High-frequency hearing in seals and sea lions

Cunningham, Kane A.; Reichmuth, Colleen

doi:10.1016/j.heares.2015.10.002

Cited by 31 publications

(46 citation statements)

References 25 publications

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“…Therefore, there is clear potential that the acoustic signals produced by some sonar systems could elicit behavioural responses in these species (Hastie, Donovan, Götz, & Janik, ). However, the fundamental frequency of the sonar used in the current study (720 kHz) was well above the effective hearing range of harbour seals (Cunningham & Reichmuth, ), and recordings indicate that low‐frequency components of the signal are relatively low in amplitude (Hastie, ); this suggests that the risk of this sonar system eliciting behavioural responses by harbour seals is relatively small.…”

Section: Discussionmentioning

confidence: 71%

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

Hastie

Bivins

Coram

et al. 2019

Aquatic Conservation

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Understanding how marine predators utilize habitats requires that we consider their behaviour in three dimensions. Recent research has shown that marine mammals often make use of tidally energetic locations for foraging, yet data are generally limited to observations of animals at the water surface. Such areas are also of interest to the renewable energy industry for the deployment of tidal‐stream energy turbines; this has led to concerns about potential impacts on marine mammals. Methods for measuring animal movements underwater are limited; however, active sonar can image marine mammals and could potentially measure three‐dimensional movements in tidally energetic locations. Here, a dual 720 kHz sonar system was developed to investigate the three‐dimensional movements of harbour seals (Phoca vitulina) in a tidally energetic channel. Estimated mean depth (distance from the surface) of seals was 12.0 m (95% confidence intervals [CIs]: 11.6–12.4 m), and the majority of time was spent at the surface and at approximately 10–12 m distance from the surface. When expressed as distances from the sea bed, mean distance was 18.5 m (95% CI: 18.0–18.9 m), and the majority of time was spent at 14 m from the sea bed. Seal movements were generally in the same direction as the tidal flow with mean horizontal speeds of between 0.51 and 3.13 m s−1 (95% CIs = 1.24–1.54 m s−1). Mean vertical velocities (where negative and positive values represent a descent and ascent respectively) for each seal track ranged between −1.76 and +0.88 m s−1 (95% CIs: −0.23 to +0.03 m s−1). These results provide a basis for understanding how seals utilize a dynamic tidal environment and suggest that harbour seal behaviour can be markedly different to less tidally energetic habitats. The results also have important implications for the prediction of risk associated with interactions between diving seals and tidal turbines in these dynamic habitats.

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Section: Discussionmentioning

confidence: 71%

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

Hastie

Bivins

Coram

et al. 2019

Aquatic Conservation

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“…Audiograms reported by Kastak and Schusterman (), Hemilä et al . (), and Cunningham and Reichmuth () in NES and other phocid seals present with an abrupt curve into high‐frequency range starting roughly at 50 kHz. Such results strongly match with our mathematical simulation where markedly increased displacement of stapes footplate occurs at the same frequency.…”

Section: Discussionmentioning

confidence: 90%

A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal (Mirounga angustirostris) Ear Anatomy and Histology

Smodlaka

Khamas

Jungers

et al. 2018

The Anatomical Record

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The most conspicuous aural adaptation in northern elephant seals (NES) is complete absence of an auricle and a tortuous collapsed external acoustic meatus. The NES epitympanic recess contains massive ossicles immersed in the middle ear cavernous sinuses. Engorgement of the cavernous sinuses would make ossicles fully buoyant during deep diving. NES have a comparatively larger cochlear nerve, which carries a significantly larger number of axons than in terrestrial mammals, which would give them auditory ability similar to the obligate marine mammals such as cetaceans. Our calculations show that the traditional "air-dependent" impedance matching mechanism in NES functions to just half of the capacity compared with the one described in terrestrial mammals. Impedance matching would be further hindered in NES while diving due to fully collapsed external acoustic meatus. Thanks to similarities of acoustic impedance between the sea water, soft tissues, and blood sinuses, very little sound energy would be reflected and lost. When sound is generated underwater, the large ossicles, buoyant in the cavernous sinus, would not move due to oscillation of tympanic membrane. Rather, they would be oscillating due to their inertia and process of acoustic streaming. Our mathematical simulation shows that an increase in sound frequency would cause increased displacement of the stapedial footplate and thus transmit the sound energy to the inner ear. We contend that during diving, impedance matching and sound signal amplification in the middle ear courses through

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“…While many recent studies have sought to address the effects of underwater noise on cetaceans (Nowacek, Thorne, Johnston, & Tyack, 2007), comparatively less is known about exposure and reactions to noise in pinnipeds while at sea. Like cetaceans, pinnipeds have sensitive underwater hearing; their full hearing range extends from a few hundred Hz to 70-80 kHz (Cunningham & Reichmuth, 2016;Hemilä, Nummela, Berta, & Reuter, 2006). They rely on sound for communication (Mathevon, Casey, Reichmuth, & Charrier, 2017;Van Parijs, Hastie, & Thompson, 1999), predator detection (Deecke, Slater, & Ford, 2002), and possibly also for navigation and listening for prey (Schusterman, Levenson, Reichmuth, & Southall, 2000).…”

Section: Introductionmentioning

confidence: 99%

Long‐term sound and movement recording tags to study natural behavior and reaction to ship noise of seals

Mikkelsen

Johnson

Wisniewska

et al. 2019

Ecology and Evolution

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The impact of anthropogenic noise on marine fauna is of increasing conservation concern with vessel noise being one of the major contributors. Animals that rely on shallow coastal habitats may be especially vulnerable to this form of pollution. Very limited information is available on how much noise from ship traffic individual animals experience, and how they may react to it due to a lack of suitable methods. To address this, we developed long‐duration audio and 3D‐movement tags (DTAGs) and deployed them on three harbor seals and two gray seals in the North Sea during 2015–2016. These tags recorded sound, accelerometry, magnetometry, and pressure continuously for up to 21 days. GPS positions were also sampled for one seal continuously throughout the recording period. A separate tag, combining a camera and an accelerometer logger, was deployed on two harbor seals to visualize specific behaviors that helped interpret accelerometer signals in the DTAG data. Combining data from depth, accelerometer, and audio sensors, we found that animals spent 6.6%–42.3% of the time hauled out (either on land or partly submerged), and 5.3%–12.4% of their at‐sea time resting at the sea bottom, while the remaining time was used for traveling, resting at surface, and foraging. Animals were exposed to audible vessel noise 2.2%–20.5% of their time when in water, and we demonstrate that interruption of functional behaviors (e.g., resting) in some cases coincides with high‐level vessel noise. Two‐thirds of the ship noise events were traceable by the AIS vessel tracking system, while one‐third comprised vessels without AIS. This preliminary study demonstrates how concomitant long‐term continuous broadband on‐animal sound and movement recordings may be an important tool in future quantification of disturbance effects of anthropogenic activities at sea and assessment of long‐term population impacts on pinnipeds.

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High-frequency hearing in seals and sea lions

Cited by 31 publications

References 25 publications

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

A Novel Understanding of Phocidae Hearing Adaptations Through a Study of Northern Elephant Seal (Mirounga angustirostris) Ear Anatomy and Histology

Long‐term sound and movement recording tags to study natural behavior and reaction to ship noise of seals

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