The Rate with which a Harbor Porpoise Uses Echolocation at Night

Akamatsu, Tomonari; Hatakeyama, Yoshimi; Kojima, Takeo; Soeda, Hideo

doi:10.1007/978-1-4615-3406-8_22

Cited by 10 publications

(12 citation statements)

References 6 publications

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“…Dolphin may have co-processed acoustic and visual information and integrated them in real time [ 53 ]. This was further supported by the observations that the active echolocation activity of harbor porpoise increased when ambient lighting was abruptly decreased [ 54 ].…”

Section: Discussionmentioning

confidence: 52%

Passive Acoustic Monitoring the Diel, Lunar, Seasonal and Tidal Patterns in the Biosonar Activity of the Indo-Pacific Humpback Dolphins (Sousa chinensis) in the Pearl River Estuary, China

et al. 2015

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A growing demand for sustainable energy has led to an increase in construction of offshore windfarms. Guishan windmill farm will be constructed in the Pearl River Estuary, China, which sustains the world’s largest known population of Indo-Pacific humpback dolphins (Sousa chinensis). Dolphin conservation is an urgent issue in this region. By using passive acoustic monitoring, a baseline distribution of data on this species in the Pearl River Estuary during pre-construction period had been collected. Dolphin biosonar detection and its diel, lunar, seasonal and tidal patterns were examined using a Generalized Linear Model. Significant higher echolocation detections at night than during the day, in winter-spring than in summer-autumn, at high tide than at flood tide were recognized. Significant higher echolocation detections during the new moon were recognized at night time. The diel, lunar and seasonal patterns for the echolocation encounter duration also significantly varied. These patterns could be due to the spatial-temporal variability of dolphin prey and illumination conditions. The baseline information will be useful for driving further effective action on the conservation of this species and in facilitating later assessments of the effects of the offshore windfarm on the dolphins by comparing the baseline to post construction and post mitigation efforts.

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Section: Discussionmentioning

confidence: 52%

Passive Acoustic Monitoring the Diel, Lunar, Seasonal and Tidal Patterns in the Biosonar Activity of the Indo-Pacific Humpback Dolphins (Sousa chinensis) in the Pearl River Estuary, China

et al. 2015

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“…The deepest recorded dives were equal to the maximum water depth in both areas, about 230 and 90 m, respectively. During darkness, one captive bottlenose dolphin (Akamatsu et al 1995) and one captive harbor porpoise (Akamatsu et al 1992) increased the number of echolocation trains emitted per unit time. Yet another study did not find any increase in the total train rate of two harbor porpoises during darkness (Kastelein et a/.…”

Section: Discussionmentioning

confidence: 99%

“…The number of echolocation trains per minute varies from one to 13 for captive harbor porpoises. Individual differences, as well as an increased rate during darkness, have been reported (Akamatsu et al 1992(Akamatsu et al , 1994Kastelein et al 1995a).…”

mentioning

confidence: 84%

Diel Variation in Echolocation Behavior of Wild Harbor Porpoises

2005

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The echolocation rate and behavior of wild harbor porpoises were studied using a harbor porpoise click detector (POD) deployed close to the bottom at 40 m depth in Scottish waters, UK, April—June 2001. Echolocation variables were compared among four diel phases; morning, day, evening, and night. The echolocation encounter rate, the minimum interclick interval per train, and the proportion of echolocation click trains with a minimum interclick interval below 10 msec were all significantly higher at night than during the day. The variation in echolocation rate implies that porpoises increased their echolocation rate and/or visited the depth of the POD more often at night than during the day. Further, the changes in minimum interclick interval per train suggest that they used their echolocation for foraging or investigating objects at a close range to a higher extent, and acoustically explored the environment at greater distances at night than during the day.

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“…The click-light (Akamatsu et al 1992) was activated as it detected each echolocation signal picked up by a hydrophone set on the melon of each porpoise (Fig. 2).…”

Section: Methodsmentioning

confidence: 99%

“…To monitor echolocation rates, we developed a similar system, referred to as the "click-light" that permits visual detection of high-frequency pulse signals (Akamatsu et al 1992). The click-light enabled us to observe the echolocation rate of two harbor porpoises (Phocoena phocoena) during the night over a twoweek period.…”

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confidence: 99%

ECHOLOCATION RATES OF TWO HARBOR PORPOISES (PHOCOENA PHOCOENA)

Akamatsu

Hatakeyama

Kojima

et al. 1994

Marine Mammal Science

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The rate of occurrence of click trains of two harbor porpoises (Phocoena phocoena) were counted during 14 nights. We developed an echolocation signal detection system that was harnessed to a porpoise and activated a light when the animal emitted an echolocation signal. This device, referred to as a click‐light, detects echolocation signals above 150 dB re 1 μPa in the 28–180 kHz range. Echolocation rates, i.e., occurrences of click trains, changed frequently, ranging from 0 to 25 per minute. Echolocation rates were affected by feeding, individual difference, and enclosure type such as the net enclosure and the pool. The porpoise echolocation rates seemed to show acclimation.

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The Rate with which a Harbor Porpoise Uses Echolocation at Night

Cited by 10 publications

References 6 publications

Passive Acoustic Monitoring the Diel, Lunar, Seasonal and Tidal Patterns in the Biosonar Activity of the Indo-Pacific Humpback Dolphins (Sousa chinensis) in the Pearl River Estuary, China

Passive Acoustic Monitoring the Diel, Lunar, Seasonal and Tidal Patterns in the Biosonar Activity of the Indo-Pacific Humpback Dolphins (Sousa chinensis) in the Pearl River Estuary, China

Diel Variation in Echolocation Behavior of Wild Harbor Porpoises

ECHOLOCATION RATES OF TWO HARBOR PORPOISES (PHOCOENA PHOCOENA)

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