Article

JNCC guidelines for minimising the risk of injury and disturbance to marine mammals from seismic surveys: We can do better

Authors:
  • Fisheries and Oceans Canada, Dartmouth, Canada
  • Whalesafari AS / Aarhus University
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... As the use of seismic equipment overlaps with many important habitats for marine mammals worldwide [31], many marine mammals are regularly exposed to airgun noise and there is a large and recognized potential for adverse effects (e.g. [1,23,42,43]). The present results confirm that there are substantial medium-to-high frequency components in airgun pulses, overlapping with the range of best hearing of harbor seals and harbor porpoises [39,40,41]. ...
... In most countries, current mitigation measures to reduce the risk of injury from airguns include a shut-down zone of some hundred meters around the survey ship; 500 m in case of the UK regulation [42]. If marine mammals are sighted within this zone the seismic activity must be stopped. ...
Article
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Airguns used in seismic surveys are among the most prevalent and powerful anthropogenic noise sources in marine habitats. They are designed to produce most energy below 100 Hz, but the pulses have also been reported to contain medium-to-high frequency components with the potential to affect small marine mammals, which have their best hearing sensitivity at higher frequencies. In shallow water environments, inhabited by many of such species, the impact of airgun noise may be particularly challenging to assess due to complex propagation conditions. To alleviate the current lack of knowledge on the characteristics and propagation of airgun pulses in shallow water with implications for effects on small marine mammals, we recorded pulses from a single airgun with three operating volumes (10 in<sup>3</sup>, 25 in<sup>3</sup> and 40 in<sup>3</sup>) at six ranges (6, 120, 200, 400, 800 and 1300 m) in a uniform shallow water habitat using two calibrated Reson 4014 hydrophones and four DSG-Ocean acoustic data recorders. We show that airgun pulses in this shallow habitat propagated out to 1300 meters in a way that can be approximated by a 18log(r) geometric transmission loss model, but with a high pass filter effect from the shallow water depth. Source levels were back-calculated to 192 dB re µPa<sup>2</sup>s (sound exposure level) and 200 dB re 1 µPa dB L<sub>eq-fast</sub> (rms over 125 ms duration), and the pulses contained substantial energy up to 10 kHz, even at the furthest recording station at 1300 meters. We conclude that the risk of causing hearing damage when using single airguns in shallow waters is small for both pinnipeds and porpoises. However, there is substantial potential for significant behavioral responses out to several km from the airgun, well beyond the commonly used shut-down zone of 500 meters.
... As the use of seismic equipment overlaps with many important habitats for marine mammals worldwide [31], many marine mammals are regularly exposed to airgun noise and there is a large and recognized potential for adverse effects (e.g. [1,23,42,43]). The present results confirm that there are substantial medium-to-high frequency components in airgun pulses, overlapping with the range of best hearing of harbor seals and harbor porpoises [39,40,41]. ...
... In most countries, current mitigation measures to reduce the risk of injury from airguns include a shut-down zone of some hundred meters around the survey ship; 500 m in case of the UK regulation [42]. If marine mammals are sighted within this zone the seismic activity must be stopped. ...
Article
Full-text available
The data accompanies the paper "Characteristics and propagation of airgun pulses in shallow water with implications for effects on small marine mammals" published in PLOS ONE, July 27, 2015, DOI: 10.1371/journal.pone.0133436. Data is provided as 1 second .wav files (50 ms before peak to 950 ms after peak) for each airgun pulse filtered with a 5 Hz 4-pole high pass filter in Adobe Audition 3 (version 3.0). Information about setup for the recordings is provided as pdf. .
... These measures were based on established guidelines for high energy seismic surveys (High Energy Seismic Survey Team 1999), which were, however, recognized as outdated in the EIR. Such guidelines are commonly used when planning seismic surveys, regardless of their effectiveness for a particular circumstance (Wright & Cosentino 2015). Key proposed mitigation measures included avoiding areas of high (observed) marine mammal density, ramp-up of air gun activity, and shutdown if marine mammals were observed within the Exclusion Zone. ...
... The specific details of each case will differ, as assessments under the expanded framework in Fig. 6 must also consider overarching species-specific and case-specific factors (Box 1). These may include the need for daily food intake or resting (Yasui & Gaskin 1986, White & Seymour 2003, Tyne et al. 2015, the biological role of acoustic communication that may be masked or disrupted (Clark et al. 2009, Wright & Cosentino 2015, Gomez et al. 2016, or the presence of other threats nearby (Wright et al. 2007, Slooten 2013. Some of these considerations can be evaluated based on established biological science, such as the relationship between metabolic rate and mammalian body size (Kleiber 1932, White & Seymour 2003. ...
Article
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As awareness of the effects of anthropogenic noise on marine mammals has grown, research has broadened from evaluating physiological responses, including injury and mortality, to considering effects on behavior and acoustic communication. Most mitigation efforts attempt to minimize injury by enabling animals to move away as noise levels are increased gradually. Recent experiences demonstrate that this approach is inadequate or even counterproductive for small, localized marine mammal populations, for which displacement of animals may itself cause harm. Seismic surveys within the ranges of harbor porpoise Phocoena phocoena in California and Maui dolphin Cephalorhynchus hectori maui in New Zealand highlight the need to explicitly consider biological risks posed by displacement during survey planning, monitoring, and mitigation. Consequences of displacement are poorly understood, but likely include increased stress and reduced foraging success, with associated effects on survival and reproduction. In some cases, such as the Critically Endangered Maui dolphin, displacement by seismic activities risks exposing the re -maining 55 dolphins to bycatch in nearby fisheries. Similar concerns about military and industrial activities exist for island-associated species such as melon-headed whales Peponocephala electra in Hawai'i; shelf-break associated species such as Cuvier's beaked whales Ziphius cavirostris off the US Atlantic coast, and whales foraging in coastal habitats, such as the Critically Endangered western gray whale Eschrichtius robustus. We present an expanded framework for considering disturbance effects that acknowledges scientific uncertainty, providing managers and operators a more robust means of assessing and avoiding potential harm associated with both displacement and direct effects of intense anthropogenic noise exposure.
... In other parts of the world, to protect marine fauna, policies have been released stating minimum required standards for seismic survey companies to adhere to (Weir & Dolman, 2007). The Department of the Environment in the United Kingdom published the Joint Nature Conservation Committee (JNCC) guidelines in 1995 to reduce the impacts of anthropogenic noise from oil and gas exploration surveys (Parsons et al., 2009;Wright & Cosentino, 2015). A number of countries and regions subsequently followed suit and released their own guidelines with varying degrees of protection (Weir & Dolman, 2007). ...
... African EIAs generally follow the JNCC guidelines with a few modifications and have to be approved by PASA as the governing authority after stakeholder engagement. The JNCC guidelines are outdated (Parsons et al., 2009;Wright & Cosentino, 2015), and ideally South ...
Conference Paper
Algoa Bay, South Africa has a diverse array of marine top-predators, including Indo-Pacific bottlenose dolphin (Tursiops aduncus), Indian Ocean humpback dolphin (Sousa plumbea), long-beaked common dolphin (Delphinus capensis), Bryde’s whale (Balaenoptera brydei), southern right whale (Eubalaena australis), humpback whale (Megaptera novaeangliae), African penguins (Spheniscus demersus) and Cape fur seals (Arctocephalus pusillus). Algoa Bay also has a number of anthropogenic activities that may acoustically affect marine fauna, including seismic surveys conducted to locate oil and gas reserves in the sub-surface of the seabed. We modelled the estimated level of sound received by marine top-predators observed during a seismic survey conducted in 2013. To do this, we used an airgun array simulation tool (Agora) to model the source level of the airguns and a sound propagation model RAMSGeo to model the transmission loss. Using recently published sound exposure criteria, we determined whether marine fauna encountered by Marine Mammal Observers during this survey were exposed to sound exposure levels that could result in temporary or permanent hearing damage. The results of this study are aimed at informing the development of legal instruments to mandate acoustic modelling before conducting seismic and other acoustic activities in South Africa’s exclusive economic zone, particularly in relation to sensitive biodiverse areas, or proximities to marine protected areas.
... There is considerable uncertainty regarding the effectiveness of these 'standard' mitigation methods in relation to OWF developments (Parsons et al., 2009;Wright and Cosentino, 2015). The effectiveness of MMOs is heavily dependent on weather and associated sighting conditions, and even under good conditions, sighting rate decreases with sighting distance (Barlow et al., 2001). ...
... Reliable detection using PAM systems can also be problematic and Wright and Cosentino (2015) provide a summary of the issues that arise in using PAM for mitigation . One issue is that animals not vocalising will remain undetected. ...
Technical Report
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Increasing scale and complexity of offshore wind farms (OWF) and on-going concern for European Protected Species (EPS) has led to interest in identifying alternative mitigation strategies to commonly used visual observation and acoustic detection methods for marine mammals. Acoustic Deterrent Devices (ADDs) have been identified as a potentially effective tool for a number of small cetacean species, but research has been lacking for some other key species that occur within prospective OWF sites. A controlled exposure experiment (CEE) was designed and implemented to test the efficacy of the Lofitech ADD as a potential mitigation tool for the minke whale during piling operations. During August and September 2016, visual tracking of minke whales was undertaken in Faxaflói Bay, Iceland by a team of researchers on the R.V. Song of the Whale. When a focal animal had been identified and tracked for at least 30 minutes, the ADD was deployed at a distance of 1,000 m in order to expose the animal to the ADD signal. The behaviour of the focal animal was tracked during a control, treatment and post-treatment phase in order to understand the potential reactions to the ADD signal. Biological parameters such as inter-sequence interval, inter-blow interval, net swim speed, and measures of path predictability were recorded and later analysed to examine the behaviour in detail. In addition, the variable ‘away speed’ was derived in order to determine both the directionality and the longevity of any effect on the behaviour of the focal animal. The ADD itself was fully characterised in the field. The unit deployed was found to have a source root mean square (rms) sound pressure level of 198 dB re 1 μPa re 1m, for a fundamental frequency of 14.6 kHz. The pulse length had an average of 752 ms. As noted in the literature, variability among individual units is expected. A total of 46 minke whales were successfully tracked. Of these, 15 included successful deployments of the ADD. The focal animal moved away from the ADD deployment site in all cases. A significant increase in net swim speed during the treatment phase was observed, with whales increasing their speed by an average of 7.4 kmh-1. The away speed variable showed a significant increase in speed during the second half of the treatment phase, indicating that animals both increase their speed and the directness of their path in relation to exposure to the ADD signal. The results highlight that the Lofitech ADD is effective at evoking a deterrence response in minke whales, suggesting that such devices could be effective at reducing any potential for injurious effects from exposure to subsea noise generated during pile-driving activity at OWF sites.
... These impacts can range from short-term and long-term displacement (Teilmann and Carstensen, 2012;Thompson et al., 2013a) through to temporary or permanent threshold shifts in hearing (Kastak et al., 2005;Kastelein et al., 2014;Lucke et al., 2009), depending on the animals' proximity to the activity and the activity type. These concerns continue to grow as increasing pressure is exerted on the marine environment (Dolman and Simmonds, 2010;Wright and Cosentino, 2015;Wright and Kyhn, 2015) by activities such as the installation of marine renewable energy devices (Witt et al., 2012), surveys for, and extraction of, fossil fuels (oil and gas) (Culloch et al., 2016), harbour maintenance and expansion (Pirotta et al., 2013) and increased shipping noise (Merchant et al., 2014). ...
... The growing number of calls for a better understanding of marine mammal population dynamics and how potential impacts may be influencing behaviour and proxies for fitness has coincided with an increase in anthropogenic pressures on the marine environment (Dolman and Simmonds, 2010;Wright and Cosentino, 2015;Wright and Kyhn, 2015). When designing monitoring programmes it is becoming evident that identifying how populations are using areas is extremely important and that studies should not solely focus on displacement patterns (New et al., 2013;Pirotta et al., 2014b). ...
Article
During the construction of a pipeline from an offshore gas field in northwest Ireland, shore-based watches and opportunistic boat-based photo-identification surveys for bottlenose dolphins Tursiops truncatus were undertaken. Seven years of data were used to investigate the influence of Construction-Related Activity (CRA) on the occurrence of dolphins in the bay where the pipeline made landfall. CRA varied substantially over the seven years and included dredging, pipe-laying, and rock armouring as well as seismic surveys. While individual activities could not be examined in isolation, there was no evidence of aggregated CRA or season influencing occurrence, despite a greater number of CRA days during summer months. There was weak support for the influence of year, but lower occurrence rates did not correspond to years with more CRA days, or vice versa. The uncorrected (marked animals, only) and corrected (accounting for unmarked individuals) annual abundance estimates with the lowest coefficient of variation were 67 (95% CI = 62–84; CV = 0.08) and 140 (95% CI = 106–174; CV = 0.12) in 2010, which was comparable to estimates from a neighbouring region on the west coast of Ireland. Of the well-marked individuals approximately 50% were re-sighted in two or more years and re-sightings within years were as high as 70%. Overall, there was little evidence to suggest that the extended period of CRA resulted in a short- or long-term reduction in the occurrence of dolphins within the bay. However, given the relatively coarse spatial and temporal scale of the CRA data it was not possible to assess fine-scale movements, such as redistribution within the bay in response to CRA within the immediate area. To better inform management and mitigation practices, greater emphasis should be placed on designing robust monitoring programmes that focus beyond fine-scale displacement as the sole indicator of an impact.
... Therefore, researchers have developed monitoring techniques. In addition, at present, marine projects are instructed to monitor their operational area for the marine mammal's presence so that mitigation efforts can be applied [2,3]. Marine mammal observers (MMOs) are trained and instructed to monitor the sea surface for marine animals such as whales [4]. ...
Article
Full-text available
A key aspect of ocean protection consists in estimating the abundance of marine mammal population density within their habitat, which is usually accomplished using visual inspection and cameras from line-transect ships, small boats, and aircraft. However, marine mammal observation through vessel surveys requires significant workforce resources, including for the post-processing of pictures, and is further challenged due to animal bodies being partially hidden underwater, small-scale object size, occlusion among objects, and distracter objects (e.g., waves, sun glare, etc). To relieve the human expert’s workload while improving the observation accuracy, we propose a novel system for automating the detection of beluga whales (Delphinapterus leucas) in the wild from pictures. Our system relies on a dataset named Beluga-5k, containing more than 5.5 thousand pictures of belugas. First, to improve the dataset’s annotation, we have designed a semi-manual strategy for annotating candidates in images with single (i.e., one beluga) and multiple (i.e., two or more belugas) candidate subjects efficiently. Second, we have studied the performance of three off-the-shelf object-detection algorithms, namely, Mask-RCNN, SSD, and YOLO v3-Tiny, on the Beluga-5k dataset. Afterward, we have set YOLO v3-Tiny as the detector, integrating single- and multiple-individual images into the model training. Our fine-tuned CNN-backbone detector trained with semi-manual annotations is able to detect belugas despite the presence of distracter objects with high accuracy (i.e., 97.05 mAP@0.5). Finally, our proposed method is able to detect overlapped/occluded multiple individuals in images (beluga whales that swim in groups). For instance, it is able to detect 688 out of 706 belugas encountered in 200 multiple images, achieving 98.29% precision and 99.14% recall.
... JNCC, 2017), such as soft-start procedures (also known as "ramp up"), whereby the source level is gradually increased (with the intent to displace animals before harmful levels are reached), and the establishment of a surveillance zone in which a marine mammal observer will monitor visually and/or acoustically for marine mammals prior to and during the activity. However, these in situ measures have been criticised as arbitrary and evidence for their efficacy is lacking (Wright & Cosentino, 2015). Some developers have also used acoustic deterrent devices (ADDs) to displace animals prior to the activity, with the intent of reducing the risk of auditory injury. ...
Article
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Underwater noise pollution poses a global threat to marine life and is a growing concern for policy makers and environmental managers. Evidence is mounting of noise‐induced habitat loss, heightened physiological stress, masking of biologically important sound (e.g. for communication, predator/prey detection), auditory injury, and in extreme cases, direct or indirect mortality (Southall et al. 2007; Popper et al. 2014). Initial studies focused on charismatic megafauna (particularly marine mammals), but in recent years effects have been discovered in other taxa and at lower trophic levels, including various fish species (Popper et al. 2014), functionally important marine crustaceans (Solan et al. 2016), and zooplankton (McCauley et al. 2017). This article is protected by copyright. All rights reserved.
... Up-calls are frequencymodulated upsweeps in the 50-250 Hz frequency band [3], and detection of up-calls has been shown to be the most effective mechanisms for determining whale presence in critical habitats [4,5]. Monitoring, usually involves realtime information with the goal of minimizing ship strikes or the potential harm from seismic exploration [8]. ...
Article
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This paper describes ongoing work to investigate the development of a complex system designed for extracting information from large acoustic datasets. The system, called DeLMA is based on integrating advanced machine learning with high performance computing (HPC). The goal of this work is to provide the capability to accurately detect and classify whale sounds in large acoustics datasets collected using underwater sensors. The case study for this work is focused on detecting the acoustic communication signals of the North Atlantic Right Whale, Eubalaena glacialis, and uses data collected in the Stellwagen Bank National Marine Sanctuary (SBNMS), USA. A summary of the work done for developing a complex detection-classification system and brief description of several algorithms that are used for classifying whale sounds will be covered. A brief discussion on how standard detection algorithms can be incorporated, with no special modifications, into the HPC system for analysis will be mentioned, and two new right whale detection methods are presented, based on continuous region analysis (CRA) and histogram of oriented gradients (HOG). This paper presents a first-hand look at applying the DeLMA system and these algorithms on a large dataset containing over 60,000 channel-hours of acoustic data from the SBNMS. Results from these new detection methods are compared against Baseline algorithms. With the development of the DeLMA system, sound archives can now be explored using a powerful distributed processing architecture. This advancement will allow for rapid execution and visualization of the data using seasonal graphs called diel plots, which show the distribution of detections on a time-of-day vs. time-of-year plane. Diel plots of Baseline, CRA and HOG algorithm results reveal various large-scale features of the seasonality of whale calling behavior. Results are summarized and the authors discuss future areas for study, especially those relate to handling other big passive acoustic data projects.
... Few studies have been able to quantify the long-term effects on cetaceans of exposure to man-made marine noise. Whilst brief or single acute exposures to sound may injure individual animals, long-term continuous noise from multiple sources is potentially more serious as it could cause changes to behavior and habitat use that could affect whole populations [215]. ...
Article
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This review provides an overview of the Mediterranean diversity and conservation status of cetaceans, and the value associated with their conservation and non-consumptive use. The Mediterranean Sea is one of the world's diversity hotspots; its biodiversity is increasingly under threat in the whole region and key species as cetaceans are under challenge for conservation. All the identified threats are interlinked and cumulatively contribute to the habitat degradation as well as reduced health status of the cetaceans that live there. Whales and dolphins, defined as charismatic megafauna, flag species, apex predators and bio indicators of the marine environment health are demanding social substantial changes. Needs are for spatial prioritization within a comprehensive framework for regional conservation planning, the acquisition of additional information identifying critical habitats in data-poor areas and for data deficient species, and addressing the challenges of establishing transboundary governance and collaboration in socially, culturally and politically complex conditions. This paper also examines research gaps, questions and issues (population abundance estimates, as well as the biological, ecological, physiological characteristics) surrounding cetacean species in the context of biodiversity conservation and highlights the need for targeted conservation management actions to reduce sources of disturbance by key threatening processes in the Mediterranean Sea. The ‘precautionary principle’ must be adopted at all levels in attempts to mitigate impacts and thus provides scope for the translation of the principle into operational measures. As natural entities, cetaceans have their objective intrinsic value, not humanly conferred.
... Guidelines may appear to lack statute, but regulatory authorities increasingly ensure they are binding legally via their licencing agreements for industrial activities; consequently, failure to comply with these requirements can result in substantial fines and/or influence future licencing decisions. These JNCC guidelines, however, have been criticised recently (Wright and Cosentino 2015). ...
... To prevent potentially adverse effects on marine life, caused by the acoustic energy emitted by these sources [6], much effort has been devoted to marine mammal mitigation, leading to several national and international regulations [7]. Often, during a survey, seismic operators are legally required to monitor for the presence of protected animals within specific ranges, generally 500 m from the source location [8]. ...
Conference Paper
Seismic sources are routinely employed by the oil and gas industry to identify hydrocarbon reserves beneath the seabed, and by researchers to image the sub-seabed for geophysics and to identify geo-hazards such as tsunami-generating areas. For mitigation purposes, it is paramount to identify animals in the water column, but they can be missed by surface observations (if they are diving or in bad weather) or by Passive Acoustic Monitoring (if they remain silent). For operational reasons, it is also important to know about any other sizeable objects below the water surface. Seismic sources emit high-amplitude broadband sounds, typically below 300 Hz, directed toward the seabed. They can also radiate energy up to 20 kHz into the water column, and it can be used as a “source of opportunity”. We use these higher frequencies (between 500 Hz to 20 kHz) to investigate their potential in identifying a variety of mid-water targets, with data from surveys conducted in challenging environments (two in shallow waters, 7–25 m deep, one in deep water, >1,500 m deep) with seismic sources up to 1,760 cubic inches in volume. The shallow-water surveys used a fixed source and freely drifting buoys, whereas the deep-water survey used a towed source with passive acoustic monitoring (PAM) vessel closely follow the seismic vessel to record data. The time spreads of individual shots recorded and the SNR at frequencies between 20 Hz – 20 kHz were compared between the surveys. Based on target strengths of potential targets at different ranges, and on benchmarked models of acoustic propagation, 2-D plots of measured vs. expected levels can be used to detect “hidden” targets of different sizes (from 0.5 to 20 m). The analyses suggest that, at 500 Hz, it is possible to confidently detect mid-water targets within the exclusion zone, and potentially going much further, to as deep as 2 km and as far as 2 km from the source. This has important implications for real-time mitigation and protection of marine mammals, which can be detected even if they are submerged and silent.
... Localized and short-term behavioral responses such as movement toward or away from the sound source or a change in vocalization rates have been reported for some cetaceans during seismic surveys (Richardson et al., 1995;Gordon et al., 1998;Nowacek et al., 2007;Southall et al., 2007;Barry, Cucknell, & Clark, 2012;Castellote, Clark, & Lammers, 2012;Blackwell et al., 2013Blackwell et al., , 2015Thompson et al., 2013;Robertson et al., 2013;Cerchio, Strindberg, Collins, Bennett, & Rosenbaum, 2014;Pirotta, Brookes, Graham, & Thompson, 2014;Wole & Myade, 2014;Dunlop et al., 2015Dunlop et al., , 2016Muir et al., 2015Muir et al., , 2016Finneran et al., 2015;Gailey et al., 2016). However, the long-term consequences of airgun sounds on marine mammals are mostly unknown, and the effectiveness of mitigation measures are largely uncertain (Cato et al., 2013;Nowacek et al., 2013;Wright & Consentino, 2015). ...
Article
Full-text available
Although the wider Eastern Tropical Pacific has been systematically surveyed during summer/fall, relatively little effort has focused on shelf and slope waters of Nicaragua and Costa Rica. Such data are useful for establishing baseline information and assessing potential changes in cetacean occurrence and distribution relative to natural (e.g., El Niño-Southern Oscillation, climate change) and anthropogenic factors. A visual-acoustic survey for cetaceans occurred as part of a monitoring and mitigation program during an academic geophysical seismic study off Nicaragua and Costa Rica, during November-December 2004. Approximately 2 067 cetaceans representing at least seven species were seen in 75 groups during 373 h (3 416 km) of daytime observations from the seismic research vessel (R/V) Maurice Ewing. The humpback whale (Megaptera novaeangliae) and the pantropical spotted dolphin (Stenella attenuata) were the most frequently sighted species (30 % of all groups sighted); both were seen in shelf waters < 100 m deep and in slope waters. The bottlenose dolphin (Tursiops truncatus; 10 % of sightings) was the third most frequently sighted species and was only seen in water > 100 m deep. In addition, sightings were made of spinner dolphins (S. longirostris), short-beaked common dolphins (Delphinus delphis), Risso’s dolphins (Grampus griseus), short-finned pilot whales (Globicephala macrorhynchus), and unidentified dolphins and whales. Unconfirmed sightings of a minke whale (Balaenoptera acutorostrata) and a pod of false killer whales (Pseudorca crassidens) were also recorded. An additional six groups of dolphins (50 % confirmed to species, all pantropical spotted dolphins) were made during 187 h (1 549 km) of observation effort during darkness, two of which were detected within 30 m of the vessel bow using a night vision device. A total of 217 cetacean detections occurred during 633 h of passive acoustic monitoring. A small concentration of 12 humpback whales was seen in eight groups, and two humpbacks were recorded singing in the Gulf of Fonseca on 9 December 2004. To our knowledge, such concentrations of humpback whales, particularly singing humpbacks, have not been previously reported in this specific area. In addition, a humpback mother-calf pair, likely from the Northern Hemisphere population, was seen off Northern Costa Rica on 25 November 2004. Although cetacean sighting rates were significantly different during seismic and non-seismic periods even when corrected for differential detection probability related to sea conditions, our survey results do provide information to address previous data gaps on cetacean occurrence in shelf and slope waters off the Pacific coast of Central America during late fall.
... In general, these protocols list a series of actions to be taken by specialized personnel (Marine Mammals Observers and Passive Acoustic Monitoring operators) to reduce exposure of marine mammals to potentially dangerous noise levels during the active phase of seismic surveys. Critical readings of these guidelines (Wright and Cosentino, 2015) and review of results have already been published (Stone, 2015). Nowacek et al. (2015) suggested ways to assess appropriate impact thresholds while stressing the importance of baseline data as a key aspect of reaching scientifically reliable conclusions about the risks to marine life from seismic surveys. ...
Article
Concern is growing that marine fauna can be affected by noise such as naval sonar, pile driving or geophysical surveys, among others. Literature reports a variety of animal reactions to human noise (from apparently null or negligible to strong). However, conclusive results on its effects on marine mammals at individual and population level are still lacking. In 2015, the Italian Environmental Impact Assessment Commission mandated seismic operators apply a standard scientific protocol comparing marine mammal presence before, during, and after offshore seismic survey. For 60 days before and after the survey, marine mammals are monitored using visual and acoustic methods. One or more acoustic autonomous recorders, depending on area size, must also be deployed throughout the three phases for continuous monitoring. Consistent data gathered from many surveys will enable robust statistical analysis of results. Diffusion of this monitoring method internationally would improve the study of far-reaching, intense, low frequency noise.
... These include the mandatory assignment of marine mammal observers on seismic survey vessel and the use of "soft-starts", where power levels of airguns are slowly built up to operational levels over at least 20 minutes, "to give adequate time for marine mammals to leave the vicinity" 15 . Recent evidences however suggest these requirements may not be sufficient, as observers sometimes lack adequate training, or may have limited power over the action of the vessel in some companies, while soft-starts assume that animals can, and are willing to, move away from the disturbance, which is not necessarily the case 17,18 . ...
... The methods to quantify environmental impacts vary according to bioindicators (Cooper et al., 2009), criteria of impact significance (Liu et al., 2012), and consideration of cumulative effects (Jones, 2016). There has been increasing attention directed towards the potential impacts of ocean noise on marine fauna (Williams et al., 2015), with low-frequency acute sound from activities such as marine seismic surveys being of particular concern (Gordon et al., 2003;Nowacek et al., 2015;Wright and Cosentino, 2015;Hawkins and Popper, 2016;Carroll et al., 2017;McCauley et al., 2017). ...
Article
Marine seismic surveys are a fundamental tool for geological research, including the exploration of offshore oil and gas resources, but the sound generated during these surveys represents a source of noise pollution in the marine environment. Recent evidence has shown that seismic surveys may negatively affect some cetaceans, fish and invertebrates, although the magnitude of these impacts remains uncertain. This paper applies a case study on marine seismic impacts (the Gippsland Marine Environmental Monitoring (GMEM) project) to the critical assessment of the advantages and challenges of field-based methods in the context of future research and management priorities. We found that an interdisciplinary approach, using both conventional (e.g. dredging) and innovative (e.g. autonomous imagery) experimental components, make for more robust interpretations and also provide a failsafe in case of limited suitable data (e.g. equipment issues related to image acquisition). Field observational studies provide an unparalleled capability to undertake ecologically realistic research, although their practical challenges must be considered during research planning. We also note the need for appropriate environmental baselines and accessible time-series data to account for spatiotemporal variability of environmental and biological parameters that may mask effects, as well as the need for a standardised technique in sound monitoring and equipment calibration to ensure accuracy and comparability among studies.
... Documented sperm whale habitat along the Atlantic Margin to the west of Ireland largely overlaps with areas which are now of growing interest to the oil and gas industry regarding their potential for resource extraction. The impact on marine mammals of some of the industry's activities, in particular seismic surveying which uses intense underwater sound sources over protracted periods, is a cause of concern Harwood and Wilson, 2001;Wright and Mel Cosentino, 2015). In this regard a knowledge of sperm whale density and distribution is important for understanding, managing and mitigating potentially negative impacts on the species. ...
Article
Full-text available
Previous studies off western Ireland have suggested that substantial numbers of, mainly male, sperm whales may be found in these habitats. Whaling vessels operating from shore stations in Ireland in the early 20th century frequently caught sperm whales in oceanic waters. It is likely that this North Atlantic region contains important foraging habitats for this species, and that mature males must also migrate through this area moving between breeding grounds to the south and other feeding areas further north. Increasingly, these offshore waters are being utilised and potentially impacted by human industrial activities. For example, as inshore resources are depleted and technology improves, both the commercial fishing and the oil and gas industry are becoming more active in deeper waters beyond the continental margin. It is important therefore to better understand the biology and ecology of sperm whales in these more remote areas. However, their offshore location and deep diving habits, together with weather constraints in the exposed Atlantic, make research difficult. New sperm whale density estimates are reported using data from six seasonal passiveacoustic surveys carried out in two successive years (2015 and 2016). These covered a corridor approximately 110km wide which bounded a major portion of Ireland’s continental shelf break. Towed hydrophone line-transect methodologies were used, which have proven to be highly effective for surveying sperm whales in offshore waters and in poor weather conditions. Target motion analysis was applied to calculate the ranges of vocalising whales from the survey tracklines and the effective strip half-width calculated across all surveys was 7,958m. The study area was surveyedin three blocks and animal densities within these blocks varied between 1 and 4.6 individuals per 1,000km2 (CV 0.34 and 0.21 respectively) with an overall mean density in waters deeper than 300m of 3.2 individuals per 1,000km2(CV 0.04). These robust density estimates are the first of their kind for Irish waters and are similar to those reported in other Atlantic areas considered significant for this species. These results emphasise the significance of this region as sperm whale habitat. The results of this study should be used to inform the future sustainable development and management of Ireland’s offshore Atlantic.
... These mitigation measures may reduce acute impacts on particular (protected) species or taxonomic groups (Wright and Cosentino, 2015), and should be used if appropriate. However, they do not address effects on other taxa, nor the cumulative and long-term effects of repeated lowlevel noise exposure from multiple sources. ...
Article
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Underwater noise pollution is becoming globally recognised as a significant threat to aquatic ecosystems and the resources they provide. The effects of noise pollution extend from blue whales to zooplankton, impacting threatened species and affecting key industries including fisheries and ecotourism. In response, policymakers in some jurisdictions have made substantive high-level commitments to address noise pollution, however the implementation of noise reduction measures (noise abatement) remains limited. To support the development of effective noise management policies, this paper explores the economic and policy context to noise abatement in three major noise-generating industries: shipping, offshore windfarm construction, and seismic surveying for oil and gas. In each case, tractable policy options are identified which make considered use of command-and-control and incentive-based measures in light of the available noise abatement methods. Drawing on instructive examples from terrestrial noise management and other sectors, it is concluded that such measures offer the most promising long-term solution to deliver existing and future policy commitments to manage cumulative levels of underwater noise pollution.
... Documented sperm whale habitat along the Atlantic Margin to the west of Ireland largely overlaps with areas which are now of growing interest to the oil and gas industry regarding their potential for resource extraction. The impact on marine mammals of some of the industry's activities, in particular seismic surveying which uses intense underwater sound sources over protracted periods, is a cause of concern Harwood and Wilson, 2001;Wright and Mel Cosentino, 2015). In this regard a knowledge of sperm whale density and distribution is important for understanding, managing and mitigating potentially negative impacts on the species. ...
Article
Sperm whales Physeter macrocephalus and long-finned pilot whales Globicephala melas are the most abundant species among the community of deep-diving cetaceans occurring off the west coast of Ireland, northeast Atlantic. To address a knowledge gap on these elusive species in an area subject to increasing levels of anthropogenic noise, fixed bottom-mounted autonomous acoustic recorders were deployed from 2014 to 2016 at 13 locations. Acoustic data were collected over 2410 cumulative days, for a total of 9179 h of recordings, with sperm whale clicks and pilot whale whistles detected on 79 and 53% of the days monitored, respectively. Diel, lunar and seasonal effects on the acoustic occurrence of sperm whales and long-finned pilot whales were investigated for individual recording sites and for each recording year using generalised estimating equations. Large differences in acoustic occurrence across stations for both species highlighted the existence of more critical locations throughout the year, especially to the north of the shelf edge. Temporally, significant modulations were found for both species at all scales investigated, but the lack of consistency across the study area emphasises the need to exercise great caution when inferring general tendencies based on local patterns. The variability of spatio-temporal patterns indicates a flexibility in the distribution of sperm whales and long-finned pilot whales off the west coast of Ireland, highlighting the challenge in establishing management and mitigation measures and stressing the need of long-term, year-round monitoring.
... This is at odds with the reality, which is a general lack of either regulation or mitigation of underwater sound, except in the case of a very few activities such as seismic surveys, pile driving, and some naval sonar. Even in these cases, mitigation actions are often ineffective or misdirected and could be replaced by simpler and more effective measures [3]. For example, in the case of seismic surveys, small reductions in source level (e.g., 3 dB) would achieve a greater reduction in injury risk than shutdowns and reduce impacts on the ecosystem as a whole [4]. ...
... ADDs are also included in this category, since they are also active sonar devices known to affect marine life. ADDs may be deployed with the intention to deter seals from fish farms (Findlay et al., 2018), or to displace marine mammals from areas where more intense noise is going to occur (Wright and Cosentino, 2015), e.g. prior to pile-driving activity (Dähne et al., 2017;Graham et al., 2019). ...
Article
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Underwater noise pollution from impulsive sources (e.g. explosions, seismic airguns, percussive pile driving) can affect marine fauna through mortality, physical injury, auditory damage, physiological stress, acoustic masking, and behavioural responses. Given the potential for large-scale impact on marine ecosystems, some countries are now monitoring impulsive noise activity, coordinated internationally through Regional Seas Conventions. Here, we assess impulsive noise activity in the Northeast Atlantic reported during 2015–2017 to the first international impulsive noise register (INR), established in 2016 under the OSPAR Convention. Seismic airgun surveys were the dominant noise source (67%-83% of annual activity) and declined by 38% during 2015–2017. Reported pile driving activity increased 46%. Explosions and sonar/acoustic deterrent devices both had overall increases in reported activity. Some increases were attributable to more comprehensive reporting in later years. We discuss utilising the INR for risk assessment, target setting, and forward planning, and the implementation of similar systems in other regions.
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Marine mammals and sea turtles were documented as part of a monitoring and mitigation program during a seismic study offshore (~250 km) from Vancouver island, British Columbia, during August–September 2009. Forty-one marine mammals in nine groups were sighted. Dall’s Porpoise (Phocoenoides dalli) was the most frequently sighted species. A Sperm Whale (Physeter macrocephalus), a pod of Pacific White-sided Dolphins (Lagenorhynchus obliquidens), an unidentified toothed whale, a Northern Elephant Seal (Mirounga angustirostris), and a leatherback Turtle (Dermochelys coriacea) were also observed. These data augment current knowledge on the occurrence of marine mammals and sea turtles in the offshore waters of British Columbia.
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Guide de préconisations pour limiter l'impact des émissions acoustiques d'origine anthropique sur la faune marine, rédigé sous l'égide du Ministère français de la Transition Ecologique, ce rapport a pour objectif (1) de faire un état des lieux des émissions acoustiques générées par les activités industrielles en mer et des connaissances liées à ces émissions ; (2) de résumer l'état des connaissances sur les impacts du bruit sur la faune marine (des invertébrés aux mammifères marins) et d'identifier les axes à développer ; (3) de lister les mesures existantes pour éviter ou réduire les impacts et leurs degrés de maturité ; (4) de proposer des fiches synthétiques par activités recoupant les différentes informations mentionnées dans les points précédents. Ces différents points sont largement illustrés et résumés sous forme de tableaux récapitulatifs. Ce guide s'adresse aux services de l'Etat, gestionnaire d'aire marine, ONG, bureaux d'études ou tout autre structure ayant besoin d'informations sur les interactions bruit et faune marine. Une introduction aux notions élémentaires d'acoustique sous marine est également proposée pour les non spécialistes. Ce guide est disponible en français uniquement pour le moment, une version anglaise est en cours de rédaction.
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A guide to recommendations for limiting the impact of anthropogenic noise emissions on marine fauna, written under the patronage of the French Ministry of Ecological Transition, this work aims to (1) provide an overview of the acoustic emissions generated by industrial activities at sea and the knowledge related to these emissions; (2) to summarise the state of knowledge on the impacts of noise on marine fauna (from invertebrates to marine mammals) and to identify the research axis to be developed; (3) to list the existing measures to avoid or reduce impacts and their degree of maturity; (4) to propose summary sheets for each activity, cross-referencing the various information mentioned in the previous points. These different points are largely illustrated and summarised in the form of summary tables. This guide is intended for government departments, marine area managers, NGOs, consultancy firms and any other structure requiring information on noise and marine fauna interactions. An introduction to the basics of underwater acoustics is also provided for non-specialists.
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The Clymene dolphin (Stenella clymene) is endemic to warm Atlantic Ocean waters and is one of the least known delphinids. We reviewed existing published data (primarily strandings, captures, and bycatch) and unpublished sightings to examine the distribution, habitat, group size, seasonality, and pigmentation patterns of Clymene dolphins within the eastern tropical Atlantic (ETA). Following photographic verification, 84 confirmed and 8 probable at-sea sightings of ETA Clymene dolphins were analyzed. The documented records ranged from similar to 19 degrees N in central Mauritania to 14 degrees 26'S in southern Angola, confirming 14 ETA range states. At-sea sightings occurred in water depths of 437-5,000 m and at distances from shore of 21-937 km, corresponding with a continental slope and oceanic habitat. Sightings within the wider ETA region had year-round occurrence. Group size ranged from 3-1,000 animals, with 60.9% of groups comprising <= 50 animals. Photographic examination revealed a complex and variable pigmentation pattern in ETA Clymene dolphins, which contrasts with the simple tripartite pattern often described for this species. In particular, most ETA animals had a dark gray lateral stripe extending diagonally along the flank from the beak to the genital area and a conspicuous dark gray eye-flipper stripe of varying intensity and thickness. The at-sea sightings documented here significantly extend current knowledge of the distribution, ecology, and appearance of the Clymene dolphin.
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The ability to gather real-time and near real-time data on marine mammal distribution, movement, and habitat use has advanced significantly over the last two decades. These advancements have outpaced their adoption into a meaningful risk-based assessment framework so critically needed to support society's growing demands for a transition towards increased reliance on renewable energy. Marine acoustics have the capacity to detect, identify, and locate vocalizations over broad areas. Photogrammetric and image processing increases the ability to visually detect animals from surface or aerial platforms. Ecological models based upon long-term observational data coupled with static and remotely sensed oceanographic data are able to predict daily and seasonal habitat suitability. Extensive monitoring around anthropogenic activities combined with controlled experiments of exposure parameters (i.e., sound) supports better informed decisions on reducing effects. Population models and potential consequence modeling provide the ability to estimate the significance of individual and population exposure. The collective capacities of these emerging technical approaches support a risk ranking/risk management approach to monitoring and mitigating effects on marine mammals related to development activities. The monitoring paradigm related to many offshore energy-related activities, however, has long been spatially limited, situationally myopic, and operationally uncertain. A case evaluation process is used to define and demonstrate the changing paradigm of effective monitoring aimed at protecting living resources and concurrently providing increased certainty that essential activities can proceed in an efficient manner. Recent advances in both technologies and operational approaches are examined to delineate a risk-based paradigm, driven by a diversity of regional data inputs, that is capable of meeting the imperative for timely development of offshore wind energy. This article is protected by copyright. All rights reserved.
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Seismic surveys are widely used in marine geophysical oil and gas exploration, employing airguns to produce sound-waves capable of penetrating the sea floor. In recent years, concerns have been raised over the biological impacts of this activity, particularly for marine mammals. While exploration occurs in the waters of at least fifty countries where marine turtles are present, the degree of threat posed by seismic surveys is almost entirely unknown. To investigate this issue, a mixed-methods approach involving a systematic review, policy comparison and stakeholder analysis was employed and recommendations for future research were identified. This study found that turtles have been largely neglected both in terms of research and their inclusion in mitigation policies. Few studies have investigated the potential for seismic surveys to cause behavioural changes or physical damage, indicating a crucial knowledge gap. Possible ramifications for turtles include exclusion from critical habitats, damage to hearing and entanglement in seismic survey equipment. Despite this, the policy comparison revealed that only three countries worldwide currently include turtles in their seismic mitigation guidelines and very few of the measures they specify are based on scientific evidence or proven effectiveness. Opinions obtained from stakeholder groups further highlight the urgent need for directed, in-depth empirical research to better inform and develop appropriate mitigation strategies. As seismic surveying is becoming increasingly widespread and frequent, it is important and timely that we evaluate the extent to which marine turtles, a taxon of global conservation concern, may be affected.
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Offshore Exploration and Production (E&P) activities, such as seismic surveys and drilling, generate sound that can affect marine mammals in different ways. These effects range from permanent or temporary auditory impacts to disturbance or behavioral changes, and communication masking. Depending on the intensity and duration of these effects, and without implementation of appropriate mitigation measures, this can result in population-level consequences. The overarching objective of this study was to advance the protection of marine mammals during the implementation of E&P activities through the following themes: (1) enhancement of the state of knowledge of risk management, (2) efficacy of mitigation, (3) advanced monitoring technology, (4) implementation of advanced industry monitoring and mitigation measures and (5) measurement of heretofore unassessed E&P activities. In this study several marine mammal monitoring and mitigation programs associated with E&P projects are presented to further advance these themes. Topics being addressed include the use of autonomous camera systems for aerial monitoring of a narwhal population, long-term photo-identification studies of western gray whales to better understand site fidelity to their summer feeding grounds, mitigation of gray whales’ behavioral responses to a seismic survey near these feeding grounds and use of Passive Acoustic Monitoring to characterize seismic pulses and drilling activity as well as marine mammal presence in remote arctic areas. A synthesis of the main findings is provided that includes identification of future research needs. Conclusions and specific recommendations are made that will contribute to our ability to assess and mitigate risks of E&P sound to marine mammals.
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Background The Mediterranean subpopulation of fin whale Balaenoptera physalus (Linnaeus, 1758) has recently been listed as Vulnerable by the IUCN Red List of threatened species. The species is also listed as species in need of strict protection under the Habitat Directive and is one of the indicators for the assessment of Good Environmental Status under the MSFD. Reference values on population abundance and trends are needed in order to set the threshold values and to assess the conservation status of the population. Methods Yearly summer monitoring using ferries as platform of opportunity was performed since 2008 within the framework of the FLT Med Network. Data were collected along several fixed transects crossing the Western Mediterranean basin and the Adriatic and Ionian region. Species presence, expressed by density recorded along the sampled transects, was inspected for assessing interannual variability together with group size. Generalized Additive Models were used to describe density trends over a 11 years’ period (2008–2018). A spatial multi-scale approach was used to highlight intra-basin differences in species presence and distribution during the years. Results Summer presence of fin whales in the western Mediterranean area showed a strong interannual variability, characterized by the alternance of rich and poor years. Small and large groups of fin whales were sighted only during rich years, confirming the favorable feeding condition influencing species presence. Trends highlighted by the GAM can be summarized as positive from 2008 to 2013, and slightly negative from 2014 to 2018. The sub-areas analysis showed a similar pattern, but with a more stable trend during the second period in the Pelagos Sanctuary sub-area, and a negative one in the other two sub-areas. Our findings further confirm the need for an integrated approach foreseeing both, large scale surveys and yearly monitoring at different spatial scales to correct and interpret the basin wide abundance estimates, and to correlate spatial and temporal trends with the ecological and anthropogenic drivers.
Technical Report
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There is a clear and urgent need for a nationally co-ordinated and heightened focus on how the UK Government can ensure a secure, low carbon energy supply whilst protecting the environment. Ensuring secure energy supplies is one of seven Departmental Strategic Objectives of the Department for Energy and Climate Change (DECC). The Committee on Climate Change has signalled to Government that it needs to take immediate action to support the accelerated development of offshore renewable energy. It is, however, recognised that an increase in the development of renewable energy has to be achieved in a sustainable manner with due consideration given to meeting the requirements of other European and UK legislation. In the marine environment, the Marine Strategy Framework Directive’s goal to achieve Good Environmental Status of the EU’s marine waters by 2020 has particular relevance, as does the need for robust evidence to support the implementation of the Marine and Coastal Access Act 2009. Marine planning will set the direction for decision making to lead to efficient and sustainable use of our marine resources. There has been a rapid expansion of the offshore wind sector since the UK’s first offshore turbines were constructed off Blyth Harbour, off the Northumberland Coast. This has set the scene for offshore wind to play a major role in plans to ensure the UK‘s energy security and in meeting the UK Government’s targets. A number of large scale Round 3 offshore wind farm (OWF) developments have now been proposed and will need to be considered in marine planning process. Critical to achieving implementation of the above legislative and policy requirements is a need to consider potential cumulative effects arising from maritime activities, and in particular from large-scale developments. Cumulative effects assessment (CEA) can be defined as evaluating effects from multiple pressures and/or activities. This includes a requirement to evaluate the interaction of events separated in time and/or in space. This report provides a summary of the sensitivity of key environmental receptors (e.g. birds, mammals, fish, benthos and reptiles) arising from construction and operation of OWFs, including a specific assessment of receptors in the East of England marine plan areas. Existing approaches to CEA are reviewed, in particular their ability to fully account for the complexity of assessing the potential for cumulative effects arising from OWF developments. A conceptual framework was identified, based on the DPSIR approach for documenting potential cumulative effects of OWFs. This framework is used to describe the main steps for CEA within the context of marine planning. It is clear that no existing approaches to CEA can be applied without modification; however a bespoke approach might evolve from a hybrid of the available options supplemented by more novel approaches to fully account for the complexity of cumulative effects arising from OWF developments. Key evidence gaps in current knowledge essential for CEA are identified. Areas currently lacking in understanding include the potential impact of ‘refuge-effects’ of OWFs, the effects of noise and electromagnetic fields, the effect of altered habitat type on communities and a lack of data on distributions and behaviours of highly mobile species. A series of prioritised recommendations are provided with a proposed road map of priorities for addressing key gaps going forward. Recommendations include: 1. Develop methods to evaluate different sector-sector and pressure-pressure interactions. 2. Develop methods to help mitigate environmental impacts during the design of OWF arrays to help ‘design out’ potential cumulative effects. 3. Ensure current available data sets are recorded to MEDIN metadata standards to facilitate access. 4. Ensure assessments are based on agreed evidence and current knowledge and updated as new intelligence comes to light. 5. Produce definitive guidelines to facilitate consistency of approaches for determining potential cumulative impacts associated with licence applications. 6. Investigate the potential for significant ecosystem changes arising from the cumulative effects of large-scale OWF developments. 7. Use predictive modelling to consider trans-boundary cumulative effect. 8. Develop and encourage the use of innovative technologies to track highly mobile receptors (e.g. birds, mammals, reptiles and fish) for more complete and accurate coverage of distribution, behaviour and response to OWF development. 9. Assess the potential for new infrastructure from the development of OWFs to act as de-facto MPAs for benthic habitats. 10. Assess individual and cumulative effects of the installation and presence of new foundation types. 11. Model the potential or long-term cumulative effects of OWF construction and operational noise over extended spatial and temporal extents on marine mammals. 12. Develop the available bank of data on marine mammals by encouraging the collation, harmonisation and re-use of marine mammal observation data. 13. Model the potential for long-term cumulative effects of OWF construction noise over extended spatial and temporal extents on key fish species including early life-stages. 14. Collate existing information on turtle distributions and behaviour and determine whether there is any overlap with OWF development and the associated effect ranges. If there is significant overlap, model the cumulative effect of construction noise to determine the potential for adverse cumulative effects. 15. Determine if there is any overlap in bat distribution and OWF developments. If there is significant overlap, conduct a review and model the risk of cumulative effects arising from rotating blades on bats.
Conference Paper
Cetaceans rely on sounds for their survival. Marine environmental degradation due to increased noise levels, including noise from seismic surveys, is an issue of great concern. In many Latin American (LA) countries, these activities proceed without robust environmental impact assessments (EIAs) and effective mitigation plans to minimize impacts on marine life. Only Brazil and Peru have enacted statutory guidelines to mitigate such impacts within their national waters. Colombian environmental authorities impose adoption of JNCC Seismic Guidelines. Some countries and oil companies voluntarily adopt mitigation measures set in the legislation of other countries. EIAs are mandatory to obtain licenses for seismic surveys in 11 countries of the region; however, only Argentina, Brazil and Colombia have specific guidelines to conduct such EIAs but they still suffer some flaws. Application of EIAs, baseline surveillance and real-time monitoring and mitigation of seismic surveys by most LA countries is very poor. There is an urgency to increase awareness among LA countries and urge regulators to enact and enforce proper legislation for marine seismic survey activities. This paper supports the idea of an international legislation to regulate seismic surveys and make some recommendations that should be addressed by the international guidelines.
Article
Anthropogenic underwater noise levels have generally increased as industrial activities in the ocean have become more prevalent. Because of the central nature of sound in the lives of many marine animals, and the known and potential adverse impacts of noise, it is also gaining increased international recognition as an important global conservation issue. Here, a current compilation and synthesis of official documents, reports, and strategic plans from various intergovernmental, governmental, and international organizations, and noise-related projects and programs, demonstrate increasing efforts to understand anthropogenic underwater noise, and the mitigation and management measures that are being considered to reduce noise. While some entities aim to better understand and quantify underwater noise and its impacts, others have recommended explicit mitigation measures including spatio-temporal approaches to managing noise sources, and vessel quieting technologies. New approaches also include the development of certification or voluntary noise-reduction programs and agreements. We highlight four considerations that will better link the potential impacts of noise with corresponding mitigation and noise reducing efforts: 1) collaboration to address the transboundary and cumulative nature of underwater noise; 2) differing countries’ implementation capabilities for addressing noise; 3) time and intensity tradeoffs (e.g., louder noise for a shorter time period versus quieter but for longer); and 4) variable noise impacts depending on specific life history stages and life functions. Our review affirms the international consensus that anthropogenic underwater noise is a currently pervasive yet relatively transient form of pollution, the effects of which can be significantly reduced through effective mitigation and regulatory action.
Technical Report
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The rocky habitat is inhabited by a wide range of marine organisms and is the richest and most complex habitat along the Israeli Mediterranean coastline. This habitat comprises submerged rocky reefs and intertidal vermetid reefs, which together constitute an oasis in the biomass-poor eastern Mediterranean. The reefs provide shelter and breeding zones vital to the revival of marine populations, including many species of commercial value. Their ecological value is therefore immense. Because of its beauty and richness of life, the rocky habitat attracts large numbers of visitors by boat and on foot, as well as SCUBA divers. Rocky intertidal reefs also provide the shore essential protection against erosion. However, despite its importance, this habitat has been damaged by intensive human activity. This damage can be attributed to intensive and uncontrolled fishing - some of it using destructive fishing methods and equipment; the invasion of non-native species; accelerated water desalination and energy infrastructure development along the shore; and various types of debris and pollution. In addition, the physical break-up of the rock, which damages organisms attached to it, and the rise in sea level and water temperature further impact on the rocky habitats and the species they nurture. Biodiversity Action Plans (BAPs) are used in many countries to protect rocky habitats. In Israel, however, rocky habitats do not have adequate protection and as a result both they and their inhabitants are being decimated. The conservation of this unique and significant marine ecosystem requires an action plan to protect its biodiversity and enable it to be of benefit to man now and in the future. The BAP we propose focuses on six of the main factors impacting on the rocky habitat: fishing, solid waste pollution, coastal infrastructure development, physical damage, invading species, and industrial and municipal sewage effluents. The key targets of the BAP are to: • Increase the percentage of effective protection of rocky habitats within marine reserve areas; • Rehabilitate and protect biodiversity; • Establish a statutory and administrative system for effective and sustainable management. The BAP incorporates the outline of a policy for rocky habitat protection as well as suggestions on how to disseminate this information among decision makers. It also includes ideas for research, education and campaigning activities. The BAP calls for increased monitoring and enforcement, as well as regional and international measures to promote protection of biodiversity in the rocky habitat.
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Seismic surveys in search for oil or gas under the seabed, produce the most intense man-made ocean noise with known impacts on invertebrates, fish and marine mammals. No evidence to date exists, however, about potential impacts on seabirds. Penguins may be expected to be particularly affected by loud underwater sounds, due to their largely aquatic existence. This study investigated the behavioural response of breeding endangered African Penguins Spheniscus demersus to seismic surveys within 100 km of their colony in South Africa, using a multi-year GPS tracking dataset. Penguins showed a strong avoidance of their preferred foraging areas during seismic activities, foraging significantly further from the survey vessel when in operation, while increasing their overall foraging effort. The birds reverted to normal behaviour when the operation ceased, although longer-term repercussions on hearing capacities cannot be precluded. The rapid industrialization of the oceans has increased levels of underwater anthropogenic noises globally, a growing concern for a wide range of taxa, now also including seabirds. African penguin numbers have decreased by 70% in the last 10 years, a strong motivation for precautionary management decisions, including the exclusion of seismic exploratory activities within at least 100 km of their breeding colonies.
Technical Report
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A workshop on the “Status and Applications of Acoustic Mitigation and Monitoring Systems for Marine Mammals” was held November 17-19, 2009, sponsored by the Bureau of Energy Management, Regulation and Enforcement (BOEMRE) and attended by over 200 participants. The objectives of the workshop were stated as follows: “Learn about, discuss, and better understand the current status of acoustic hardware and software tools for marine mammal monitoring and mitigation as applied to offshore industries. This will include the capability, applicability, feasibility, availability, cost and other benefits and limitations of acoustic systems as they pertain to different marine mammal and operational contexts. The discussion will focus on currently available acoustic systems, along with some potentially beneficial applications under development.”
Technical Report
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The harbour porpoise (Phocoena phocoena) is the most numerous cetacean species in the North Sea. For reasons not well understood, it gradually disappeared from the southern North Sea during the 1950s, to make a spectacular return towards the end of the 20th century. The analysis of Belgian and Dutch sighting data, together with the results of research on the hundreds of animals washed ashore, yielded information on ecological aspects of the population, trends and threats. The recent increase in numbers in the southern North Sea is probably food related, and is believed to be due to an influx of porpoises from more northern waters. Strandings data seem to indicate that the influx consists for the main part of juveniles, with significantly more males than females. However, stranded pregnant females and numerous neonates indicate that some reproduction takes place in the southern North Sea. Currently, a clear seasonal pattern is apparent in the presence of porpoises. A peak in numbers in coastal waters of the southern North Sea is reached between February and April. In late spring a northward migration towards more offshore waters is observed, and by summer the number of porpoises in coastal waters has become low. In the Dutch Delta Area (Zeeland) a small resident population seems to have been established. Observations during 2007 and 2008 have indicated that the seasonal pattern might not be stable. Together with the return of the porpoise to the southern North Sea, a bycatch problem became apparent. Up to half of the stranded porpoises had been killed incidentally in fishing gear, a rate that justifies concerns. The main fishing gears responsible for the porpoise bycatch are gill- and tangle nets, considered otherwise as selective and relatively environmentally friendly. Next to a lack of data on the ecology of the porpoise, data are lacking on the true level of bycatch, and on the extent, and spatial and temporal distribution of relevant fishing methods. To obtain such data, research initiatives should be coordinated and standardised internationally. Basic research funds should be structural and be provided for a long time span. Currently protection initiatives are dispersed in many international nature conservation fora. Perhaps the best forum for the coordination of scientific research efforts in relation to porpoises in the North Sea would be ASCOBANS. For further developing measures, the most appropriate framework would be the European Community, given its competence in, and responsibilities for both fisheries and environmental matters. Also measures to prevent bycatch in recreational fisheries should be coordinated internationally. One of the most promising bycatch prevention measures is the use of pingers (acoustic alarms). However, many problems with their use remain, and currently they are not mandatory for most gill and tangle net fisheries in the southern North Sea. While currently only few Belgian and Dutch fishermen use gill- and tangle nets, this is gradually changing, due to environmental concerns of beamtrawling and especially the soaring gasoline prices (up to the end of 2008). Therefore it is likely that without effective protective measures, the porpoise bycatch in certain areas in the North Sea will increase. It is clear that disentangling the problems the harbour porpoise is facing, is a challenging task, given the combination of environmental, social, economical, political, legal and technical factors involved.
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This is the preliminary and the first study for understanding the effect of acoustic deterrent devices (pingers) on catch rates of fish (target turbot fish, Schophthalmus maeoticus and non target thornback ray, Raja clavata) and harbour porpoise (Phocoena phocoena) bycatch directly in the turbot gill net fishery in the Black Sea conditions. Sea trials carried out using Dukane NetMark™ 1000 pingers in an active (with pinger) and in a control (without pingers) turbot gill net between March 5 and April 2, 2006 off the Sinop Peninsula. The results showed that Dukane NetMark™1000 pingers have been significantly shown to be effective in reducing P. phocoena bycatch in turbot gill net fisheries without significantly affecting target and non-target fish size and catch. The habituation problem of the species should also be further investigated in the future. © Central Fisheries Research Institute (CFRI) Trabzon, Turkey and Japan International Cooperation Agency (JICA).
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Airguns used in seismic surveys are among the most prevalent and powerful anthropogenic noise sources in marine habitats. They are designed to produce most energy below 100 Hz, but the pulses have also been reported to contain medium-to-high frequency components with the potential to affect small marine mammals, which have their best hearing sensitivity at higher frequencies. In shallow water environments, inhabited by many of such species, the impact of airgun noise may be particularly challenging to assess due to complex propagation conditions. To alleviate the current lack of knowledge on the characteristics and propagation of airgun pulses in shallow water with implications for effects on small marine mammals, we recorded pulses from a single airgun with three operating volumes (10 in<sup>3</sup>, 25 in<sup>3</sup> and 40 in<sup>3</sup>) at six ranges (6, 120, 200, 400, 800 and 1300 m) in a uniform shallow water habitat using two calibrated Reson 4014 hydrophones and four DSG-Ocean acoustic data recorders. We show that airgun pulses in this shallow habitat propagated out to 1300 meters in a way that can be approximated by a 18log(r) geometric transmission loss model, but with a high pass filter effect from the shallow water depth. Source levels were back-calculated to 192 dB re µPa<sup>2</sup>s (sound exposure level) and 200 dB re 1 µPa dB L<sub>eq-fast</sub> (rms over 125 ms duration), and the pulses contained substantial energy up to 10 kHz, even at the furthest recording station at 1300 meters. We conclude that the risk of causing hearing damage when using single airguns in shallow waters is small for both pinnipeds and porpoises. However, there is substantial potential for significant behavioral responses out to several km from the airgun, well beyond the commonly used shut-down zone of 500 meters.
Article
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The marine ecosystem is being increasingly subjected to underwater noise from industrial operations. Our ability to monitor the marine soundscape using passive acoustic technology is important to determine the potential impacts of anthropogenic sound. The objectives of this workshop were to define our current capabilities with regard to passive acoustic monitoring (PAM); to define our current state of knowledge of the marine soundscape, and of underwater noise in particular, and of noise impacts; to identify the needs and concerns of the various stakeholders; and to determine future research and development needs. The workshop was held in Fremantle, Western Australia, on 21 November 2012, the day before the Australian Acoustical Society's annual conference. Three tutorial sessions were presented by leading researchers in the field on underwater acoustic terminology, metrics, the basics of sound propagation, noise modelling and prediction, the marine soundscape (physical ambient, anthropogenic and biological sources), sound recording technology and methods, noise impacts on marine fauna, mitigation and environmental management. Tutorials were followed by rapid-fire presentations of current research associated with the themes of passive acoustic monitoring and noise impact. Discussions pursued on the presented topics, with emphasis on stakeholder needs, prevailing problems, knowledge gaps, potential solutions and future initiatives. The workshop was attended by over 70 participants from within Australia and abroad, hosting a diverse range of expertise and representing the various stakeholders in the marine environment: the offshore oil and gas industry, consulting industry, fishing industry, defence, government (environmental officers, regulators, fisheries officers), environmental groups and academia. The outcomes of the workshop were: . An appreciation of PAM for monitoring of marine fauna, for ecological studies, for measurements of anthropogenic noise, for studying noise impacts and for mitigation monitoring; . A demonstration of the effectiveness of PAM for presence and abundance monitoring (with more acoustic detections than visual in certain circumstances); . An understanding of the limitations of PAM (to vocalising animals) and the potential of combining PAM with visual observations and possibly active acoustic imaging to increase detection probability; . An appreciation of the differences between regulatory approaches in different jurisdictions; . The identification of the need to monitor (and address noise impacts on) entire ecosystems including less iconic (=nonmammalian) species; . The identification of knowledge gaps with regards to unidentified sounds in marine soundscapes, natural variability in soundscapes with space and time necessitating long-term baseline recording, noise impacts on the vast majority of marine species, anthropogenic source signatures and sound transmission.
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Many animals produce louder, longer or more repetitious vocalizations to compensate for increases in environmental noise. Biological costs of increased vocal effort in response to noise, including energetic costs, remain empirically undefined in many taxa, particularly in marine mammals that rely on sound for fundamental biological functions in increasingly noisy habitats. For this investigation, we tested the hypothesis that an increase in vocal effort would result in an energetic cost to the signaler by experimentally measuring oxygen consumption during rest and a two-min vocal period in dolphins that were trained to vary vocal loudness across trials. Vocal effort was quantified as the total acoustic energy of sounds produced. Metabolic rates (MRs) during the vocal period were, on average, 1.2× and 1.5× resting (RMR) in Dolphin A and B, respectively. As vocal effort increased, we found that there was a significant increase in metabolic rate over resting during the 2-min following sound production in both dolphins and in total oxygen consumption (metabolic cost of sound production plus recovery costs) in the dolphin that showed a wider range of vocal effort across trials. Increases in vocal effort, as a consequence of increases in vocal amplitude, repetition rate, and/or duration, are consistent with behavioral responses to noise in free-ranging animals. Here, we empirically demonstrate for the first time in a marine mammal, that these vocal modifications can have an energetic impact at the individual level and importantly, these data provide a mechanistic foundation for evaluating biological consequences of vocal modification in noise-polluted habitats. © 2015. Published by The Company of Biologists Ltd.
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Harbour porpoises Phocoena phocoena are unintentionally caught in gillnets. Although the effectiveness of by-catch mitigation measures has been evaluated many times, only a few studies have investigated the behavioural patterns of the porpoises in relation to the presence of fishing nets. In this study, the reactions of wild harbour porpoises to a modified gillnet were visually observed. The porpoises responded to the net by avoiding it, with reactions being detectable at a distance of >80 m. The number of animals in the pods approaching the net did not affect the behaviour of individuals in relation to the net. These results strongly indicate that porpoises do not usually actively approach gillnets. The by-catch problem seems, therefore, to be caused by individual animals accidentally being caught, likely due to attention shifts or to auditory masking reducing their ability to detect the nets using echolocation.
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The impact of underwater noise on marine life calls for identification of exposure criteria to inform mitigation. Here we review recent experimental evidence with focus on the high-frequency cetaceans and discuss scientifically-based initial exposure criteria. A range of new TTS experiments suggest that harbour and finless porpoises are more sensitive to sound than expected from extrapolations based on results from bottlenose dolphins. Furthermore, the results from TTS experiments and field studies of behavioural reactions to noise, suggest that response thresholds and TTS critically depend on stimulus frequency. Sound exposure levels for pure tones that induce TTS are reasonably consistent at about 100 dB above the hearing threshold for pure tones and sound pressure thresholds for avoidance reactions are in the range of 40-50 dB above the hearing threshold. We propose that frequency weighting with a filter function approximating the inversed audiogram might be appropriate when assessing impact.
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In Denmark, harbour seals, Phoca vitulina, were first protected in 1977, and since then a number of seal reserves have been established in Danish waters. The effectiveness of these reserves to prevent human-induced disturbances to the seal population have, however, not been evaluated.To evaluate this, experimental disturbances were conducted in one of the most important seal reserves in Denmark (Anholt seal reserve). Specifically, the behavioural responses (alert distance, flight initiation distance, flee distances and flight duration) of harbour seals to approaching pedestrians and boats were studied.The project was conducted during three periods related to the breeding cycle of harbour seals. In all periods, harbour seals were alerted by boats at significantly greater distances compared with pedestrians (560–850 m and 200–425 m, respectively). Similar differences in the flight initiation distances were observed, 510–830 m for boats and 165–260 m for pedestrians. In most cases seals were alerted and began to flee when the approaching boat was outside the reserve, whereas seals did not respond to approaching pedestrians until after they had entered the reserve.Harbour seals exhibited weaker and shorter-lasting responses during the breeding season. They were more reluctant to flee and returned to the haul-out site immediately after being disturbed, in some cases even during the disturbance. This seasonal tolerance is most likely attributed to a trade-off between fleeing and nursing during the breeding season, and hence not an indication of habituation.Based on the results of this study it is suggested that the reserve boundaries on land be placed at least 425 m from the haul-out area and the boundary at sea should extend to at least 850 m from the haul-out area in order to secure adequate year-round protection from disturbances. Copyright © 2011 John Wiley & Sons, Ltd.
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Over the last two decades, marine noise pollution has become increasingly recognized as an issue of major significance. The issue has become a primary focus of marine mammal research, but is also of concern to the public and policy makers. The result has been efforts involving a variety of disciplines, and relevant legislation and associated guidance are now in place in many parts of the world. Most current mitigation efforts are directed at reducing the risk of injury from exposure to intense noise, although the effectiveness of such mitigation measures in terms of risk reduction has rarely been quantified. Longer-term chronic impacts of noise including disturbance or masking of sounds critical for feeding and reproduction have received substantially less attention in management. New technologies are being developed for a number of activities which can substantially reduce noise inputs into the marine environment. As with other forms of pollution, reducing input at source is likely to be the most effective way of reducing impacts. We recommend as a priority the implementation of noise quieting technologies and the spatial and temporal exclusion of noise to minimize contact with marine life
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Marine seismic surveys, which use loud, primarily low-frequency sound to penetrate the sea floor, are known to disturb and could harm marine life. The use of these surveys for conventional and alternative offshore energy development as well as research is expanding. Given their proliferation and potential for negative environmental impact, there is a growing need for systematic planning and operational standards to eliminate or at least minimize impacts, especially when surveys occur in sensitive areas. Mitigating immediate impacts is obviously critical, but monitoring for short- as well as long-term effects and impacts is also needed. Regulatory requirements for both mitigation and monitoring vary widely from one country or jurisdiction to another. Historically, most have focused on acute effects but share a common objective of minimizing potential adverse impacts. Herein, we present a comprehensive view of the current state of the art in mitigation and monitoring for seismic surveys. We summarize methods for minimizing and monitoring potential adverse impacts, with required elements in each phase from planning to execution to analysis. Specific examples in different areas are given to illustrate general approaches for predicting, minimizing, and measuring impacts for operations in essentially any marine environment. The critical elements of a robust mitigation and monitoring plan for responsibly conducting marine seismic surveys include obtaining baseline ecological data;substantial advance planning, communication, and critical review; integrated acoustic and visual monitoring during operations; and systematic analysis of results to inform future planning and mitigation.
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Ramp-up or soft-start procedures (i.e., gradual increase in the source level) are used to mitigate the effect of sonar sound on marine mammals, although no one to date has tested whether ramp-up procedures are effective at reducing the effect of sound on marine mammals. We investigated the effectiveness of ramp-up procedures in reducing the area within which changes in hearing thresholds can occur. We modeled the level of sound killer whales (Orcinus orca) were exposed to from a generic sonar operation preceded by different ramp-up schemes. In our model, ramp-up procedures reduced the risk of killer whales receiving sounds of sufficient intensity to affect their hearing. The effectiveness of the ramp-up procedure depended strongly on the assumed response threshold and differed with ramp-up duration, although extending the duration of the ramp up beyond 5 min did not add much to its predicted mitigating effect. The main factors that limited effectiveness of ramp up in a typical antisubmarine warfare scenario were high source level, rapid moving sonar source, and long silences between consecutive sonar transmissions. Our exposure modeling approach can be used to evaluate and optimize mitigation procedures. Modelado de la Efectividad de los Incrementos Graduales en el Nivel de la Fuente para Mitigar Efectos de Sonar sobre Mamíferos Marinos.
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This study describes behavioral changes of wild cetaceans observed during controlled exposures of naval sonar. In 2006 through 2009, 14 experiments were conducted with killer (n = 4), long-finned pilot (n = 6), and sperm (n = 4) whales. A total of 14 6-7 kHz upsweep, 13 1-2 kHz upsweep, and five 1-2 kHz downsweep sonar exposures, as well as seven Silent vessel control exposure sessions and eight playbacks of killer whale sounds were conducted. Sonar signals were transmitted by a towable source that approached each tagged subject from a starting distance of 6 to 8 km with a ramp up of source levels (from 152 to 158 to a maximum of 198 to 214 dB re: 1 mu Pa m). This procedure resulted in a gradual escalation of the sonar received level at the whale, measured by towed hydrophones and by tags that record movement and sound (Dtags). Observers tracked the position of each tagged animal and recorded group-level surface behavior. Two expert panels independently scored the severity of diverse behavioral changes observed during each sonar and control exposure, using the 0 to 9 point severity scale of Southall et al. (2007), and then reached consensus with a third-party moderator. The most severe responses scored (i.e., most likely to affect vital rates) included a temporary separation of a calf from its group, cessation of feeding or resting, and avoidance movements that continued after the sonar stopped transmitting. Higher severity scores were more common during sonar exposure than during Silent control sessions. Scored responses started at lower sound pressure levels (SPLs) for killer whales and were more severe during sonar exposures to killer and sperm whales than to long-finned pilot whales. Exposure sessions with the higher source level of 1 to 2 kHz sonar had more changes and a trend for higher maximum severity than 6 to 7 kHz sessions, but the order of the sessions had no effect. This approach is helpful to standardize the description of behavioral changes that occurred during our experiments and to identify and describe the severity of potential responses of free-ranging cetaceans to sonar.
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Although seal scarers are widely used both to reduce economic losses at fish farms caused by seal predation and to reduce risks posed to marine mammals by offshore pile driving activities, the spatial extent of their deterrent effect on harbour porpoises is still largely unclear. However, this information is crucial to understanding the effects these devices have on the marine environment and to judge their potential as a mitigation measure.A study was conducted in the German North Sea, using passive acoustic monitoring and to some extent simultaneous aerial surveying to specifically study the spatial extent of the deterrence effects of a seal scarer on harbour porpoises. In order to link porpoise detections at various distances to actual sound levels, sound measurements of the seal scarer signal were carried out at several distances from the source.C-POD recordings revealed a significant deterrence effect on harbour porpoises up to 7.5 km away (at about 113 dB re 1 μParms), much further than previously reported. During seal scarer operation the number of porpoise detections within 750 m of the C-PODs decreased by between 52 and 95% of the value before the seal scarer was activated.An aerial survey revealed a significant decrease in porpoise density from 2.4 porpoises km-2 before to 0.3 porpoises km-2 during seal scarer operation within the 990 km2 study area, showing that the decrease in porpoise detections by passive acoustic monitoring was probably indeed the result of a decrease in porpoise abundance.These results may raise serious concerns about unwanted disturbance effects on harbour porpoises in the context of seal scarer use at fish farms and also highlight the need for caution when applied as a mitigation measure during offshore construction.Copyright © 2012 John Wiley & Sons, Ltd.
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There is great interest in exploring and exploiting hydrocarbon resources in the Arctic, and one of the main methods of locating and assessing such resources is seismic survey. Marine seismic surveys involve the use of airguns that introduce high-energy noise to the Arctic’s largely pristine underwater acoustic environment. Narwhals may be particularly sensitive to this noise but so far no studies have addressed the question of direct effects of high-energy airgun pulses on these animals. We are concerned about the possibility that three large recent ice entrapments were causally linked to seismic survey activities. On these occasions narwhals remained in coastal summering areas until well into the fall and early winter season, delaying their annual offshore migration and becoming lethally entrapped by rapidly forming fast ice. About 1000 narwhals died in an ice entrapment in Canada in 2008 and about 100 in two entrapments in Northwest Greenland in 2009–10. We conclude that studies of the direct effects of seismic surveys on narwhals are urgently needed and should ideally precede further seismic surveys in narwhal habitats.
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The surfacing, respiration and diving (SRD) behavior of bowhead whales Balaena mysticetus changes upon exposure to seismic operations. However, it is unknown whether these changes differ by season, reproductive status (calves, mothers, and non-calves), and whale activity (traveling, foraging, or socializing). Such SRD behavioral responses to seismic operations might influence the detectability of whales during aerial surveys. We addressed these questions by applying non-parametric univariate tests and linear mixed models to behavioral data collected by aerial observation of bowheads in the Beaufort Sea from 1980 to 2000. Durations of surfacings decreased upon exposure to seismic operations, especially for traveling or socializing non-calf whales. The mixed models also indicated that dive durations were affected by the presence of seismic operations, but the effects depended on other variables such as season and whale activity. Overall, our results suggest that changes in the behavior exhibited by bowhead whales exposed to seismic operations are context-dependent (i.e. responses to seismic operations depend on both the circumstance and activity of the whale). The level of perceived threat may also be important based on similarities with behavioral changes observed in other air-breathing aquatic foragers facing dangers. We conclude that seismic-induced changes in bowhead SRD behaviors may affect the availability of bowhead whales for visual detection in some circumstances. This in turn means that estimates of abundance and distribution of bowhead whales near seismic surveys should be context-sensitive and incorporate correction factors that account for sound exposure, season, reproductive status, and whale activity.
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Small cetaceans are susceptible to incidental mortality in the various forms of gillnet fisheries throughout their range. Research conducted since 1994 has shown that acoustic alarms (pingers) emitting high-frequency pulsed sounds effectively reduce the number of harbor porpoise Phocoena phocoena casualties in sink gillnets. However, the mechanisms behind the effects of pingers were still not understood. Until now, advantages and risks associated with their widespread use could not be evaluated. Here we present the results of 2 field experiments: (1) theodolite-tracking of harbor porpoises exposed to a single PICE-pinger in Clayoquot Sound, Vancouver Island, Canada and (2) herring Clupea harengus capture rates in surface gillnets equipped with and without acoustic alarms (Dukane Netmark 1000, Lien, PICE) in the Baltic Sea herring fishery at Rugen Island, Germany. Our results show that harbor porpoises do not seem to react to an experimental net in their foraging area (n = 172 groups, median group size = 2 porpoises). Porpoise distance from the mid-point of the net was distributed around a median of only 150 m (range 4 to 987 m). A net equipped with an acoustic alarm, however, was avoided (n = 44 groups) within audible range (distance distribution median = 530 m, range 130 to 1140 m). The porpoises were thus effectively excluded from the ensonified area. Herring, one of the main prey species of harbor porpoises, were not affected by the acoustic alarms tested (n = 25 407 fish captured). The advantages and risks of using acoustic alarms to mitigate by-catch are discussed.
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Estimating the abundance and density of beaked whales is more difficult than for most other cetacean species. Consequently few estimates appear in the published literature. Field identification is problematic, especially for the smaller species, and visual detecti on rates decrease dramatically with Beaufort sea state; prior experience is very important to an observer's ability to detect beaked whales. Passive acoustics may hold future promise for detecting beaked whales from their vocalisations, especially for the larger species. Most published estimates of abundance or density are based on visual line-transect studies that found narrower effective strip widths and lower tracklin e detection probabilities for beaked whales than for most other cetaceans. Published density estimates range from 0.4-44 whales per 1,000km 2 for small beaked whales and up to 68 whales per 1,000km 2 for large beaked whales. Mark-recapture methods based on photo-identification have been used to estimate abundance in a few cases in limited geographical areas. Focused research is needed to improve beaked whale abu ndance and density estimates worldwide.
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1. Owing to the increase of boat-traffic in the ocean many studies have been conducted to determine the response of bottlenose dolphin (Tursiops truncatus) to this kind of disturbance. This species is affected by boats in various ways and the response depends on the behavioural state of the dolphin but also on the kind of vessel. 2. This study aimed to determine the effect of motorboats and trawlers on dolphins' presence, permanence in the area and whistle parameters in Lampedusa waters (Italy). Sampling was carried out between May and December 2006 and between July and September 2009, using experimental passive acoustic monitoring systems (PAM); a total of 300 h of recordings and 3000 whistles were analysed. 3. The dolphins' behavioural strategies depend on the kind of boats: in the case of motorboats, dolphins preferred to leave the area as the disturbance became too heavy to be tolerated; in the case of trawlers, dolphins changed their acoustic behaviour to compensate for the masking noise. 4. The study highlighted the efficacy of PAM to detect the behavioural response of dolphins, suggesting a novel approach to assessing anthropogenic influences on marine mammal vocalizations in the absence of visual observations.
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The concern about the effects of the noise of human activities on marine mammals, particularly whales, has led to a substantial amount of research but there is still much that is not understood, particularly in terms of the behavioural responses to noise and the longer term biological consequences of these responses. There are many challenges in conducting experiments that adequately assess behavioural reactions of whales to noise. These include the need to obtain an adequate sample size with the necessary controls and to measure the range of variables likely to affect the observed response. Analysis is also complex. Well designed experiments are complex and logistically difficult, and thus expensive. This paper discusses the challenges involved and how these are being met in a major series of experiments in Australian waters on the response of humpback whales to the noise of seismic airgun arrays. The project is known as BRAHSS (Behavioural Response of Australian Humpback whales to Seismic Surveys) and aims to provide the information that will allow seismic surveys to be conducted efficiently with minimal impact on whales. It also includes a study of the response to ramp-up in sound level which is widely used at the start of operations, but for which there is little information to show that it is effective. BRAHSS also aims to infer the longer term biological significance of the responses from the results and the knowledge of normal behaviour. The results are expected to have relevance to other sources and species.
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An unprecedented 85 harbour porpoises stranded freshly dead along approximately 100 km of Danish coastline from 7-15 April, 2005. This total is considerably above the mean weekly stranding rate for the whole of Denmark, both for any time of year, 1.23 animals/week (ranging from 0 to 20 during 2003-2008, excluding April 2005), and specifically in April, 0.65 animals/week (0 to 4, same period). Bycatch was established as the cause of death for most of the individuals through typical indications of fisheries interactions, including net markings in the skin and around the flippers, and loss of tail flukes. Local fishermen confirmed unusually large porpoise bycatch in nets set for lumpfish () and the strandings were attributed to an early lumpfish season. However, lumpfish catches for 2005 were not unusual in terms of season onset, peak or total catch, when compared to 2003-2008. Consequently, human activity was combined with environmental factors and the variation in Danish fisheries landings (determined through a principal component analysis) in a two-part statistical model to assess the correlation of these factors with both the presence of fresh strandings and the numbers of strandings on the Danish west coast. The final statistical model (which was forward selected using Akaike information criterion; AIC) indicated that naval presence is correlated with higher rates of porpoise strandings, particularly in combination with certain fisheries, although it is not correlated with the actual presence of strandings. Military vessels from various countries were confirmed in the area from the 7th April, en route to the largest naval exercise in Danish waters to date (Loyal Mariner 2005, 11-28 April). Although sonar usage cannot be confirmed, it is likely that ships were testing various equipment prior to the main exercise. Thus naval activity cannot be ruled out as a possible contributing factor.
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Anthropogenic noise has fundamentally changed the acoustics of terrestrial and aquatic environments, and there is growing empirical evidence that even a single noise exposure can affect behaviour in a variety of vertebrate organisms. Here, we use controlled experiments to investigate how the physiology of a marine invertebrate, the shore crab (Carcinus maenas), is affected by both single and repeated exposure to ship-noise playback. Crabs experiencing ship-noise playback consumed more oxygen, indicating a higher metabolic rate and potentially greater stress, than those exposed to ambient-noise playback. The response to single ship-noise playback was size-dependent, with heavier crabs showing a stronger response than lighter individuals. Repeated exposure to ambient-noise playback led to increased oxygen consumption (probably due to handling stress), whereas repeated exposure to ship-noise playback produced no change in physiological response; explanations include the possibility that crabs exhibited a maximal response on first exposure to ship-noise playback, or that they habituated or become tolerant to it. These results highlight that invertebrates, like vertebrates, may also be susceptible to the detrimental impacts of anthropogenic noise and demonstrate the tractability for more detailed investigations into the effects of this pervasive global pollutant.
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This review highlights significant gaps in our knowledge of the effects of seismic air gun noise on marine mammals. Although the characteristics of the seismic signal at different ranges and depths and at higher frequencies are poorly understood, and there are often insufficient data to identify the appropriate acoustic propagation models to apply in particular conditions, these uncertainties are modest compared with those associated with biological factors. Potential biological effects of air gun noise include physical/physiological effects, behavioral disruption, and indirect effects associated with altered prey availability. Physical/physiological effects could include hearing threshold shifts and auditory damage as well as non-auditory disruption, and can be directly caused by sound exposure or the result of behavioral changes in response to sounds, e.g. recent observations suggesting that exposure to loud noise may result in decompression sickness. Direct information on the extent to which seismic pulses could damage hearing are difficult to obtain and as a consequence the impacts on hearing remain poorly known. Behavioral data have been collected for a few species in a limited range of conditions. Responses, including startle and fright, avoidance, and changes in behavior and vocalization patterns, have been observed in baleen whales, odontocetes, and pinnipeds and in some case these have occurred at ranges of tens or hundreds of kilometers. However, behavioral observations are typically variable, some findings are contradictory, and the biological significance of these effects has not been measured. Where feeding, orientation, hazard avoidance, migration or social behavior are altered, it is possible that populations could be adversely affected. There may also be serious long-term consequences due to chronic exposure, and sound could affect marine mammals indirectly by changing the accessibility of their prey species. A precautionary approach to management and regulation must be recommended. While such large degrees of uncertainty remain, this may result in restrictions to operational practices but these could be relaxed if key uncertainties are clarified by appropriate research.
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This review considers the effect of anthropogenic sound on beaked whales2. Two major conclusions are presented: (1) gas-bubble disease,induced in supersaturated tissue by a behavioural response to acoustic exposure, is a plausible pathologic mechanism for the morbidity andmortality seen in cetaceans associated with sonar exposure and merits further investigation; and (2) current monitoring and mitigationmethods for beaked whales are ineffective for detecting these animals and protecting them from adverse sound exposure. In addition, fourmajor research priorities, needed to address information gaps on the impacts of sound on beaked whales, are identified: (1) controlledexposure experiments to assess beaked whale responses to known sound stimuli; (2) investigation of physiology, anatomy, pathobiologyand behaviour of beaked whales; (3) assessment of baseline diving behaviour and physiology of beaked whales; and (4) a retrospectivereview of beaked whale strandings (16) (PDF) Understanding the impacts of anthropogenic sound on beaked whales.. Available from: https://www.researchgate.net/publication/230737956_Understanding_the_impacts_of_anthropogenic_sound_on_beaked_whales [accessed Mar 31 2020].
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A number of mass strandings of beaked whales have in recent decades been temporally and spatially coincident with military activitiesinvolving the use of midrange sonar. The social behaviour of beaked whales is poorly known, it can be inferred from strandings and someevidence of at-sea sightings. It is believed that some beaked whale species have social organisation at some scale; however most strandingsare of individuals, suggesting that they spend at least some part of their life alone. Thus, the occurrence of unusual mass strandings of beakedwhales is of particular importance. In contrast to some earlier reports, the most deleterious effect that sonar may have on beaked whalesmay not be trauma to the auditory system as a direct result of ensonification. Evidence now suggests that the most serious effect is theevolution of gas bubbles in tissues, driven by behaviourally altered dive profiles (e.g. extended surface intervals) or directly fromensonification. It has been predicted that the tissues of beaked whales are supersaturated with nitrogen gas on ascent due to thecharacteristics of their deep-diving behaviour. The lesions observed in beaked whales that mass stranded in the Canary Islands in 2002 areconsistent with, but not diagnostic of, decompression sickness. These lesions included gas and fat emboli and diffuse multiorganhaemorrhage. This review describes what is known about beaked whale anatomy and physiology and discusses mechanisms that may haveled to beaked whale mass strandings that were induced by anthropogenic sonar. Beaked whale morphology is illustrated using Cuvier’s beaked whale as the subject of the review. As so little is known about the anatomyand physiology of beaked whales, the morphologies of a relatively well-studied delphinid, the bottlenose dolphin and a well-studiedterrestrial mammal, the domestic dog are heavily drawn on. (18) (PDF) Elements of beaked whale anatomy and diving physiology and some hypothetical causes of sonar-related stranding. Available from: https://www.researchgate.net/publication/230737954_Elements_of_beaked_whale_anatomy_and_diving_physiology_and_some_hypothetical_causes_of_sonar-related_stranding [accessed Mar 27 2020].
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Humpback whale (Megaptera novaeangliae) entrapment in nets is a common phenomenon in Newfoundland. In 1991-1992, unusually high entrapment rates were recorded in Trinity Bay on the northeast coast of Newfoundland. The majority of cases occurred in the southern portion of the bay close to Mosquito Cove, a site associated with construction operations (including explosions and drilling) that presumably modified the underwater acoustic environment of lower Trinity Bay. This study reports the findings of the resulting assessment conducted in June 1992 on the impact of the industrial activity on humpback whales foraging in the area. Although explosions were characterized by high-energy signatures with principal energies under 1 kHz, humpback whales showed little behavioral reaction to the detonations in terms of decreased residency, overall movements, or general behavior. However, it appears that the increased entrapment rate may have been influenced by the long-term effects of exposure to deleterious levels of sound.
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The effects of chronic exposure to increasing levels of human-induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human-induced sound on contact-calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (∼10,000 km2) and time period (peak feeding time). We used an array of temporary, bottom-mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel-tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal-to-noise ratio and the assumed recognition differential) for contact-calling right whales was negative (−1 dB) under current ambient noise levels and was further reduced (−2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63–67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10-min period. These results highlight the limitations of exposure-threshold (i.e., dose-response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide-ranging noise effects in emerging ocean-planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. Cuantificación de la Pérdida de Espacio de Comunicación Acústica para Ballenas Francas Dentro y Alrededor de un Santuario Marino Nacional en E. U. A. Los efectos de la exposición crónica a niveles cada vez mayores de ruido submarino inducido por humanos sobre poblaciones de animales marinos dependientes del sonido para comunicarse están poco entendidos. Buscamos desarrollar métodos para cuantificar los efectos del enmascaramiento de la comunicación asociados con sonidos inducidos por humanos sobre el llamado de contacto de ballenas francas (Eubalaena glacialis) en un área ecológicamente relevante (∼ 10,000 km2) y período de tiempo (tiempo pico de alimentación). Utilizamos un conjunto de grabadoras acústicas autónomas, temporales, montadas en el fondo en el Santuario Marino Nacional Banco Stellwagen para monitorear los niveles de sonido ambiental, medir los niveles de sonido asociados con embarcaciones y detectar y localizar llamadas de ballenas. Relacionamos la velocidad del viento, registrada por boyas oceanográficas regionales, con los niveles de sonido ambiental. Utilizamos datos de embarcaciones rastreadoras del Sistema de Identificación Automática para cuantificar las sintonías de embarcaciones comerciales mayores. Con base en estos campos de sonido integrados, la mediana del exceso de señal (la diferencia entre la relación señal-ruido y el diferencial de reconocimiento asumido) para contactar ballenas francas llamadoras fue negativo (−1 dB) bajo niveles de sonido ambiental actuales y disminuyó (−2 dB) con la adición del ruido de los barcos. En comparación con el espacio de comunicación potencial disponible bajo condiciones de ruido históricamente más bajas, las ballenas pueden haber perdido, en promedio 63–67% de su espacio de comunicación. Una o más de las 189 ballenas llamadoras en el área de estudio estuvieron expuestas a niveles de ruido ≥120dB re1μPa de barcos durante 20% del mes, (y un máximo de 11 ballenas estuvo expuesto a ruido en o por arriba de este nivel durante un solo período de 10 minutos. Estos resultados resaltan las limitaciones de las medidas de exposición-umbral (i.e., dosis-respuesta) para evaluar los efectos del ruido antropogénico crónico sobre las oportunidades de comunicación. Nuestros métodos pueden ser utilizados para integrar los efectos de ruido crónico y de amplio rango en los foros emergentes sobre planeación marina que buscan mejorar el manejo de los efectos acumulativos del ruido sobre especies marinas y sus hábitats.
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Many marine mammals communicate by emitting sounds that pass through water. Such sounds can be received across great distances and can influence the behavior of these undersea creatures. In the past few decades, the oceans have become increasingly noisy, as underwater sounds from propellers, sonars, and other human activities make it difficult for marine mammals to communicate. This book discusses, among many other topics, just how well marine mammals hear, how noisy the oceans have become, and what effects these new sounds have on marine mammals. The baseline of ambient noise, the sounds produced by machines and mammals, the sensitivity of marine mammal hearing, and the reactions of marine mammals are also examined. An essential addition to any marine biologists library, Marine Mammals and Noise will be especially appealing to marine mammalogists, researchers, policy makers and regulators, and marine biologists and oceanographers using sound in their research.
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Multiple suppression was carried out on a small scale at the ExxonMobil seismic test pond. Multiple suppression of 8 dB was demonstrated for the bubble curtain alone, and an additional 2 dB was obtained by applying deconvolution on the data recorded with a bubble curtain. Basic data for the design of bubble curtain multiple suppression were obtained in an offshore test with Petroleum Geo-Services. This test established the high reflectivity of a bubble curtain at seismic frequencies. It also confirmed the Woods equation relationship between air volume fraction in seawater and acoustic sound speed in the bubbly mixture, at a point on the curve close to the design operating point.
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The outcome of COP15, the conference on climate change in Copenhagen, was the Copenhagen Accord which was recognised by the 193 countries that attended. The Accord set no compulsory limits on carbon emissions, and none of the countries that introduced it – USA, China, India [with Brazil and South Africa] – has signed the Annexe to the Kyoto Agreement, committing them to limit their emissions. Climate change is only of secondary importance to them compared with eradicating poverty. Nevertheless three of these countries are in the lead currently for installing renewables, far ahead of most of those [only 37 out of 187 countries world-wide] who are committed to limiting their emissions. This paper explains why. The main function of renewable energy is to save fuel, thereby reducing energy imports and maintaining security of energy supplies without the need to fight world wars over them. Also, being capital intensive with all the money paid up-front, renewables avoid the price fluctuations that bedevil the oil and other fossil fuel industries. As capacity is doubling every 3 years, renewables prices will come down with savings of scale, so wind power in particular will soon be the cheapest form of power.
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Mysticete whales produce a wide variety of communication sounds in the very low frequency range (< 100Hz), and existing evidence indicates that their auditory systems are well adapted for hearing low frequency sounds (< 1000Hz). Seismic surveys produce considerable amounts of low-frequency energy, and these sounds can ensonify large portions of the ocean for considerable periods of time. This paper presents some evidence showing that the scales of seismic survey activities (e.g., spatial areas of ecological importance, time periods of biological significance, multiple sources, and multiple years) can expose large portions of populations for considerable periods of time at received levels that could be considered chronic 1 . Presently, the potential impacts from such chronic exposure, either alone or in synergistic combination with other stressors, are not well considered let alone understood. Adequate scientific evidence, both correlational and experimental, is needed to more fully document proximate and cumulative exposure levels and more fully document the types and scales of responses (e.g., behavioral, endocrinological, physiological, neurophysiological) within the proper ecological context. In addition, such empirical and experimental results should be merged with models (e.g., behavioral-population, exposure, risk) to evaluate the potential impacts on individuals and populations, and to build realistic and effective mechanisms for regulating, mitigating and monitoring impacts beyond the relatively short-term, small-scale perspectives usually considered. It is appreciated that considerations of such potential impacts over ecologically realistic scales represent a significant challenge, and solutions will require creative changes in attitude, technology and scientific activism. That said, these are the scales over which impacts must be address to achieve effective, long-term solutions of benefit to marine environments and whale populations. Brief Background There is considerable evidence describing the sounds produced by mysticetes (Edds-Walton 1997, Thompson et al. 1979). All species for which modest acoustic recordings exist (i.e., all but pygmy right and sei whales) are known to produce sounds in the 40 – 1000 Hz range. Typically, sounds are partitioned into transient calls and hierarchically organized sound patterns, referred to as songs. Balaenids also produce an intense, broadband, short duration sound referred to as a "gunshot" (Parks et al. 2005.) Playback experiments 2 have demonstrated that both calls and songs function for communication between conspecifics (Clark and Clark 1980, Tyack 1983, Mobley et al. 1988, Gademke et al. 2004, Parks 2003.) Most sounds are low-frequency (< 1000 Hz) and many have considerable energy in the very low (< 100 Hz) or infrasonic (ca, < 20-25 Hz) frequency bands.
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Ocean noise pollution is of special concern for cetaceans, as they are highly dependent on sound as their principal sense. Sound travels very efficiently underwater, so the potential area impacted can be thousands of square kilometres or more. The principal anthropogenic noise sources are underwater explosions (nuclear and otherwise), shipping, seismic exploration by mainly the oil and gas industries, and naval sonar operations. Strandings and mortalities of especially beaked whales (family Ziphiidae) have in many cases been conclusively linked to noise events such as naval maneuvers involving tactical sonars or seismic surveys, though other cetacean species may also be involved. The mechanisms behind this mortality are still unknown, but are most likely related to gas and fat emboli at least partially mediated by a behavioral response, such as a change in diving pattern. Estimated received sound levels in these events are typically not high enough to cause hearing damage, implying that the auditory system may not always be the best indicator for noise impacts. Beaked whales are found in small, possibly genetically isolated, local populations that are resident year-round. Thus, even transient and localized acoustic impacts can have prolonged and serious population consequences, as may have occurred following at least one stranding. Populations may also be threatened by noise through reactions such as increased stress levels, abandonment of important habitat, and "masking" or the obscuring of natural sounds. Documented changes in vocal behavior may lead to reductions in foraging efficiency or mating opportunities. Responses are highly variable between species, age classes, behavioral states, etc., making extrapolations problematic. Also, short-term responses may not be good proxies of long-term population-level impacts. There are many examples of apparent tolerance of noise by cetaceans, however. Noise can also affect cetaceans indirectly through their prey. Fish show permanent and temporary hearing loss, reduced catch rates, stress, and behavioral reactions to noise. Management implications of noise impacts include difficulties in establishing "safe" exposure levels, shortcomings of some mitigation tools, the need for precaution in the form of reducing noise levels and distancing noise from biologically important areas, and the role of marine protected areas and monitoring in safeguarding cetaceans especially from cumulative and synergistic effects.
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Acoustic masking from anthropogenic noise is increasingly being considered as a threat to marine mammals, particularly low-frequency specialists such as baleen whales. Low-frequency ocean noise has increased in recent decades, often in habitats with seasonally resident populations of marine mammals, raising concerns that noise chronically influences life histories of individuals and populations. In contrast to physical harm from intense anthropogenic sources, which can have acute impacts on individuals, masking from chronic noise sources has been difficult to quantify at individ- ual or population levels, and resulting effects have been even more difficult to assess. This paper pre- sents an analytical paradigm to quantify changes in an animal's acoustic communication space as a result of spatial, spectral, and temporal changes in background noise, providing a functional defini- tion of communication masking for free-ranging animals and a metric to quantify the potential for communication masking. We use the sonar equation, a combination of modeling and analytical tech- niques, and measurements from empirical data to calculate time-varying spatial maps of potential communication space for singing fin (Balaenoptera physalus), singing humpback (Megoptera novaeangliae), and calling right (Eubalaena glacialis) whales. These illustrate how the measured loss of communication space as a result of differing levels of noise is converted into a time-varying mea- sure of communication masking. The proposed paradigm and mechanisms for measuring levels of communication masking can be applied to different species, contexts, acoustic habitats and ocean noise scenes to estimate the potential impacts of masking at the individual and population levels.