Oceans of noise - Whale and Dolphin Conservation Society

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SONAR TYPE FREQUENCY RANGE (KHZ) AV. SOURCE LEVEL (dB re 1 uPa/1 a) 53C sonar used during Bahamas stranding 6.8, 8.2 245 Search and surveillance 2-57 230+ 56 sonar used during Bahamas stranding 2.6, 3.3 223 Mine & obstacle avoidance 25-200 220+ Weapon mounted sonar 15-200 200+ Low Frequency Active Sonar (LFAS) used by 0.25-3.0? 230+ NATO Surveillance Towed Array Sensor System c. 0.1-0.5 215-240 (SURTASS) Low Frequency Sonar (LFA) SONAR 2087 (UK Royal Navy Low Frequency Sonar System) c. 0.1-0.5 200 Several studies have voiced concern over the potential impacts of military activities upon cetaceans. Vonk and Martin (1989), Simmonds and Lopez-Jurado (1991), Frantzis (1998) and Frantzis and Cebrian (1999) have all suggested that loud military noise may have caused mass strandings of beaked whales in the Canary Islands and the Ionian Sea. The Greek stranding was found to coincide with the testing of military sonar. Moreover, sperm whales and long-finned pilot whales have both demonstrated changes in vocal behaviour in response to the use of military sonar (Watkins et al. 1985; Rendell and Gordon 1999) and Parsons et al. (2000) reported a significant decrease in minke whale sightings during NATO exercises in West Scotland, during which active sonar was being used by military vessels. Rowles et al. (2000) reported that of 49 reports of beaked whale mass strandings, 8 have been associated with military activities, and all of those have involved Cuvier’s beaked whale, Ziphius cavirostris, as the principal species (see also Simmonds and Lopez-Jurado, 1991). Professor Hal Whitehead (a renoun whale biologist) comment on the significance of these data, in a letter to Donna Wieting of NMFS (the US National Marine Fisheries Service) dated May 1, 2001, wrote: “The International Whaling Commission’s Standing Working Group on Environmental Concerns reported that 8/49 beaked whale strandings, and 6/6 multiple species beaked whale strandings occurred with “military activities”. We do not know the rate of occurrence of “military activities”, but, by assuming rates, it is possible to calculate the probability of these numbers of coincidences (or more) between strandings and military activities, under the null hypothesis that they are unrelated. In fact the probability that 8/49 (or more) beaked whale strandings occurred with military activities to be greater than p=0.05 (the usually accepted level for rejection of a null hypothesis), military activity would have had to occur more than 8.4% of the time, and for the probability that 6/6 multiple beaked whale strandings occurred with military activities to be greater than p=0.05, military activity would have had to occur more than 60.7% of the time. The actual rate of military activities in any area is probably nearer 0.1%. Thus, the number of strandings of beaked whales with military activities is very unlikely to be a coincidence. Military activities are strongly implicated in these events” (Whitehead pers comm.). Another mass stranding of 17 cetaceans (including two species of beaked whales and minke whales) occurred in March 2000, in the Bahamas. A US governmental report has determined that mid-frequency sonar (3-7 kHz) being used in a US military exercise was responsible for this mass stranding (Weiss, 2001). Researchers reported that the whales demonstrated signs of 39
haemorrhaging in the inner ears and cranial air spaces, consistent with impulsive trauma - i.e. intense, loud sound, that did not come from a nearby explosion (Balcomb and Claridge 2001). The levels of sound that would have been received by the whales were estimated to be between 140 dB and 160 dB. The researchers calculated that the frequencies produced by the midfrequency sonar system employed, at that received level, could cause resonance in the cranial air spaces of the cetaceans (Balcomb and Claridge 2001). This resonance could cause haemorrhaging (as had been observed in the stranded animals), disorientation and an inability to navigate and echolocate. However, this is only one theory. Other possible mechanisms to explain the injuries observed include static or rectified diffusion in which intense acoustic exposure could cause a type of compression sickness in whales (similar to the “bends”, as seen in human divers), and perhaps especially the deep divers, by stimulating bubble formation or growth in the whales’ tissues (Houser et al. 2001). (This matter is considered in more detail later in this report.) Two sonar systems are currently in the process of being introduced: in the US (SURTASS LFA) and the UK (SONAR 2087). Both rely on low frequency sound to determine military targets. Other countries already operate, or plan to operate, similar systems. There has, however, been considerable concern over these proposed systems, because of: i. the loudness of the sources; ii. iii. the distance that the sounds may travel, because of their low frequency nature; and tests that have demonstrated short-term behavioural changes in cetaceans in response to the sonar. For example, blue and fin whales demonstrated possible vocal responses, gray whales displayed avoidance of the noise during their migration, and humpback whales temporarily stopped singing and lengthened the duration of their song. These responses occurred when the whales received the source at levels of 155dB, and even as low as 115-125dB. The operational source level of the sonar system will, however, be well over 200dB (US Navy 2001), thus potentially exposing any whales in close proximity to much louder levels than those which can induce these observed behavioural changes. In addition to sonar, submarine-to-submarine communications systems are also a substantial source of submarine sound: the systems produce sounds of 5-11 kHz at source levels of 180-200 dB (Richardson et al. 1995). Moreover, explosives used in military tests and exercises can be a considerable source of underwater noise with source levels of 267 dB in a 0.45-7.07 kHz range (Evans and Nice 1996; Perry 1998). A recent victory for cetaceans came in a 2002 court decision to limit the use of the US Navy LFAS. The area of operation has temporarily been reduced to a large part of the Pacific Ocean focused around the remote Mariana Islands - an estimated area of one million square miles. While this is a substantial area of ocean, it’s only about 10-15% of the area for which the U.S. regulators originally proposed permits (NMFS, 2002). As the military undertake activities in all the waters of the world, their potential encroachment of cetacean habitats is considerable. Because public information on the exact nature and extent of military activities is highly restricted, the total impact of the military’s ensonification of the world’s oceans will be difficult to quantify. 3.8. Purposeful scaring of marine mammals 3.8.1 Acoustic Harassment Devices (AHDs) The finfish aquaculture industry suffers predation by seals and other marine mammals and, in response, acoustic harassment devices (AHDs) or ‘seal-scrammers’ have been developed to deter 40
Page 1 and 2: Oceans of noise A WDCS Science repo
Page 3 and 4: Contents Author biographies 4 Prefa
Page 5 and 6: Author biographies Sarah Dolman Sar
Page 7 and 8: Preface Over the course of the last
Page 9 and 10: • subject to full environmental a
Page 11 and 12: The best evidence for noise being f
Page 13 and 14: Box 1. Characteristics of sound / l
Page 15 and 16: Sound speed (c) The speed (c) of a
Page 17 and 18: Box 2. The effects of temperature,
Page 19 and 20: 2.1.2. Measuring sound intensity Id
Page 21 and 22: i.e. Equal pressure measurements di
Page 23 and 24: Spherical or Geometrical spreading
Page 25 and 26: 3. Sources of Marine Noise Chris Pa
Page 27 and 28: 5.0 145 Tug pulling loaded barge 1.
Page 29 and 30: The source used during 3-D surveys
Page 31 and 32: Machinery noise Propulsion machiner
Page 33 and 34: Man-made islands / caissons Fixed p
Page 35 and 36: 1 2 3 2 4 5 Drill bit 6 Figure 3.4.
Page 37 and 38: Transient noise sources Aircraft He
Page 39: Results from the aerial surveys con
Page 43 and 44: However they also noted that whales
Page 45 and 46: 4. The Use of Sound by Cetaceans Ch
Page 47 and 48: seems logical, therefore, that if t
Page 49 and 50: However, despite the reported low a
Page 51 and 52: Kamminga and Wiersma 1981; Akamatsu
Page 53 and 54: Song Social calls Shrieks Slaps 0.0
Page 55 and 56: anthropogenic factors that make the
Page 57 and 58: 5.3 Longer-term impacts Noise is cl
Page 59 and 60: 5.4 Indirect impacts The above impa
Page 61 and 62: decompression sickness (DCS) as see
Page 63 and 64: 6. Examples of regional and nationa
Page 65 and 66: 6.3 ASCOBANS and ACCOBAMS Two regio
Page 67 and 68: implications and the discussion sho
Page 69 and 70: 7.1. Consideration of Voluntary vs.
Page 71 and 72: acoustic measurements have been mad
Page 73 and 74: 7.6. Methods of protection Complian
Page 75 and 76: 7.6.1 Monitoring 7.6.1.1 Visual, ac
Page 77 and 78: Delory et al. (2002) use Ambient No
Page 79 and 80: 8. References Aburto, A., Rountry,
Page 81 and 82: Caldwell, M.C., Caldwell, D.K., and
Page 83 and 84: Engas, A., Lokkeborg, S., Ona, E. a
Page 85 and 86: IWC 2002b. Report of the Scientific
Page 87 and 88: McCauley, R.D. 1994. Seismic Survey
Page 89 and 90: Potter, J. and Delory, E. 2001. Noi
Page 91 and 92:
Smolker, R.A., Mann, J. and Smuts,
Page 93 and 94:
Watkins, W.A. 1981b. The activities
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ANNEX 1 The Application of Marine P
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an important factor. 13 The judgeme
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in the preparatory work of the LOSC
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practice by the UNEP Governing Coun
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protection and preservation of the
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than international rules, standards
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Four of the twelve regional seas tr
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seismic operations in the Protocol
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Conclusion At the global level, onl
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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/se
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Bucharest Convention Article XI Pol
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environment 1. The Contracting Part
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- that unde r A rticle III .8.c) of
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e) no sudden or r epeated change in
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Ref: Nowacek et al. 2001. Location:
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Location: Arctic • Vocal behaviou
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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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