A vessel noise budget for Admiralty Inlet, Puget Sound, Washington (USA)

Bassett, Christopher; Polagye, Brian; Holt, Marla M.; Thomson, Jim

doi:10.1121/1.4763548

Cited by 48 publications

(57 citation statements)

References 28 publications

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“…However, our results show that contribution of local boat noise to background noise levels ranged from 16-19 dB, depending on the study area, and on average was nearly 10 dB higher than wind contribution. This value is similar to those described in the literature where it is documented that below 1 kHz ship traffic regularly increases noise levels by 25 dB above background levels (Bassett et al, 2012). These increases in ambient noise might be sufficient to mask baleen whale calls unless they are able to compensate vocally, which is known as the Lombard effect (Lombard, 1911).…”

Section: Discussionsupporting

confidence: 72%

Underwater Ambient Noise in a Baleen Whale Migratory Habitat Off the Azores

et al. 2017

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Assessment of underwater noise is of particular interest given the increase in noise-generating human activities and the potential negative effects on marine mammals which depend on sound for many vital processes. The Azores archipelago is an important migratory and feeding habitat for blue (Balaenoptera musculus), fin (Balaenoptera physalus) and sei whales (Balaenoptera borealis) en route to summering grounds in northern Atlantic waters. High levels of low frequency noise in this area could displace whales or interfere with foraging behavior, impacting energy intake during a critical stage of their annual cycle. In this study, bottom-mounted Ecological Acoustic Recorders were deployed at three Azorean seamounts (Condor, Açores, and Gigante) to measure temporal variations in background noise levels and ship noise in the 18-1,000 Hz frequency band, used by baleen whales to emit and receive sounds. Monthly average noise levels ranged from 90.3 dB re 1 µPa (Açores seamount) to 103.1 dB re 1 µPa (Condor seamount) and local ship noise was present up to 13% of the recording time in Condor. At this location, average contribution of local boat noise to background noise levels is almost 10 dB higher than wind contribution, which might temporally affect detection ranges for baleen whale calls and difficult communication at long ranges. Given the low time percentatge with noise levels above 120 dB re 1 µPa found here (3.3% at Condor), we woud expect limited behavioral responses to ships from baleen whales. Sound pressure levels measured in the Azores are lower than those reported for the Mediterranean basin and the Strait of Gibraltar. However, the currently unknown effects of baleen whale vocalization masking and the increasing presence of boats at the monitored sites underline the need for continuous monitoring to understand any long-term impacts on whales.

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Section: Discussionsupporting

confidence: 72%

Underwater Ambient Noise in a Baleen Whale Migratory Habitat Off the Azores

et al. 2017

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“…Nonetheless, in coastal habitats near major ports, vessel transits typically occur many times per day, resulting in a high percentage of time that vessels increase ambient noise levels (Bassett et al, 2012;Erbe et al, 2012). Even modest metabolic costs of modified vocal behavior in chronically noisy habitats could have negative effects on certain individuals, particularly those who fail to meet their daily energy requirements during energetically vulnerable periods such as reproduction and lactation.…”

Section: Discussionmentioning

confidence: 99%

“…Chronic sources of anthropogenic noise, such as those associated with vessel traffic near major urban ports (Bassett et al, 2012;Erbe et al, 2012), are particularly concerning given repeated exposure to local populations. Vocal responses to noise are well documented in many whale and dolphin species, including increases in whistle repetition rate in bottlenose dolphins during boat approaches (Tursiops truncatus; Buckstaff, 2004) and increases in call amplitude as noise levels increase in endangered killer whales (Orcinus orca; Holt et al, 2009) and North Atlantic right whales (Eubalaena glacialis; Parks et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Vocal performance affects metabolic rate in dolphins: implications for animals communicating in noisy environments

Holt

Noren

Dunkin

et al. 2015

Journal of Experimental Biology

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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 2 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 during the vocal period were, on average, 1.2 and 1.5 times resting metabolic rate (RMR) in dolphin A and B, respectively. As vocal effort increased, we found that there was a significant increase in metabolic rate over RMR 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.

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“…If all vessels changed their minimum approach distance from 100 to 200 yd (91 to 183 m), on average, then the expected noise reduction would be in the range of 3 to 6 dB, assuming cylindrical or spherical spreading loss (10 to 20 × log distance). This is likely an oversimplified assumption, as there are many other variables that contribute to the amount of noise radiated by vessels, such as vessel type, size, propulsion system, operational speed, and number of propellers (Holt et al 2009, Bassett et al 2012, McKenna et al 2013, Houghton et al 2015, Veirs et al 2016. Indeed, differences in noise levels were not explained by the implementation of vessel regulations or vessel distance.…”

Section: Discussionmentioning

confidence: 99%

“…This population is avidly observed by local whalewatching vessels, especially during summer daylight hours. In addition, commercial shipping, fishing, passenger, and recreational vessels frequently transit their summer/fall feeding grounds (Bassett et al 2012, Veirs et al 2016. Vessel counts collected within 0.5 mile (0.8 km) of these killer whales average around 15 to 20 vessels but can reach up to 80 vessels or more during peak summer periods (Seely 2015).…”

Section: Introductionmentioning

confidence: 99%

Noise levels received by endangered killer whales Orcinus orca before and after implementation of vessel regulations

Holt¹,

Hanson²,

Giles³

et al. 2017

Endang. Species. Res.

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Whale watching is often conducted from motorized vessels, which contribute to underwater noise pollution and can disturb marine mammals. Protective measures can ameliorate some effects of disturbance, but it is crucial to empirically assess the effectiveness of such measures, particularly for endangered species. We quantitatively compared noise exposure to endangered southern resident killer whales before and after US federal vessel regulations were established to protect this population from disturbance by vessels and sound. We expected to see a reduction in noise exposure to this population from vessel sound propagation loss due to a doubling of the minimum viewing distance relative to a prior state law. Noise levels were empirically measured from digital acoustic recording tags (DTAGs) suction-cup attached to killer whales in transboundary critical habitat. We collected concurrent vessel data during DTAG deployments to relate to received noise levels at the animal. Results of a linear mixed model analysis that included 10 explanatory variables in candidate models revealed that noise was best predicted by animal ID, vessel count, vessel speed category, and year. Vessel count and speed category were positive predictors of noise levels. Vessel regulations (before vs. after implementation), country, and average vessel distance were not significant predictors of noise levels, although only 1 yr of baseline data limited assessment. These findings inform managers about the effectiveness of current regulations for viewing killer whales and are applicable to other cetacean species that are exposed to vessel noise from whale-watching activities.

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A vessel noise budget for Admiralty Inlet, Puget Sound, Washington (USA)

Cited by 48 publications

References 28 publications

Underwater Ambient Noise in a Baleen Whale Migratory Habitat Off the Azores

Underwater Ambient Noise in a Baleen Whale Migratory Habitat Off the Azores

Vocal performance affects metabolic rate in dolphins: implications for animals communicating in noisy environments

Noise levels received by endangered killer whales Orcinus orca before and after implementation of vessel regulations

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