos que realizan los individuos de ballenas mediante programas estadísticos como RStudio y RavenPro V 1.5. Se realizaron modelos lineales para evaluar sí existen diferencias entre los sonidos por grupo y entre cantores. Los resultados de la investigación se exponen en el capítulo II, donde se muestran de manera amplia los principales hallazgos y se discuten los mismos para aportar insumo al conocimiento del comportamiento vocal de las ballenas jorobadas en Colombia y en la región y son un soporte para acciones de manejo y conservación de esta especie, objeto de conservación del área protegida.Bibliografía y webgrafía al final de cada capítulo.MagisterMagister en Ciencias Biológica

Acoustic Ecology of Humpback Whales (Megaptera novaeangliae) in the Hawaiian Archipelago.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017