AcousticEcology.org Special Report
International Whaling Commission
Anchorage, Alaska, USA
May 28-31, 2007
IWC Web Info and Downloads
Scientific Committee report: Download sections [GO THERE]
Main report, including SOCER as an appendix [DOWNLOAD (pdf)]
Annex K (environmental concerns, including noise) [DOWNLOAD (pdf)]
Annex M (whalewatching) [DOWNLOAD (pdf)]
List of papers [DOWNLOAD (pdf)]
This year’s IWC meeting, and the work of the Scientific Committee in particular, included far fewer notable noise-related developments than the previous three meetings (each also summarized in an AEI Special Report: [GO THERE]). Indeed, looking forward, the Scientific Committee priorities for the next year set anthropogenic noise as a topic to be addressed only “if there is time and documentation available.” Nonetheless, there were several interesting new papers discussed, as well as continued expansion of consideration of the effects of whalewatching, including plans for a special pre-meeting workshop at next year’s IWC meeting in Chile, to plan a global research program on whalewatching.
Among the most striking contributions were:
- New data indicating that seismic surveys can be heard over thousands of kilometers [ANCHOR]
- A groundbreaking paper that challenges assumptions about habituation to noise, suggesting that what we see as habituation is more often a reflection of individual tolerance levels [ANCHOR]
- New information on several strandings in Taiwan that were coincident with naval exercises [ANCHOR]
- The first observations of beaked whale dive patterns being changed by a passing ship, reducing foraging efficiency by 50% [ANCHOR]
The Scientific Committee’s standing working group (SWG) on environmental concerns addresses noise as one of its routine topics. In recent years, special workshops (on Anthropogenic Noise in 2004 and Seismic Surveys in 2006) addressed noise issues in particular; this year, there was less focus on noise, but still some interesting developments:
The Scientific Committee made a point of reiterating its concerns about the impacts of mid-frequency active sonar, and urging that best practice mitigation measures be taken, including keeping sonar source levels below 230dB and monitoring beaches near training missions, with a response team in place in case of strandings. In particular, the Committee asked that such measures be in place for this summer’s planned Talisman Sabre 2007 training off Australia; the Australian government does plan to follow procedures much in line with the recommendations. It was noted that mid-frequency sonar will no longer be deployed around the Canary Islands, where strandings have occurred in the past; instead, these exercises have been moved to the Cape Verde Islands. Among the recommendations of the Committee are calls for standardized response and necropsy protocols, including study of the entire animal (since to date no direct acoustic trauma has been observed in sonar-related strandings; rather, evidence of decompression-type effects such as tissue lesions have been the predominant physiological effect). These efforts could identify other shared pathologies in stranding events; also, there was a call to investigate loud natural sounds, such as earthquakes, to stranding events.
A report of unusual stranding events in Taiwan in 2004 and 2005 including some that took place during military exercises. In February 2004, a joint US/Philippines military exercise began in waters 100 miles south of Taiwan. The day after the exercise began at least nine short-finned pilot whales stranded on the southeast coast of Taiwan. A week later, a ginkgo-toothed beaked whale stranded on the southwest coast. The latter had internal injuries suggestive of acoustic or impulsive-induced trauma. The exercise ended in early March and on the same day a mass stranding of short-finned pilot whales occurred in neighboring China, followed by another stranding three days later. Before 2004, there had been only two confirmed strandings of short-finned pilot whales in Taiwan. In February the following year, two mass stranding events of live pygmy killer whales in southwest coastal areas occurred, along with a milling event wherein another group entered a shallow coastal harbour. Two Risso’s dolphins also stranded. Examined animals displayed signs of acoustic trauma. Between 19 July and 13 August 2005, there were 22 strandings events involving several species (including dwarf sperm whale, pantropical spotted dolphin, striped dolphin and Blainville’s and Longman’s beaked whales); 25 animals were reported for (mostly) the northern coast of Taiwan. During July, a naval exercise was being conducted by the Chinese military in the East China Sea, and in August, a joint Japanese/ US navy exercise took place. This is the greatest rate of cetacean strandings ever recorded in Taiwan, including strandings of rarely found species such as striped dolphins. Interestingly, many of the strandings were deep diving pelagic species. Moreover, five of six examined carcasses had ‘bubbles’ in tissues, a symptom associated with sonar-induced mortality. Other possible sources of underwater noise or possible stranding-inducing factors were investigated (typhoons, underwater earthquakes and seismic surveys), but could not account for the unusual pattern of strandings. Navy sonar and/or live ammunition exercises were considered to be plausible causes for many of the stranding events: the ginkgo-toothed whale showed evidence of acoustic trauma at a time when military exercises were being conducted. A more complete and detailed pathological examination of these unusual strandings in Taiwan has been completed and will be presented as a scientific publication and at the next meeting of the SC.
Wang, J.Y. and Yang, S.-C. 2006. Unusual cetacean stranding events of Taiwan in 2004 and 2005. J. Cet. Res. Manage. 8: 283-292
Necropsies after a January 2006 mass stranding of Cuvier’s beaked whales on the Canary Islands, while NATO ships were in the area, showed “gas and fat embolic syndrome” (the newly named set of physical injuries including tissue lesions, apparently associated with sonar-induced strandings, and likely caused by disrupted dive patterns) in all four whales studied.
(SOURCE: Communicated by A. Fernández, DVM, PhD, ECVP, Veterinary Histology and Pathology Institute for Animal Health and Food Security (IUSA), Veterinary School, University of Las Palmas de Gran Canaria, Spain)
The Committee also reinforced earlier statements regarding the effects of seismic surveys, encouraging a more aggressive program to monitor populations of cetaceans before, during, and after surveys, and recommending tracking and sharing of locations and activities of survey vessels off Alaska’s north slope, as well as avoiding areas of special biological significance. It was reported to the Committee that the oil and gas industry is putting more effort into monitoring cetaceans before, during and after surveys, though the Joint Industry Research Program. The Committee expressed specific concern about development plans in the North Aleutian Basin, including Bristol Bay, and a return survey near grey whale feeding grounds off Sakhalin Island, Russia.
A review of 2006 seismic surveys off the Alaskan north slope indicated that the models used to predict the safety radius (the zone within which airgun sounds exceeded 180db (rms); when whales were observed in this zone, the airguns would be powered down), were up to 33% smaller than the radii measured in the field during the surveys. That is, the area within which whales would likely be disturbed was larger than what was modeled. The Working Group expressed concern that the models used to establish safety radii are based on smaller airgun arrays than are generally used these days, as industry attempts to image deeper into the seabed.
SC/59/E5. Moore, S.E. and Angliss, R.P. Summary of seismic surveys conducted offshore northern Alaska and western Canada, July-October 2006, with an overview of plans for 2007. 7pp.
Chris Clark reported preliminary results of a study using data from 22 autonomous recorders deployed in the Chuckchi Sea during the summer of 2006. The study was monitoring for the presence and location of beluga and bowhead whales, and measuring ambient noise levels and received levels from seismic surveys. Clark hopes to merge his acoustic data with information from industry about location and activities of survey vessels; full results should be available at next year’s meeting.
While no mention was made of follow-up from a similar preliminary collection of data presented by Clark at last year’s meeting, regarding long-range propagation of low frequency sounds from surveys (including possibly suppressing fin whale calling), a new paper shared data collected over large portions of the Southern Ocean between Australia and Antarctica, which indicated that surveys taking place over 2500km away, off the coast of Tasmania, were audible in the Southern Ocean (though the frequencies of the long-range sounds are not yet available). Another set of acoustic receivers off eastern Antarctica regularly recorded repeated low-frequency pulses similar to seismic shots, including tracking of the source, but final analysis to confirm that the source was airguns remains to be completed.
SC/59/SH5. Gedamke, J., Gales, N., Hildebrand, J. and Wiggins, S. Seasonal occurrence of low frequency whale vocalisations across eastern Antarctic and southern Australian waters, February 2004 to February 2007. 9pp.
A report from Scotland looked at a 1998 study of fin and sei whale distributions in two areas, west of the Hebrides and in the Faroe-Shetland Channel. No whales were observed in the Hebrides area, while the highest levels ever recorded were seen in the Faroe-Shetland Channel. Seismic survey activity was four times higher in the Hebrides area than in the Faroe-Shetland Channel. Changes in fin and sei whale migration patterns, and changes in abundance of prey could not be ruled out as causes; nevertheless, the authors expressed concern about increasing oil and gas development, including seismic surveys, in parts of the region important to cetaceans.
Macleod, K., M.P. Simmonds and E. Murray. 2006. Abundance of fin (Balaenoptera physalus) and sei whales (B. borealis) amid oil and gas exploration and development off northwest Scotland. J. Cetacean Res. Manage. 8(3): 247-254.
Stone, C.J and M.L. Tasker. 2006. The effects of seismic airguns on cetaceans in UK waters. J. Cetacean Res. Manage. 8(3): 247-254.
Cetacean diversity off the coast of Brazil dropped from 1994 to 2004, with a conspicuous decrease in 2000-2001. A proposed cause was an increase in seismic surveys there; significantly more surveys were conducted in 2000-2001 than in previous or subsequent years. There was a significant correlation between increasing numbers of seismic surveys and decreasing whale diversity. Other oceanographic parameters temperature, salinity and density showed no relationship to the decline. The authors suggested that non-resident, transient or more mobile species may be displaced from Brazilian waters during seismic surveys.
Parente, C.L., de Araújo, J.P. and de Araújo, M.E. 2007. Diversity of cetaceans as a tool in monitoring environmental impacts of seismic surveys. Biota. Neotrop. 7: 1-7
A study in the Gulf of Mexico, using tagged sperm whales to measure received levels of sound from seismic surveys, revealed some surprising anomalies in sound transmission. Sound levels decreased between 5 km and 9 km from the sound source, but then increased between 9 km and 13 km. Received levels “can be just as high at12 km as they are at 2 km”. Sound echoing from the seabed or reflecting from the sea surface (secondary arrivals) created “higher received levels at 5-12.6 km than at ranges closer to the seismic sources”. Thus, “if pulses with received levels in the range of 140-165 dB re. 1 uPa...are found to have negative effects on sperm whales...then animals in the Gulf of Mexico could be impacted at ranges of more than 10 km from seismic survey vessels, well beyond ranges predicted by [modelling] and beyond where visual observers on the source vessel can monitor effectively”. This casts doubt on previous assumptions that whales would move horizontally away from survey vessels: indeed, they might move vertically or even approach a vessel to avoid high sound levels. Sperm whales received sound levels of up to 162 dB (re 1 uPa (pp)) when between 4 and 12 km from the seismic survey vessel. In addition, though airguns predominantly produce low frequency sound, under 250Hz, significant higher frequency sound, above 500Hz, concentrates near the surface, where it might affect dolphins.
Madsen, P.T., Johnson, M., Miller, P.J.O., Aguilar Soto, N., Lynch, J. and Tyack, P. 2006. Quantitative measures of air-gun pulses recorded on sperm whales (Physeter macrocephalus) using acoustic tags during controlled exposure experiments. J. Acoust. Soc. Amer. 120: 2366- 2379; DeRuiter, S.L., Tyack, P.L., Lin, Y.-T., Newhall, A.E., Lynch, J.F. and Miller, P.J.O. 2006. Modelling acoustic propagation of airgun array pulses recorded on tagged sperm whales (Physeter macrocephalus). J. Acoust. Soc. Amer. 120: 4100-4114
The effects of renewable energy projects, including wind, wave, and tidal power, have been investigated only partially, generally focusing on effects of wind turbine construction and operation on resident dolphins. As far as Simmonds and co-authors are aware, there have not been any field studies to date that have looked at the impacts of wind farms on any cetaceans other than harbour porpoises. Pile-driving associated with wind farm construction presents the potential for physical trauma at short range and behavioral impacts at longer distances. The need for more comprehensive investigation of the impacts of seabed construction and operation of renewable energy projects is crucial, considering the rapid expansion taking place in this field.
SC/59/E10. Dolman, S.J., Green, M. and Simmonds, M.P. Marine renewable energy and cetaceans. 9pp.
A tagged Cuvier’s beaked whale exhibited a marked change in dive behavior when a ship passed overhead, causing a 50% reduction in foraging efficiency, as measured by dive duration and click rates. The animal experienced broad-band received levels of 135dB re 1uPa, and mid-frequency levels of 117db re 1uPa (compared to a background mean of 93dB re 1uPa during other dives).
Aguilar Soto, N., Johnson, M., Madsen, P.T., Tyack, P.L., Bocconcelli, A., and Borsani. J.F. 2006. Does intense ship noise disrupt foraging in deep-diving Cuvier’s beaked whales (Ziphius cavirostris)? Mar. Mamm. Sci. 22: 690-699
The Scientific Committee subcommittee on Whalewatching discussed papers that looked at whalewatching in many different parts of the world. Among the key developments reported on:
In Australia, the government took the unprecedented step of cutting the number of dolphin-watch companies operating in Shark Bay in half, from two to one. The subcommittee had urged such action last year, and was pleased to see their recommendation followed. Similarly, Brazil acted on suggestions of the subcommittee to increase monitoring of interactions between right whales and whalewatching boats in a protected area.
An important paper presented by Bejder, et al, addressed the need for standardizing terminology as well as discernment among explanatory mechanisms used to describe responses to noise over time. Strikingly, the authors suggest that what is generally termed “habituation” (wherein responses to a noise source decrease over time, such that we assume that animals are “getting used to it”), is more often an observation of differences in tolerance between individual animals in a population. That is, individuals with low tolerance leave or move further away, while those with higher tolerance are observed remaining nearby, so that the fact that many animals are not be able to tolerate the sound is generally missed. The SC welcomed this new perspective, and further emphasized that the absence of response does not necessarily mean an absence of impacts, i.e., there may be unseen population level impacts due to stress.
SC/59/WW2. Bejder, L., Samuels, A., Whitehead, A. and Allen, S. An ethological framework for defining habituation, sensitisation and tolerance to anthropogenic stimuli. 12pp.
An overview of recently published studies looking at compliance with whalewatching regulations included a study from Florida in which dolphin-watching vessels obeyed the close-approach regulations only 57% of the time, with about a quarter of the dolphin encounters triggering behaviors associated with disturbance.
SC/59/WW1. Scarpaci, C., Parsons, E.C.M. and Lück, M. Recent advances in whalewatching research: 2006-2007. 17pp.
A study in Stellwagen Bank in Massachusetts Bay looked at the relationship between exposure to whalewatching vessels and calving success. There was no negative impact observed; indeed, calving rates and calf survival slightly increased in whales with more exposure to whalewatching vessels. It was noted that in this area, whales are exposed to regular ship traffic, so that whalewatching vessel exposure may not be as significant a factor as in some other places.
SC/59/WW23. Weinrich, M. and Corbelli, C. Whale-watching in southern New England does not affect humpback whale (Megaptera novaeangliae) calving rates or calf survival. 17pp.
In addition, numerous studies were discussed that looked at responses to whalewatching observed in specific locations worldwide. Responses included reduction of time spent foraging, increased disturbance with greater numbers of boats, short-range avoidance, and traveling away from the area. Those especially interested in such effects are urged to read the full Whalewatching subcommittee report. [DOWNLOAD (pdf)]
A subtle but significant issue arises in some areas, such as Puget Sound, where boat traffic has reached a saturation point: nearly all orcas are within 400m of a vessel all day long. This makes it difficult to assess the responses to specific interactions with boats, and increases the likelihood that any nearby, short-term response to boats will be repeated throughout the season, leading to cumulative negative impacts. Further, it is difficult to determine whether responses are triggered by noise or by the boats’ presence. Interestingly, the suggestion of providing some boat-free zones (exclusion zones) in order to provide some controls for exposure studies could itself be problematic at this point: such a noise-free zone may act more as a new experimental treatment, rather than a baseline control, since such noise-free zones are becoming increasingly rare. (In places where such exclusions have been established, whalewatching vessels generally abide by them, but private boaters routinely disrupted the “control” observations.)
Bain, D.E., Lusseau, D., Williams, R. and Smith, J.C. 2007a. Vessel traffic disrupts the foraging behaviour of southern resident killer whales (Orcinus spp.). Marine Ecology Progress Series. Submitted. 26pp.
Bain, D.E., Williams, R., Smith, J.C. and Lusseau, D. 2007b. Effects of vessels on behavior of individual southern resident killer whales (Orcinus sp.). 29pp.
Finally, plans are progressing for next year’s planned workshop to develop a global scale research design addressing whalewatching and its effects. The goal is to design a study that will be replicated at different sites, and to select appropriate sites where it will be carried out. This study will focus on: whether whalewatching can alter population biology parameters, whether whalewatching can act as an evolutionary selective force on targeted individuals and populations, and endeavour to detect the mechanisms involved in these impacts. While the practical and logistical challenges to mounting such a coordinated effort are clear, the sub-committee felt that there was a need to shift the way that we approach the issue of whalewatching disturbance. Ad-hoc studies of whalewatching impact assessment have been carried out for more than 20 years and yet we still do not have a solid grasp on the general principles governing the disturbance created by boat interactions with cetaceans and their consequences. Only a coordinated large-scale and long-term project will be able to get at this issue. Another member noted that this project presents a unique opportunity to more widely understand how anthropogenic activities disturb and impact the lives of cetaceans.
SC/59/WW17. Lusseau, D., Bejder, L., Carlson, C., Fortuna, C., Parsons, C., Robbins, J., Simmonds, M., Weinrich, M. and Williams, R. Workshop for strategic planning of large-scale whalewatching research. 3pp.