Extrapolating beyond chinchillas: ocean noise behavioral response ambiguity and noise sensitivity patterns across species
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The document discusses the variability in behavioral responses of marine species to anthropogenic noise, with a focus on how individual sensitivity and context contribute to this variability. It draws parallels with human reactions to wind farm noise, highlighting the nuanced effects on both populations and individuals. Additional considerations include the implications for marine species' health, particularly in stressed populations, and how chronic noise exposure can mask key communication signals, affecting foraging and social behaviors.
Extrapolating beyond chinchillas: ocean noise behavioral response ambiguity and noise sensitivity patterns across species
- 1. Cork, Ireland August 18, 2010Extrapolating Beyond Chinchillas:Behavioral response ambiguitythrough the lens of variable human response to wind farm noiseJim Cummings, Executive Director cummings@acousticecology.org AEInews.org AcousticEcology.org
- 2. Behavioral responsesWe can only observe (often subtle or ambiguous) behavioral changesin response to anthropogenic noiseWe can’t inquire about ocean creatures’ experience:why they do–or do not–shift their behavior
- 3. Behavioral responsesThe differences we see are often context-dependent,and there is likely more than context at workphoto John Calambokidis, Cascadia Research As with context, individual sensitivity is likely to bea major factor at low to moderate noise levels
- 4. Behavioral responsesIt’s clear there is variability in behavioral response to noise among ocean species, and between individuals in a populationor during different activitiesSouthall et al (2007): all studies of behavioral responses of low-frequency cetaceans (baleen whales) to multiple pulse noise (airguns and sonar)Migrating bowheads120dB: dramatic increase/concentration of fairly significant changesYet this is largely a specific case…otherwise, no clear dose-response:150-160dB: responses range 0 to 7 on the severity scale160+dB: severity of response clusters at 0 and 6
- 5. Questions about behavioral variability areespecially pressing when we consider these possibilities:Is a subset of the population more noise-sensitive?…and if so, being disproportionately affected by repeated exposures to chronic noise sources?cornforthimages.comAre animals moving a moderate distance,out of harmful or “very annoying” range?…while experiencing elevated stress levels even as they engage in normal activities?
- 6. What does the animal hear: softest audible / loudest tolerable?Hard to quantify: no direct measurements of many ocean species Extrapolation from easier-to-study animalsIncluding, most notably, chinchillasHow does the experience of an animal that is displaceddiffer from that of one who appears unaffected?Essentially impossible to answer: no way to assess or inquirePerhaps another leap of extrapolation is in orderSeeking clues about individual variability in experienceHow much disturbance is cause for concern?
- 7. What does the animal hear: softest audible / loudest tolerable?Hard to quantify: no direct measurements of many ocean species Extrapolation from easier-to-study animalsIncluding, most notably, chinchillasHow does the experience of an animal that is displaceddiffer from that of one who appears unaffected?Essentially impossible to answer: no way to assess or inquirePerhaps another leap of extrapolation is in orderSeeking clues about individual variability in experienceHow much disturbance is cause for concern?
- 8. What does the animal hear: softest audible / loudest tolerable?Hard to quantify: no direct measurements of many ocean species Extrapolation from easier-to-study animalsIncluding, most notably, chinchillasHow does the experience of an animal that is displaceddiffer from that of one who appears unaffected?Essentially impossible to answer: no way to assess or inquirePerhaps another leap of extrapolation is in orderSeeking clues about individual variability in experienceHow much disturbance is cause for concern?
- 9. Clues from wind farm neighborsNot unlike ocean noisebehavioral responses:No absolute dose-responseAnnoyanceSleep disruption RelocationMuch ambiguity; some trendsPattern of a minorityshowing more disruptionOften a significant minority10-45%
- 10. Clues from wind farm neighborsRating annoyance on a scale of 1 to 51: Do not noticeAudible, but not annoyedSlightly annoyedRather annoyed5: Very annoyedAs wind turbine noise increases above ambient, annoyance spikes (lower three segments)AND, a large proportion of those who hear the soundare not particularly bothered (biggest segment)Pedersen E, Waye K. Wind turbines—low level noise sources interfering with restoration experience? Environmental Research Letters 3 (2008) 015002
- 11. Clues from wind farm neighbors“Annoyed” =4 or 5 on a 1-5 scaleRural areasMostly ruralSuburbanIn quiet rural areas, annoyance rates of 25-45%as turbine noise reaches and passes about 10dB over ambient(While roughly half hear it and are still not bothered)Approaching the 50% response threshold sometimes usedin ocean noise managementKerstin Persson Waye. Perception and environmental impact of wind turbine noise. Internoise 2009.
- 12. Clues from wind farm neighborsWhat can wind farm neighbors tell us about their varied experiences as annoyance moves up toward 50%,while another half continues to be unaffected? (similar to the variability we see in responses to ocean noise)“It doesn’t sound any different than when you’ve got the dishwasher running in your house. I have a brook by my house, and I hear that more than I hear the turbines”
- 13. Clues from wind farm neighborsWhat can wind farm neighbors tell us about their varied experiences as annoyance moves up toward 50%,while another half continues to be unaffected? (similar to the variability we see in responses to ocean noise)“As I watched the first rotation of the giant blades from our deck, my sense of wonder was replaced by disbelief and utter shock as the turbine noise revved up and up, past the sound of our babbling brook”
- 14. Clues from wind farm neighborsWhat can wind farm neighbors tell us about their varied experiences as annoyance moves up toward 50%,while another half continues to be unaffected? (similar to the variability we see in responses to ocean noise)“You get a little whooshing sound once in a while. That doesn’t bother me.”
- 15. Clues from wind farm neighborsIs the impact on the minority that is more affected“negligible” or otherwise of minimal concern?“It’s like a jet that never arrives. It’s not for me; it’s an invasion.”He and his wife are selling their retirement house, a permanent“displacement effect”
- 16. Noise sensitivity research“Sounds can evoke different responses from individuals… Some people can dismiss and ignore the signal, while for others, the signal will grow and become more apparent and unpleasant over time. These reactions have little relationship to will or intent, and more to do with past exposure history and personality.”Minnesota Department of Health, Public Health Impacts of Wind Turbines, 2009
- 17. Noise sensitivity researchClear individual spectrum of psychological and behavioral sensitivity to new noise intrusions among humans(unrelated to auditory sensitivity)20%50%30%Noise sensitive: May find new soundsmore threateningActive “orienting response”Any above-audible soundslikely to beattention-grabbingNoise tolerant: Rarely perturbed evenby loud soundsPays relatively littleattention to newsoundsModeratelynoise sensitive:Reactions are moresound- and situation-dependentIs there a similar individual variabilityamong marine species?
- 18. Wildlife and wind farmsNo studies that unequivocally separate noise effects from other disruptive factorsBest bird study is from UK, showing the same speciesand individual variability we see in the ocean12 nesting species assessed7 showed significant avoidance (up to 800m) 2 more showed some avoidanceOf those with clear avoidance, varying proportions of population affected:SpeciesPopulation reduction within 500m
- 19. Wildlife and wind farmsNo studies that unequivocally separate noise effects from other disruptive factorsBest bird study is from UK, showing the same species and individual variability we see in the ocean12 nesting species assessed7 showed significant avoidance (up to 800m) 2 more showed some avoidanceOf those with clear avoidance, varying proportions of population affected:SpeciesMeadow pipitPopulation reduction within 500m15%
- 20. Wildlife and wind farmsNo studies that unequivocally separate noise effects from other disruptive factorsBest bird study is from UK, showing the same species and individual variability we see in the ocean12 nesting species assessed7 showed significant avoidance (up to 800m) 2 more showed some avoidanceOf those with clear avoidance, varying proportions of population affected:SpeciesMeadow pipitPlover, Curlew, Buzzard, WheatearPopulation reduction within 500m15%38-45%
- 21. Wildlife and wind farmsNo studies that unequivocally separate noise effects from other disruptive factorsBest bird study is from UK, showing the same species and individual variability we see in the ocean12 nesting species assessed7 showed significant avoidance (up to 800m) 2 more showed some avoidanceOf those with clear avoidance, varying proportions of population affected:SpeciesMeadow pipitPlover, Curlew, Buzzard, WheatearSnipe, Hen harrierPopulation reduction within 500m15%38-45%47-53%Pearce-Higgins et al, The distribution of breeding birds around upland wind farms. J. Applied Ecol. 2009 doi: 10.1111/j.1365-2664.2009.01715.x
- 22. Wildlife and noiseA rare study with a design that separated out noise effectsfrom habitat disruption effectsBird nesting around oil and gas installations in Alberta forestsComparing effect of (quiet) well padand (noisy) compressor station(75-105dBA at source; audible to 1km+)Among passerines (sparrow, warbler, vireo):30% reduction in density around noisy installations as compared to quiet onesBayne, Habib, Boutin. Impacts of Chronic Anthropogenic Noise from Energy-Sector Activity on Abundance of Songbirds in the Boreal Forest. Conservation Biology, Volume 22, No. 5, 2008, 1186-1193. DOI: 10.1111/j.1523-1739.2008.00973.x
- 23. Clear spectrum of individual psychological and behavioral sensitivity(unrelated to auditory sensitivity)20%50%30%Noise sensitive: May find new soundsmore threateningActive “orienting response”Any above-audible soundslikely to beattention-grabbingNoise tolerant: Rarely perturbed evenby loud soundsPays relatively littleattention to newsoundsModeratelynoise sensitive:Reactions are moresound- and situation-dependentIs there an interspecies trend here that’s reflected in behavioral responses to moderate noise?
- 24. Considerations for Marine SpeciesIf a minority of a population is more sensitive to disruption by noise,the implications are particularly relevant in situations where anegative impact on a minority of the population may beproblematic for population health and vitality
- 25. Considerations for Marine SpeciesIf a minority of a population is more sensitive to disruption by noise,the implications are particularly relevant in situations where anegative impact on a minority of the population may beproblematic for population health and vitalityStressed populations(e.g., North Atlantic Right whale)
- 26. Considerations for Marine SpeciesIf a minority of a population is more sensitive to disruption by noise,the implications are particularly relevant in situations where anegative impact on a minority of the population may beproblematic for population health and vitalityStressed populations(e.g., North Atlantic Right whale)Sensitive times of life(mating; birth and nursing; old age?)
- 27. Considerations for Marine SpeciesIf a minority of a population is more sensitive to disruption by noise,the implications are particularly relevant in situations where anegative impact on a minority of the population may beproblematic for population health and vitalityStressed populations(e.g., North Atlantic Right whale)Sensitive times of life(mating; birth and nursing; old age?)Situations in which synergistic effects with other factors(e.g., habitat degradation, toxins)may be triggered bynoise-related stress
- 28. Considerations for Marine SpeciesReduced foraging in response to moderate noiseBoats and foragingTour boats disrupt foraging common dolphins:Proportion of time spent foraging dropped by 28%(from 35% to 25% of the time)Length of each foraging period dropped by 40%(from 10 minutes to 6 minutes)Time until return to foraging increased 56%(from 9 minutes to 14 minutes)21% decrease in foraging activity observed in orcas when boats are within 400m(from 76% to 60% of the time)Stockin, Lusseau, Binedell, Wiseman, Orams. Tourism affects the behavioural budget of the common dolphin Delphinus sp. in the Hauraki Gulf, New Zealand. Mar Ecol Prog Ser 355: 287–295, 2008Williams, Bain, Smith, Lusseau. Effects of vessels on behavior patterns of individual southern resident killer whales Orcinus orca. Endangered Species Research, Vol. 6: 199-209, 2009
- 29. Considerations for Marine SpeciesReduced foraging in response to moderate noiseSonar and foragingDramatic orca foraging disruptions at moderate received levels (160dB) of MFA sonarGroup ceased foraging and moved rapidly awayUnusual dive pattern:Twice as deep (60m) as normal (20-45m)
- 30. Reversed ascent at 15m, headed back down to 60m“Potentially very significant” foraging changes in beaked whales during sonar exercises“Appear to cease vocalizing and foraging for food in the area around active sonar transmissions”Orcas: Kvadsheim, Benders, Miller, Doksaeter, Knudsen, Tyack, Nordlund, Lam, Samarra, Kleivane, Godo. Herring (slid), killer whales (spekknogger) and sonar - the 3S-2006 cruise report with preliminary results. Norwegian Defence Research Establishment (FFI). 30 April 2007Kvadsheim, Lam, Miller, Alves, Antunes, Bocconcelli, Ijsselmuide, Kleivane, Olivierse, Visser. Cetaceans and naval sonar – the 3s-2009 cruise report. Norwegian Defence Research Establishment (FFI), 01 July 2009. FFI-rapport 2009/01140Beaked whales: as reported in Nature, which received the report under a FOIA request, with the author(s) name(s) and location of the study removed. http://www.nature.com/news/2008/080801/full/news.2008.997.html
- 31. Considerations for Marine SpeciesReduced foraging in response to moderate noiseSeismic and foraging20% decrease in foraging likely among sperm whalesSWSS overall conclusionNo tagged whales made a deep foraging dive closer than 4km from active seismic arraySeveral studies show indications of whales lingering on surface near active arraysPilot whales: moved to be 1.2km from survey vessel then “exhibited a behavior best described as milling.”Humpback whales: increase in number of whales seen within visual observing range (i.e. close to vessel) when airguns are activeJochens, A., D. Biggs, K. Benoit-Bird, D. Engelhaupt, J. Gordon, C. Hu, N. Jaquet, M. Johnson, R. Leben, B. Mate, P. Miller, J. Ortega-Ortiz, A. Thode, P. Tyack, and B. Wursig. 2008. Sperm whale seismic study in the Gulf of Mexico: Synthesis report. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2008-006. 341 pp.Caroline Weir. Short-Finned Pilot Whales (Globicephalamacrorhynchus) Respond to an Airgun Ramp-up Procedure off Gabon Aquatic Mammals 2008, 34(3), 349-354.Caroline Weir. Overt Responses of Humpback Whales (Megapteranovaeangliae), Sperm Whales (Physetermacrocephalus), and Atlantic Spotted Dolphins (Stellenafrontalis) to Seismic Exploration off Angola. Aquatic Mammals 2008, 34 (1), 71-83.
- 32. Considerations for Marine SpeciesEnergetic costs of reduced foragingRob Williams et al examined the energy budgets of orcas when boats were and were not present Their striking and under-reported findings:Overall energy expenditures are only negligibly increased in the presence of boats (2-3% increase)Total energy taken in was reduced by more than 25%because of lost/disrupted foraging timeWilliams, Lusseau, Hammond. Estimating relative energetic costs of human disturbance to killer whales (Orcinus orca). Biological Conservation 133 (2006), 301-311.
- 33. Considerations for Marine SpeciesStress-related effects related to moderate noise exposureCentral to the experience of the more sensitive subset of the human population are various stress-related effects:headaches, sleep disruption, irritability, lack of concentration/focusThese clues from the experiences of humans may be especially relevant to appreciating the experiential effects of chronic noise-related stress among the more sensitive individuals in fish and cetacean populationspritchettcartoons.comWright, A.J. (ed) 2009. Report of the Workshop on Assessing the Cumulative Impacts of Underwater Noise with Other Anthropogenic Stressors: From Ideas to Action. Okeanos – Foundation for the Sea, Monterey, CA, 26-29 August, 2009.
- 34. Considerations for Marine SpeciesStress-related effects caused by masking of key signals Communication Space:A powerful new metric for considering the effects of chronic moderate noiseShipping in Stellwagen reduces the area in which whales can hear and be heard by an average of:Right whales: 84%
- 35. Fin whales: 33%Recent studies zeroing in on effects of shipping noise on fish as wellClark, Ellison, Southall, Hatch, Van Parijs, Frankel, Ponirakis. Acoustic masking in marine ecosystems: intuitions, analysis, and implication. Mar Ecol Prog Ser, Vol. 395: 201-222, 2009. GREAT VIDEO: http://news.sciencemag.org/sciencebloggers/Acoustic-space-loss_1-ship_Right-whale.movRELATED, well worth reading: Kurt Fristrup and colleagues have developed a similar metric for terrestrial sound management,introducing a metric termred the “Listening Area.” For a summary and link to this paper, see http://aeinews.org/archives/822Fish: DeRoberts, Wilson, Williamson, Guutomsen, Steinessen Silent ships sometimes do encounter more fish. ICES J. Marine Science. 2010.Simpson, SD, Meekan, MG, Larsen, NJ, McCauley, RD & Jeffs, A. 'Behavioural plasticity in larval reef fish: orientation is influenced by recent acoustic experiences', Behavioral Ecology, 2010.Slabbekoorn, Boutin, Opzeeland, Coers, ten Cate, Popper. A noisy spring: the impact of globally rising underwater sound levels on fish. TREE, 2010. doi:10.1016/j.tree.2010.04.005
- 36. Considerations for Marine SpeciesStress-related effects related to moderate noise exposureNoise-related stress(due to disrupted communication, disturbed rest,or “simply” annoyance at the sound’s presence)is likely to affectsome members of a population more than othersThe key question to keep in mind is how much a given population can tolerate such added stress in some of its members
- 37. Considerations for Marine SpeciesTolerance/habituation to moderate noise?Little evidence of habituation (a gradual shift in individuals’ responses over time)In humans: fairly well studied: some mixed results, but generally little evidence of true habituation to initially annoying noise sources – i.e., noiseremainsannoying, though they may tolerate it betterIn the oceans: few if any studies that track changes in individuals’ responses over time. So only—at best—assessing situational tolerance, not habituationWind farm planners expect tosee a “demographic shift”Permanent displacement: noise sensitive residents move away and sell homes to noise tolerant buyer(as often occurs near highways and airports)Bejder, Samuels, Whitehead, Finn, Allen. Impact assessment research: use and misuse of habituation, sensitization and tolerance in describing wildlife responses to anthropogenic stimuli. Mar Ecol Prog Ser, Vol. 395:177-185, 2009.
- 38. Considerations for Marine SpeciesConsidering context and individual sensitivityVery few humans are displaced“Home” is very inflexible (strong “site fidelity”)
- 39. Many more would move out of earshotif they could still have basic needs met: home, $Those who stay despite being bothered by noise are the most impacted by annoyance/stress effectsAnimals also have reasons to stay in noisy areasYet, can more easily act on their experiential response, rather than complain of “annoyance”Negative impacts are likely to be concentrated in the noise-sensitive subset of the population(stress, foraging disruptions, etc.)
- 40. Considerations for Marine SpeciesMajority and mean: inadequate as thresholds for determining risk and setting regulatory protectionsWind farm neighbors highlight the extremes that can occur betweendifferent individuals’ responsesto the same soundThanks to their ability to speakloudly and clearly aboutwhat theare experiencing…In ocean management, we also need to consider the implications of individual variability in noise sensitivityIf and when a significant minority of a population (15-40%?)is more dramatically (or repeatedly) affected by noise intrusions, the long-term impacts may well be far from negligible
- 41. AcousticEcology.orgAEInews.orgResources/information on all manner of sound-related environmental issues and sciencescience summaries special reports news updatesThanks to Art, Tony, and the organizing committee for making this event happen!Jim Cummings, Executive Director cummings@acousticecology.org
Editor's Notes
- #2: It’s such an honor and pleasure to be here this week among such a wonderful community of researchers. Many of you don’t know me, but over the past few years I’ve built on my background as an editor and writer on science and environmental topics, and have become useful for some in this room for my “big-picture” perspectives ocean noise issues. Today, I’m pushing that big-picture reputation to the breaking point, as I suggest that we might learn some important things about the observed ambiguity in behavioral responses to ocean noise by taking a look at how humans respond to wind farm noise. So, let’s go!
- #3: The starting point for this talk is the basic truth:Blue on slide 6 (first with wind farm picture) is #5, top oneGreen is dark green, next to bottomRed is top oneOrange is top onePurple is second from bottomBrown (name on first slide) is next to bottomBlue on headers in first section is #4 next to bottom---changed: now is top one #5
- #5: The variability in responses is seen most strikingly in this matrix from the Noise Criteria book, looking at baleen whales’ responses to multiple pulsed sounds.At the higher end of received levels, we see the full range of responses, from no change, to moderately significant changes.
- #6: This question of individual variability becomes most pressing when we consider these two possibilities:
- #7: Two key questions we address when assessing variable behavioral responses are:Most notably, in terms of stretching the extrapoloation gap, chinchillasHow does the experience of an animal whose behavior changes differ from that of one who appears unaffected?
- #8: Two key questions we address when assessing variable behavioral responses are:Most notably, in terms of stretching the extrapoloation gap, chinchillasHow does the experience of an animal whose behavior changes differ from that of one who appears unaffected?
- #9: Two key questions we address when assessing variable behavioral responses are:Most notably, in terms of stretching the extrapoloation gap, chinchillasHow does the experience of an animal whose behavior changes differ from that of one who appears unaffected?
- #10: So, here we go, pretty far afield from the ocean:We’ll hear some qualitative, experiential reports from wind farm neighbors, showing a wide range of responses to similar soundsWe’ll also look at some studies that quantify the variability in annoyance responses, and more general patterns of noise sensitivity in the population as a whole.Finally, we’ll consider some potentially biologically significant effects of ocean noise exposure that may be informed by considering the likelihood that a subset of the population is more affected by noise.
- #11: The best big picture, quantitative research to explore the qualitative responses of wind farm neighbors is a series of studies from Scandinavia, surveying at total of 1800 people living with 2.5km of wind farms.
- #13: Here’s a man who finds the turbine noise to be easy to live with
- #14: While some of his neighbors, a bit further from turbines, had the opposite reaction to the near parity of the natural ambient sound and turbines
- #15: Many people in farm country are starting to live with turbines. Some, especially those rural people who like new machines, take it in stride
- #16: But for others, the same experience has an impact that we really can’t call negligible….for this couple, there is a permanent displacement effect.
- #17: We’re seeing examples here of something that has long been recognized and understood among researchers studying the variability in response to noise among humans…..“Some people can ignore a noise, while for others, it will grow and become more apparent and unpleasant over time. These reactions have little to do with will or intent, and more to do with past exposure history and personality.”
- #18: Distinct from any differences in auditory sensitivity related to individual physiology, or age, or past extreme noise exposure, there is a well-documented and long-studied spectrum of behavioral and psychological sensitivity to noise among humans. As we go deeper into understanding marine mammal auditory thresholds, we would do well to consider the likelihood that such individual variability may well extend beyond auditory thresholds, and mimic these deeper psychological differences seen in humans.
- #19: I want to briefly mention a couple of studies of terrestrial wildlife that seem to reinforce the idea that even when disturbance occurs, there are more and less sensitive individuals among any local population
- #22: Once again, peaking at around 50% response threshold. May be interspecies common trend for moderate noise intrusions…..
- #23: And again, among species affected, a substantial minority appears more sensitive (some indications that it was older birds; ie younger ones may have been less apt to recognize the acoustic conflict)Another indication of this trend of a significant minority being more sensitive to moderate noise intrusions…..
- #24: Distinct from any differences in auditory sensitivity related to individual physiology, or age, or past extreme noise exposure, there is a well-documented and long-studied spectrum of behavioral and psychological sensitivity to noise among humans. As we go deeper into understanding marine mammal auditory thresholds, we would do well to consider the likelihood that such individual variability may well extend beyond auditory thresholds, and mimic these deeper psychological differences seen in humans.
- #25: Okay. So, as we come to grips with this pattern, also hinted at in the ocean, in which a minority of the population….Three obvious examples of when impacts on a minority may be intolerable for the population as a whole are: (these three)For any of these three, there are various types of disruption that may be problematic. I’ll close by touching on three areas in which current and ongoing research will help us to assess the importance of these questions in the ocean.
- #26: Okay. So, as we come to grips with this pattern, also hinted at in the ocean, in which a minority of the population….Three obvious examples of when impacts on a minority may be intolerable for the population as a whole are: (these three)For any of these three, there are various types of disruption that may be problematic. I’ll close by touching on three areas in which current and ongoing research will help us to assess the importance of these questions in the ocean.
- #27: Okay. So, as we come to grips with this pattern, also hinted at in the ocean, in which a minority of the population….Three obvious examples of when impacts on a minority may be intolerable for the population as a whole are: (these three)For any of these three, there are various types of disruption that may be problematic. I’ll close by touching on three areas in which current and ongoing research will help us to assess the importance of these questions in the ocean.
- #28: Okay. So, as we come to grips with this pattern, also hinted at in the ocean, in which a minority of the population….Three obvious examples of when impacts on a minority may be intolerable for the population as a whole are: (these three)For any of these three, there are various types of disruption that may be problematic. I’ll close by touching on three areas in which current and ongoing research will help us to assess the importance of these questions in the ocean.
- #31: All these foraging reductions are taking place at relatively moderate received levels
- #32: Slide first, then:The key question that remains is to what degree the animals are able to make up for lost time, so to speak, and devote more of the boat-free time to foraging, in order to rebalance their energy budgets. This line of research is especially relevant to areas in which a large proportion of the day may include noise intrusions (e.g., areas with heavy boating, or regions in which seismic surveys are present during biologically sensitive times).
- #34: Many stresses are likely to result as animals strain to hear and be heard in an increasingly noisy sonic environment. The newly-introduced metric of Communication Space is likely to yield many new insights along these lines. Already, we can see that for some species, the Communication Space can be reduced dramatically by local shipping on a routine basis: these are then, of course, the species in which we’ll need to be most conscious about the possible impacts on populations, or (as in the case of fin whales) minorities of populations.
- #35: Whatever the sources of stress, the question is, how much can a given population tolerate chronic stress in even a minority of its members?
- #36: As we consider impacts on large minorities of populations, we’ll need to be especially clear about how we assess any changes in response that we may observe. The difference between tolerance and habituation (a change in how an individual responds over time) is a subtle, yet important one to bear in mind. While some wind farm neighbors learn to tolerate the noise better, very few of those who are bothered actually habituate and are no longer annoyed. In communities with wind farms, planners expect to see some permanent displacement of the more noise sensitive. How might we be more sensitive to the possibility of such dramatic changes in ocean populations?
- #37: Animals DO have many reasons to stay in noisy areas: this is why we don’t assume it’s just tolerance/sensitivity
- #38: In both wind farm planning and ocean management it is often tempting to let the majority or the mean response become the ground for determination of risk and of regulatory protections, with minority responses considered to to be negligible impacts. However, just as communities near wind farms are coming to grips with the sometimes extreme effects on a minority of their neighbors, thanks to their ability to speak loudly and clearly about what they are experiencing, so too should ocean policy makers take into consideration the implications of individual variability in sensitivity to noise. If and when a significant minority of a population is more dramatically or repeatedly affected by noise intrusions, the long-term impacts on populations are likely to be far from negligible.