SA Senator Penny Wright’s recent speech and motion in the Senate obviously did not make much of an impression. Only 2 senators voted for the motion – Sarah Hanson-Young and Penny Wright herself.
If we take just one section of her speech (which is presented as facts and upon which her entire speech and motion is based), the interested reader will soon understand why only one other senator (her Green colleague!) sided with her. This is what the Senator said about seismic surveys:
The science is also clear that seismic testing poses a significant threat to marine life in the area. During seismic surveys, a low-frequency, high-intensity sound pulse is emitted every few seconds by an array of guns, which operate 24 hours a day over a period of months. The sound pulses are 100,000 times louder than a jet engine. Imagine, if you can, having a jackhammer going in your kitchen 24 hours a day, seven days a week for months on end. Seismic testing has been shown to change the breeding, feeding and migratory patterns of whales. That is of particular concern in this area because it is a critical feeding area for blue, sperm, beaked and fin whales.
Anyone who is aware of the science and facts about seismic surveys and marine life and it is great to know that the other senators were, will know that this paragraph is full of incorrect statements by the Senator which are purported to be facts. For example:
1. Senator Wright stated “The science is also clear that seismic testing poses a significant threat to marine life in the area“. If anything is clear, it is that previous seismic surveys in the Great Australian Bight and, in particular, a 2003 survey in the very same area, have NOT had the impacts she claims. Unfortunately, most scientific papers on this issue expose caged animals, that cannot display the behavioural responses they would display in the wild, to acoustic sources that are not representative of commercial arrays in the natural environment. Following extensive and detailed analysis to arrive at often very subtle effects, researchers then suggest that seismic surveys “could”, “may” or “potentially” have significant impacts on marine life.
2. She went on to say “….sound pulse is emitted every few seconds by an array of guns, which operate 24 hours a day over a period of months.” How and why does “approximately every 10 seconds” become “every few seconds”? This is blatant misinformation. Also, it would be impossible for the source array to be active 24 hours per day over a period of months due to the fact that it would be powered down for line changes, standby due to weather, third party shipping, whales, etc and, of course, technical downtime and crew changes.
3. Furthermore the Senator said “The sound pulses are 100,000 times louder than a jet engine.” This is totally incorrect and simply propagates a very inaccurate claim by a USA environmental group. This group conveniently “overlooked” the scientific fact that the comparison was between a jet engine at 100ft (approx 30m) and the theoretical sound level of a seismic array at 1m. I say “theoretical” because it is impossible to get to within 1m of all the individual elements of a seismic array with dimensions of approximately 15m x 10m. The USA environmental group also “forgot” about the approx 62dB difference in values between the same sound levels in air as in water. That is, 180dB in air is 242dB in water. Given the sound of a jet plane taking off (in air, of course!) is 180dB and the sound of a typical array used in Australian waters is theoretically about 242dB, this means the sound level of a seismic pulse is actually SIMILAR to a jet taking off – not 100,000 times as claimed by the Senator.
4. The Senator’s analogy “Imagine, if you can, having a jackhammer going in your kitchen 24 hours a day, seven days a week for months on end.” is totally incorrect. Firstly, the seismic vessel moves and secondly the attenuation in the near-field is very rapid. Another article on this website shows the actual measurements of sound levels at a stationary acoustic recorder over a 5 day period. This “sound picture” shows that the Senator’s claims are incorrect.
5. The Senator then added “Seismic testing has been shown to change the breeding, feeding and migratory patterns of whales.” The population of humpback whales on the West Coast of Australia has grown at a rate close to biological maximum over the last 40 years. This growth rate is similar to that on the East Coast. This surely means that, given the level of seismic activity on the NW Shelf during this same period (and the development of the oil and gas resources that have been so important to Australia’s financial wellbeing), seismic surveys have had NO impact on the breeding and migratory patterns of humpback whales. Ironically, humpback whales feed in Antarctic waters during the summer months and are obviously not disturbed by the sounds of calving/colliding icebergs which are similar in intensity and frequency to seismic sounds.
That just leaves her final sentence in this paragraph which, of course, is based on the misinformation that went before it and has been rebutted in points 1-5 above: “That is of particular concern in this area because it is a critical feeding area for blue, sperm, beaked and fin whales.”
Even though the above species are unlikely to be impacted by seismic surveys (they have not been adversely impacted during previous surveys), it is interesting to note that Bight Petroleum have nevertheless considered this possibility and incorporated very comprehensive management measures into their survey application. The interested reader can find these management measures in Bight Petroleum’s referral (EPBC 2013/6770) and the public documents that Bight Petroleum has been required to make available on its website as part of the ‘controlled action’ decision by the former Minister for the Environment.