AcousticEcology.org Special Report
International Whaling Commission
Excerpts from Annex K of the Scientific Committee Report, from the Standing Working Group on Environmental Concerns.
This 19 page Word doc contains the full text of:
Section 8.5 - covering anthropogenic noise
Appendix 1 - 2005 State of the Cetacean Environment Report (SOCER) section on noise summarizing research and press reports for this year
Appendix 3 - planning for a workshop on the impacts of seismic surveys:
[DOWNLOAD IWC57 REPORT EXCERPTS (doc)]
Following on last summer's significant work on the effects of anthropogenic noise (see AE.org Special Report), which included calls for more transparency from the oil and gas industry, and deeper consideration of the effects of military sonars, the International Whaling Commission's Standing Working Group on Environmental Concerns once again addressed noise issues in 2005.
Among the issues discussed and findings presented this year:
Research on non-marine animals that may be relevant: well-fed birds showed more response to human disturbance, while animals with fewer food resources did not; the implication is that weaker animals may not move away from elevated sound levels, and that we should not look only at behavioral response as a measure of vulnerability. Juvenile rats raised in a noisy environment displayed retarded development in auditory centers of the brain.
Noted several new "atypical stranding events" (stranding at approximately the same time but not in close proximity) coincidental to military sonar exercises. While the mechanism causing the strandings is still unclear, "it is increasingly apparent that tissue damage and strandings may be induced at lower sound levels than those that induce auditory damage (ie, lower than those currently being used as an acceptible level for management guidance)." Beaked whales found dead onshore during the "Majestic Eagle" NATO exercises near the Canary Islands in July 2004 almost certainly died at sea; "this increases the concern that other animals affected during similar events are also dying at sea but are not being discovered and examined."
Because of this, "It is no longer realistic to limit mitigation methods to consideration of auditory impacts to within a small radius of the sound source." An Office of Naval Research study (Barlow and Gisiner, 2004) suggests that on-ship monitoring for beaked whales is likely to detect less than 2% of beaked whales, dropping to zero by about 1km from the trackline of the ship.
It was suggested that Marine Protected Areas have a good potential to address impacts from noise; noted was the World Conservation Union (IUCN) request to the World Commission on Protected Areas to consider noise as a factor in MPA designation and management.
The Standing Working Group strongly encouraged producers of high intensity noise (sonar and seismic operators) to share information on noise soruce characteristics and work with scientists to investigate the impacts of these activities. A workshop convened by the World Conservation Society in June 2005, considering impacts and mitigation of offshore oil activities along the West African coast, was endorsed by the SWG; such cooperation between industry, environmental groups, and scientists is important, and is encouraged elsewhere. Indeed, the Joint Industry Project (JIP) is initiating a series of workshops and meetings on Sound and Marine Life, the first of which is scheduled for September 2005.
A review of traditional and more modern fishing and whaling techniques using sound to herd or tire the target species was presented.
Responding to increasing concern from researchers, as well as increasing activity by industry to study the noise impacts of their operations, a pre-meeting workshop on Seismic Surveys and their Potential Impacts on Cetaceans is being planned for May 2006, just prior to IWC58. Sessions are scheduled on Review of Seismic Surveys and Potential Impacts, Case Studies, Mitigation and Monitoring, and Breakout/Discussions. Presenters will include Chris Clark, Jack Caldwell, John Hildebrand, Dave Weller, Rob McCauley, and Doug Nowacek.
For more details on this year's IWC proceedings concerning noise, see this 19 page Word doc:
[DOWNLOAD IWC57 REPORT EXCERPTS (doc)]
Research Summaries: Papers of Special Note
Is the diversity of cetaceans in Brazil reduced by the intensification of the seismic surveys? (Cristiano Leite Parente & Maria Elisabeth de Araújo)
Using a rather coarse method, this paper looked at records of cetacean species diversity in Brazilian waters between 1999 and 2003, alongside the number of seismic surveys taking place during those years. The two years with the highest concentration of surveys (mean of 10-16 per month) correlated with the years of lowest species diversity. As survy numbers fell in later years (due to a combination of increased environmental oversight and the wealth of data obtained in the peak years), species diversity returned to previous levels. The data used was not precise enough to show a causal relationship, though the authors note that no such other factor appears in the scientific literature. The authors suggest that this study shows the potential for species diversity to be a useful measure of the impacts of seismic surveys, and encourage the use of abundance and distribution studies that are more closely tied to the survey areas; they also propose a limit of 6 simultaneous surveys, reflecting the lower level of activity during years of higher species abundance.
Hunting cetaceans with sounds: a worldwide review (Robert L. Brownell, Jr., Douglas P. Nowacek, and Katherine Ralls)
An interesting historical overview of traditional fishing practices worldwide that relied on herding cetaceans using sound; also includes some herding applications of a British anti-submarine system developed during WWII. The authors suggest that "the widespread success of drive fisheries world-wide shows that many species of small cetaceans have strong avoidance responses to relatively low-intensity sounds." They make special note of the tendency for cetaceans frightened in this way to enter shallow waters and begin to mill about; this behavior can lead to a beaching event.