Oceans of noise - Whale and Dolphin Conservation Society

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5.3 Longer-term impactsNoise is clearly biologically significant if it induces long-term abandonment of an area importantfor feeding, breeding or rearing the young, as it may lead to reduced fecundity, carrying capacity,or both (Richardson 1997). Consequences will not become apparent until more research isconducted into the long-term effects of noise pollution.5.3.1 Sensitisation and habituationSensitisation occurs, when, for example, an animal has been exposed to a painful level of noisefrom a particular source, causing it to avoid the source. Habituation occurs when the stimulus isno longer novel although adverse consequences may still be associated with it. Weilgart (1997)noted that damage from very intense sound might not be obvious at sea, especially in the shortterm.Marine mammals are intractable animals to study in the wild and auditory damage is almostimpossible to detect in free-ranging large whales. Gradual deafness might easily bemisinterpreted as a growing tolerance or habituation to noise.5.3.2 StressStress is a condition often associated with the release of adrenocorticotrophic hormone (ACTH)or cortisol. It is recognised that noise and disturbance lead to an increase in activity of glandsproducing these hormones (Welch and Welch 1970). Increases in these hormone levels areusually associated with changes in behaviour, such as increased aggression, changes in respirationpatterns or altered social behaviour. However, noise-induced stress may be present but does notnecessarily cause overt changes in behaviour (Thomas et al. 1990).Prolonged noise-induced stress can lead to debilitation, e.g., in fish and invertebrates, prolongedexposure can induce infertility, pathological changes in digestive and reproductive organs andreduced growth (Banner and Hyatt 1973; Lagadere 1982). Prolonged exposure to high levels ofnoise and the resultant chronic activation of stress-related hormonal complexes could lead toharmful effects in cetaceans (Seyle 1973; Thomson and Geraci 1986; St Aubin and Geraci 1988),for example:• Arteriosclerosis (Radcliffe et al. 1969)• Nutritional problems (Smith and Boyd 1991)• Stomach ulceration (Brodie and Hanson 1960)• Suppression of reproductive function (Moberg 1985)• Reduction in resistance to infection (Cohn 1991).• Decrease in life expectancy (Small and DeMaster 1995)5.3.3 Physiological damage to tissues and organsThe sudden pressure changes cause by intense noise can result in actual physiological damage.Ketten (1995) divides the physiological effects of intense noise into two categories:1) Lethal blast injuries;2) Sub-lethal acoustic trauma.Lethal effects are those that result in the immediate mortality or serious debilitation of animals inor near an intense noise source (e.g. submarine blasting). Sub-lethal effects occur when sound57
levels exceed the ear’s tolerance, i.e. auditory damage results from metabolic exhaustion or overextensionof one of the ear’s components. Sub-lethal, noise-induced trauma is possible as a resultof high levels of shipping noise, for instance. Sub-lethal impacts can lead indirectly to death incetaceans as they render animals unable to detect prey or predators and also make them unable toorientate and avoid shipping traffic or obstacles.Ketten (1995) divides acoustic trauma resulting from intense noise levels into three categories:1) Mild (recovery possible), e.g. pain, vertigo, tinnitus, hearing loss, tympanic tears.2) Moderate (partial hearing loss), e.g. otis media, tympanic membrane haematoma, serum orblood in the inner ear, dissection of the mucosa.3) Severe (permanent hearing loss and damage), e.g. ossicular fracture or dislocation, round/ovalwindow rupture, CSF leakage into the inner ear, cochlear and saccular damage.Sound at any level can cause hearing damage by decreasing auditory sensitivity. One of the mostcommon mild traumatic effects is a threshold shift. The auditory threshold of a sound is theminimum level of intensity at which a sound can be heard. After this level of auditory trauma, thethreshold becomes higher and hearing sounds becomes more difficult. Threshold shifts may betemporary (TTS), or can be permanent with greater intensities of noise. Multiple or longer periodsof exposure to noise levels causing TTS can also cause permanent threshold shifts (PTS). Thesethreshold shifts are caused by hair cell fatigue, hair cell damage or nerve degeneration.Submerged humans exposed to underwater source sounds at intensities of 150-180 dB (re 1 µPa;0.7-5.6 kHz) suffered TTS. This could be used as a rough guideline for sound intensities thatcould cause TTS in cetaceans, though the greater sensitivity of the cetacean ear and the moreefficient coupling of sound with the cetacean body may require a more conservative view.It has been suggested that some hearing impairment has led to the deaths of sperm and humpbackwhales in industrial areas as they are unable to detect potential threats e.g. boat traffic and fishinggear (Lien et al. 1993; Andre in Moscrop 1997).Significant, physiological impacts repeatedly go undetected, as we don’t have the ability to detectand assess them. Even carcasses are very rarely encountered at sea, as they sink relativelyquickly. There is no way to quantify such impacts.5.3.4. Understanding of biological significanceThe impact of noise pollution on non-migrating animals or animals engaged in a more localisedactivity such as calving or feeding is probably most significant over the longer term. For example,continual displacement from these areas by sustained noise pollution could have a much moreprofound and serious effect on individual animals at a population level.Consequences will not become apparent until more research is conducted into the long-termeffects of noise pollution. This is difficult in areas where minimal information about cetaceandistribution is available.58
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Oceans of Noise 2004A WDCS Science
Page 8 and 9: In the US, the deployment of Low Fr
Page 10 and 11: its propagation beyond those declar
Page 12 and 13: The best evidence for noise being f
Page 14 and 15: Box 1. Characteristics of sound / l
Page 16 and 17: Sound speed (c)The speed (c) of a w
Page 18 and 19: Box 2. The effects of temperature,
Page 20 and 21: 2.1.2. Measuring sound intensityIde
Page 22 and 23: i.e. Equal pressure measurements di
Page 24 and 25: Spherical or Geometrical spreading
Page 28 and 29: 5.0 145Tug pulling loaded barge 1.0
Page 30 and 31: The source used during 3-D surveys
Page 32 and 33: Machinery noisePropulsion machinery
Page 34 and 35: Man-made islands /caissonsFixed pla
Page 36 and 37: 12 3245Drill bit6Figure 3.4. Sound
Page 38 and 39: Transientnoise sourcesAircraftHelic
Page 40 and 41: Results from the aerial surveys con
Page 42 and 43: haemorrhaging in the inner ears and
Page 44 and 45: However they also noted that whales
Page 46 and 47: 4. The Use of Sound by CetaceansChr
Page 48 and 49: seems logical, therefore, that if t
Page 50 and 51: However, despite the reported low a
Page 52 and 53: Kamminga and Wiersma 1981;Akamatsu
Page 54 and 55: SongSocial callsShrieksSlaps0.03-80
Page 56 and 57: anthropogenic factors that make the
Page 60 and 61: 5.4 Indirect impactsThe above impac
Page 62 and 63: decompression sickness (DCS) as see
Page 64 and 65: 6. Examples of regional and nationa
Page 66 and 67: 6.3 ASCOBANS and ACCOBAMSTwo region
Page 68 and 69: implications and the discussion sho
Page 70 and 71: 7.1. Consideration of Voluntary vs.
Page 72 and 73: acoustic measurements have been mad
Page 74 and 75: 7.6. Methods of protectionComplianc
Page 76 and 77: 7.6.1 Monitoring7.6.1.1 Visual, aco
Page 78 and 79: Delory et al. (2002) use Ambient No
Page 80 and 81: 8. ReferencesAburto, A., Rountry, D
Page 82 and 83: Caldwell, M.C., Caldwell, D.K., and
Page 84 and 85: Engas, A., Lokkeborg, S., Ona, E. a
Page 86 and 87: IWC 2002b. Report of the Scientific
Page 88 and 89: McCauley, R.D. 1994. Seismic Survey
Page 90 and 91: Potter, J. and Delory, E. 2001. Noi
Page 92 and 93: Smolker, R.A., Mann, J. and Smuts,
Page 94 and 95: Watkins, W.A. 1981b. The activities
Page 96 and 97: ANNEX 1The Application of Marine Po
Page 98 and 99: an important factor. 13 The judgeme
Page 100 and 101: in the preparatory work of the LOSC
Page 102 and 103: practice by the UNEP Governing Coun
Page 104 and 105: protection and preservation of the
Page 106 and 107: than international rules, standards
Page 108 and 109:
Four of the twelve regional seas tr
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seismic operations in the Protocol
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ConclusionAt the global level, only
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Art 209 LOSC focuses on both standa
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No State Party may impose condition
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coastal States”. This formulation
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If the IMO makes this determination
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estrictions to vessels operating in
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In the EEZ, in comparison to the te
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Appendix A - Some international ins
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Convention for the Protection of th
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Available at:http://www.unep.ch/sea
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BucharestConventionArticle XIPollut
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environment1. The Contracting Parti
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- that under Article III.8.c) of AC
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e) no sudden or repeated change in
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Ref: Nowacek et al. 2001.Location:
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Location: Arctic• Vocal behaviour
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• Vaquita surfacing duration and
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• 6% of small delphinids (n=264;
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Species type: Boto, Inia geoffrensi
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• Humpback whales appeared tolera
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• Behaviour interpreted as aggres
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• There was no evidence of minke
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• Northern right whales may be ap
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• Migrating gray whales disturbed
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to Ensenada De La Paz, Mexico. Aqua
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distribution of humpback whales, Me
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Richardson, C.R. Greene, C.I. Malme
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Zhou, K., Pilleri, G. and Li, Y. 19
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6. surveys for Cuvier’s beaked wh
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