What is the reason that the circle never becomes infinite?

The reason P never becomes infinite is that noise contributions from singers at the edge of the circle contribute less and less to the sound field as the radius of the circle increases, despite the fact that the number of noise sources increases linearly with range.

What is the advantage of using nightly peaks?

An advantage to using nightly peaks (instead of daytime levels) is that it avoids contamination from boat engines since vessel activity is very low, and likely nonexistent, between dusk and dawn.

What is the sensitivity of ambient noise levels to changes in the singers’ relative population size?

Given an acoustic propagation environment, and assuming various parameters about humpback whale singing behavior, the model predicts (1) ambient noise levels as a function of frequency and singer population size and (2) the “sensitivity” of ambient noise levels to changes in the singers’ relative population size.

What is the effect of the spatial density of the singers?

That is, the spatial density of the singers does not change, but the region occupied by singers expands and contracts with respective increases and decreases in the number of singers present.

What is the reason for using dB units to describe ambient noise levels?

The choice of 10log10N (i.e., dB “whales re 1 whale”) as a measure of population change is convenient since the authors are using dB units to describe ambient noise levels.

What is the main reason why the humpback whales are not a good candidate?

Depending upon the season, blue, pygmy blue, and fin whales may be good future candidates for testing and applying these models (McDonald and Fox, 1999; Gavrilov and McCauley, 2013) and would be valuable for reserve management personnel or scientists who are interested in quantifying a general increase or decrease in the relative abundance of animals.

What is the trend of humpback whale density?

From past visual survey research, it is known that humpback whale density tends to increase eastward from Punta Gorda to Cabo Pulmo (Jim enez-L opez, 2006).

Open AccessJournal Article10.1121/1.4962217

Humpback whale-generated ambient noise levels provide insight into singers' spatial densities

Kerri D. Seger, +5 more

- 08 Sep 2016

- Journal of the Acoustical Society of Ame...

- Vol. 140, Iss: 3, pp 1581-1597

TL;DR: This theoretical model predicts that changes in ambient noise levels with respect to fractional changes in singer population (defined as the noise "sensitivity") are relatively unaffected by the source level distributions and song spectra of individual humpback whales (Megaptera novaeangliae).

Abstract: Baleen whale vocal activity can be the dominant underwater ambient noise source for certain locations and seasons. Previous wind-driven ambient-noise formulations have been adjusted to model ambient noise levels generated by random distributions of singing humpback whales in ocean waveguides and have been combined to a single model. This theoretical model predicts that changes in ambient noise levels with respect to fractional changes in singer population (defined as the noise “sensitivity”) are relatively unaffected by the source level distributions and song spectra of individual humpback whales (Megaptera novaeangliae). However, the noise “sensitivity” does depend on frequency and on how the singers' spatial density changes with population size. The theoretical model was tested by comparing visual line transect surveys with bottom-mounted passive acoustic data collected during the 2013 and 2014 humpback whale breeding seasons off Los Cabos, Mexico. A generalized linear model (GLM) estimated the noise “s...

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Most frequently asked questions

1. What are the contributions in "Humpback whale-generated ambient noise levels provide insight into singers' spatial densities" ?

Seger et al. this paper used waveguide models to estimate the expected d value for an area with known bathymetry and sound speed profile, and then compared it to a GLM using empirical data so d could be appropriately adjusted and interpreted.

2. What are the only unknown parameters in Eq. (3)?

Since propagation parameters can be estimated with knowledge about the ocean floor’s geology and the sound speed profile measurements, the only remaining unknown parameters in Eq. (3) include those describing how the species in question is spatially distributed.

3. What can be used to estimate d?

Since only relative population changes need to be measured [as d(logN)¼ dN/N], a small line transect survey can be used to estimate d as long as the following criteria are met.

4. What was the way to count whales?

only male whales should be counted, since only males sing, but since whales could not be sexed, all three options could easily include females.

FIG. 7. (Color online) (a) Plots of the 10th, median, and 90th percentiles of the noise intensity computed between 300 and 350 Hz for every hour across the entire 2013 recording season at Cerros Colorados. (b) An expansion of time scale in (a) to show nine days in detail. A diel cycle is clearly visible, with a peak:trough dynamic range of 10–15 dB.

FIG. 4. (Color online) Model of humpback whale ambient noise intensity generated over 50 Hz bandwidths, as a function of singing region radius R, using parameters identical to Fig. 3. Values of an “empirical” dCD are shown, estimated by a linear fit (dashed line) between 2 and 20 km, and then using Eq. (5b). Center frequencies of the bandwidth samples are (a) 125 Hz, (b) 325 Hz, (c) 525 Hz, (d) 725 Hz, and (e) 925 Hz. Subplot (f) shows a noise estimate integrated between 100 and 1000 Hz and assumes a flat song spectrum.

FIG. 3. (Color online) (a) Modeled ambient noise power spectral density (in units of dB re 1 lPa2/Hz) generated from singing humpback whales in an ocean environment representative of Los Cabos, Mexico, as detected by a recorder deployed 80 m deep in a 90 m deep waveguide. The noise is displayed as a function of frequency and the radius R of the singing region. The power spectral density of the whale song was assumed to be a constant value of 125 dB re 1 lPa2/ Hz between 100 and 1000 Hz (total source intensity of 155 dB re 1 lPa). No additional ambient noise sources are included in the model, so the low levels shown for high frequencies and small values of R may be masked by other ambient noise sources in a real environment. (b) Modeled noise sensitivity d as a function of frequency and regional radius R for a CD case, computed from Eq. (5b) and (A6), and neglecting Qindiv. The sensitivity is a unitless value that can range from 0 to over 1.

FIG. 6. (Color online) The five sound metrics used were the hourly average of the 50th percentile of the sound level at (A) the peak hour the night before a survey, (B) the peak hour the night after a survey, (C) the hour concurrent with a visual survey, (D) the mean of the peaks from the nights before and after a survey, and (E) the mean of the maximum dB variation of the nights before and after a survey.

FIG. 10. (Color online) The observed values (open circles) of d for nine different bandwidths and their standard errors (starred lines) compared with theoretical values (solid and dashed curves) for a constant-density scenario. The dashed curve represents the sensitivity evaluated at a fixed singing radius of 20 km. The solid curve reproduces the values of d obtained from the slopes of the dashed lines shown in Fig. 4, which effectively estimates the average sensitivity measured from a population of singers that expands its region from 2 to 20 km between measurement periods. Observed values are obtained directly from the GLM using all counted whales and acoustic metric D. The solid box represents theoretically permissible values of d for a constant-density model, where Qindiv¼ 0. A constant area scenario would yield values of 1 or larger.

FIG. 1. (Color online) Ambient “noise” generated from humpback whale song varies throughout the day. Two 60-s spectrograms illustrate times of relatively low (top) and high (bottom) singing activity at Cerros Colorados in 2014 as recorded on an autonomous bottommounted hydrophone.

Citations

An update to the methods in Endangered Species Research 2011 paper "Estimating North Pacific right whale Eubalaena japonica density using passive acoustic cue counting"

Tiago Reis Marques, +4 more

- 01 Jan 2012

TL;DR: In this paper, the authors presented a method for estimating animal density from fixed passive acoustic detec- tors, and illustrate it by estimating the density of North Pacific right whales Eubalaena japonica in the areas surrounding 3 hydrophones deployed in the southeastern Bering Sea in 2001 to 2002 and 2005 to 2006.

...read moreread less

•Journal Article•10.3354/ESR01080

Fluctuations in Hawaii’s humpback whale Megaptera novaeangliae population inferred from male song chorusing off Maui

Anke Kügler, +5 more

- 17 Dec 2020

- Endangered Species Research

TL;DR: In this paper, the authors examined song chorusing recorded through long-term passive acoustic monitoring at 6 sites off Maui as a proxy for relative whale abundance between 2014 and 2019.

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•Journal Article•10.3389/FPSYG.2018.01156

The Sonar Model for Humpback Whale Song Revised.

Eduardo Mercado

- 16 Jul 2018

- Frontiers in Psychology

TL;DR: The model identifies acoustic and structural features produced by singing humpback whales that may facilitate a singer's ability to interpret changes in echoic scenes and suggests that interactive signal coordination by singing whales may help them to avoid mutual interference.

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Journal Article•10.1121/1.5001502

Changes in humpback whale singing behavior with abundance: Implications for the development of acoustic surveys of cetaceans

Michael J. Noad, +2 more

- 26 Sep 2017

- Journal of the Acoustical Society of Ame...

TL;DR: Singing in humpback whales is a poor predictor even of relative abundance and illustrates the caution required when developing acoustic survey techniques particularly when using social vocalizations.

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•Journal Article•10.3389/fmars.2023.1083583

The occurrence of humpback whales across the Hawaiian archipelago revealed by fixed and mobile acoustic monitoring

Marc O. Lammers, +8 more

- 26 Jan 2023

- Frontiers in Marine Science

TL;DR: In this article , a combination of moored acoustic recorders and a Wave Glider autonomous surface vehicle were used to acoustic monitor eight locations and survey approximately 1500 km of the Hawaiian archipelago for the occurrence of humpback whale song during the 2019-2020 breeding season.

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References

Journal Article•10.1139/Z84-282

Aggressive behavior between humpback whales (Megaptera novaeangliae) wintering in Hawaiian waters

C. Scott Baker, +1 more

- 01 Oct 1984

- Canadian Journal of Zoology

TL;DR: Repeated observations of individually identified whales indicate that escorting and singing are interchangeable reproductive roles of mature males, and incidents of aggression show a seasonal increase and decrease that parallel changes in abundance and average abundance.

...read moreread less

•Journal Article•10.1111/J.1748-7692.2001.TB01297.X

Acoustic detections of singing humpback whales in deep waters off the british isles

Russell A. Charif, +2 more

- 01 Oct 2001

- Marine Mammal Science

TL;DR: In this article, the authors used bottom-mounted hydrophone arrays to monitor deep-water areas north and west of the British Isles for songs of humpback whales (Megupteru novaeangliae).

...read moreread less

...

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Humpback whale-generated ambient noise levels provide insight into singers' spatial densities

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AI Agents for this Paper

Most frequently asked questions

1. What are the contributions in "Humpback whale-generated ambient noise levels provide insight into singers' spatial densities" ?

2. What are the only unknown parameters in Eq. (3)?

3. What can be used to estimate d?

4. What was the way to count whales?

5. What is the reason that the circle never becomes infinite?

6. What is the advantage of using nightly peaks?

7. What is the sensitivity of ambient noise levels to changes in the singers’ relative population size?

8. What is the effect of the spatial density of the singers?

9. What is the reason for using dB units to describe ambient noise levels?

10. What is the main reason why the humpback whales are not a good candidate?

11. What is the effect of the humpback whales on the ambient noise levels?

12. What is the trend of humpback whale density?

Figures

Citations

An update to the methods in Endangered Species Research 2011 paper "Estimating North Pacific right whale Eubalaena japonica density using passive acoustic cue counting"

Fluctuations in Hawaii’s humpback whale Megaptera novaeangliae population inferred from male song chorusing off Maui

The Sonar Model for Humpback Whale Song Revised.

Changes in humpback whale singing behavior with abundance: Implications for the development of acoustic surveys of cetaceans

The occurrence of humpback whales across the Hawaiian archipelago revealed by fixed and mobile acoustic monitoring

References

Aggressive behavior between humpback whales (Megaptera novaeangliae) wintering in Hawaiian waters

Acoustic detections of singing humpback whales in deep waters off the british isles

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