What question did this study set out to answer?

To determine whether migrating bowhead whales pass census stations beyond visual observation range and evaluate the utility of passive acoustic monitoring for population counts.

October 1, 1985The Journal of the Acoustical Society of AmericaOpen Access

Passive acoustic location of bowhead whales in a population census off Point Barrow, Alaska

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Authors

WCWilliam C. CummingsUniversity of Miami DHD. V. HollidayScripps Institution of Oceanography

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Implication

Acoustic tracking study demonstrates significant offshore migration beyond visual range in bowhead whales, indicating visual censuses alone substantially underestimate population size.

Key Points

To determine whether migrating bowhead whales pass census stations beyond visual observation range and evaluate the utility of passive acoustic monitoring for population counts.
Deployed a sonobuoy array in a nearshore sea lead to passively locate bowhead vocalizations over 120-degree sectors spanning up to 10 km.
Tracked acoustic bearing and range for 182 whale sounds over 48 hours and 37 sounds over 15 hours, comparing acoustic locations to visual census observations of 242 whales.
Sixty-eight percent of 182 localized sounds originated beyond 2 km (closest point of approach), where only 1% of 242 whales were visually sighted, and 53% originated beyond 3 km, where zero whales were sighted.
Whale vocalizations reached peak spectrum source levels up to 189 dB re: 1 microPa at 1 m, with two tracked individuals traveling at mean speeds of 1.5 and 1.8 knots.
A lack of correlation between acoustic detections and visual sightings precluded using vocalization counts directly to tally individuals or derive unseen-to-observed ratios.

Cite This Study

Cummings et al. (1985) studied this question.

synapsesocial.com/papers/6a75fd24b59e1a4df6786742 https://doi.org/10.1121/1.392933

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Implication

Acoustic tracking study demonstrates significant offshore migration beyond visual range in bowhead whales, indicating visual censuses alone substantially underestimate population size.

Passive acoustic location of bowhead whales in a population census off Point Barrow, Alaska

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Member takes

Implication

Key Points

Cite This Study

Passive acoustic location of bowhead whales in a population census off Point Barrow, Alaska

Discussion

Member takes

Implication

Key Points

Cite This Study

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