Cetacean Strandings – a plea for honesty

Although I have previously written an article entitled “Do seismic surveys cause whales to strand?”, the recent passionate and vitriolic claims by eNGOs that strandings have been caused by seismic surveys, makes this topic worth re-visiting.  I make no apology for drawing the inspiration for my title from the publication by Bradshaw et al (2006) entitled “Mass Cetacean Strandings – a Plea for Empiricism”.  In that publication, Bradshaw et al stated “More specifically, the stranding-prone regions of the world such as southern Australia cannot be used to support the noise-pollution hypothesis because military and other sources of sonar noise pollution are relatively uncommon there”. Clearly, this statement would also apply to New Zealand, given the frequency of strandings there.

This statement was based on an empirical study by Evans et al (2005) entitled “Periodic variability in cetacean strandings: links to large-scale climate events” utilising data spanning 1920-2002 and 639 stranding events many of which occurred BEFORE marine seismic surveys were even invented and off coasts where few, if any, seismic surveys were carried out.

Why therefore do organisations such as OIL free SEAS_Kangaroo Island (OFSKI), Huffington Post writer Dr Reese Halter and Greenpeace NZ in conjunction with Oil Free Otago, continue to ignore scientists and the available observational data, such as that shown in the following photograph?

Humpback whale and seismic array

Humpback whale and operational seismic array

I would not presume to guess what their agenda is but here are a few examples of the way these organisations are misleading a caring and giving community with misinformation, which is plainly at odds with the available scientific and observational data.

1. On their Facebook page, along with lots of other very inaccurate propaganda, OFSKI claims that the sperm whale strandings on the East Coast of the Yorke Peninsula at Ardrossan were caused by seismic surveys approximately 700km away  with two peninsulas in the way. This is inconceivable given:

1a. Sperm whales vocalise at similar sound levels to seismic pulses – 236dB at 1m. Thus, what they hear themselves, or in their pod, from their own vocalisations, would be far louder than they would hear at even 100m from a seismic source. Note that if large whales were any closer that about 100m there would be a greater risk of collision than deafness, even though smaller more mobile whales (eg pilot whales) and dolphins are often seen riding the bow wave during seismic operations. It is inconceivable that any reasonable person could claim they are harmed by received sounds that are lower than those they emit themselves. Why does OFKSI and others insist on claiming such impacts?

1b. As a result of their loud vocalisations, it is not surprising to see many instances of sperm whales continuing to behave normally (dive, feed and rest) in fairly close proximity to operating seismic vessels in Australian waters and other areas around the world. For example, in a 2003 JNCC report entitled “The effects of seismic activity on marine mammals in UK waters, 1998-2000”, Stone concluded “Sperm whales showed no observable effects from these data (although this does not mean that there was no disturbance, as there may have been effects that were not able to be examined using these data).” If there were effects that could have led to strandings, as claimed by OFSKI, surely they would have been observable!

1c. Finally, sperm whale strandings in the presence of NO seismic surveys are not at all unusual (as mentioned in the above introduction). Why does OFSKI ignore such events? One of the most famous historical sperm whale stranding cases occurred on the Dutch coast in 1601 (yes, 1601 – long before seismic surveys were invented) and a very long way from sperm whale preferred habitat (a bit like Ardrossan?). This stranding is immortalised in an etching by Dutch artist Jan Saenredam. Thus, for OFSKI to claim that seismic surveys caused the Ardrossan mass stranding is a clear case of the observable data being ignored.

2. In an article in The Huffington Post entitled “Big Oil destroys the Great Australian Bight, Dr Reese Halter appears to come to the support of OFSKI but is clearly incorrect with the following assertions:

2a. Firstly, he claims “Big Oil Destroys the Great Australian Bight”. How come over 150,000km of seismic traverse have been acquired and 12 wells have been drilled in the area since the 1970’s and there have been negligible impacts from this activity? This does not sound like “destroying” to any reasonable person;

2b. Secondly, Dr Halter makes much of majestic blue whales being in danger from seismic surveys but, despite very close monitoring over more than a decade during seismic surveys conducted along the southern margins of Australia, it is obvious that they are not in the dire danger that he and others claim.  If Dr Halter were correct the impacts would have been obvious.  In addition, some of these monitoring reports are on the public record, so Dr Halter is clearly ignoring and distorting the facts.

2c. Thirdly, on the topic of distorting the facts, his claim that the melon-headed whale stranding in Madagascar in 2008 was caused by a seismic survey is totally false. In an IWC report on the incident, the Independent Scientific Review Panel (ISRP) concluded that they “systematically excluded or deemed highly unlikely nearly all potential reasons for the animals leaving their typical pelagic habitat and entering the Loza Lagoon (an extremely atypical area for this species). This included the use of seismic airguns in an offshore seismic survey several days after the whales were already in the lagoon system, which was originally speculated to have played some role but in the view of the ISRP clearly did not.”  Dr Halter has ignored at least two very important pieces of information – the seismic survey commenced several days AFTER the whales were already in the lagoon system AND the panel concluded that the seismic survey CLEARLY DID NOT cause the stranding.

3. Finally, we have Greenpeace NZ and its supporters such as Rosemary Penwarden of Oil free Otago.  The constant “noise” from this group is typified by an extremely misleading opinion piece in the Otago Daily Times on Friday 23 January entitled “Oil search puts dolphins at risk”.  There is very little, if any, valid evidence in the emotive but inaccurate claims by Ms Penwarden (and Greenpeace). For example:

3a. Ms Penwarden “links seismic testing for oil and gas with serious harm to whales and dolphins”. How can this be so if no documented cases of harm to cetaceans exist in over 40 years of seismic surveying (note the correct term “surveying”) using compressed air as the seismic source?

3b. Her description of seismic acquisition is so unrepresentative, using terms such as “detonators” and “blasting,” that it is surely meant to mislead a caring and giving community. “Velcro” has done a good job of presenting a factual description of seismic surveying in an online comment rebutting her article so I will not repeat what he/she says.  In addition, I’d like to counter Ms Penwarden’s statement that seismic arrays “reach about 260 decibels (dB) on a logarithmic scale on which it is known that anything above 170 dB disturbs marine organisms.” as being clearly incorrect.  Firstly, she has used a theoretical value (of 260dB) for the loudness of a seismic array. This would only be achieved if all the 20-30 elements (compressed air cylinders, commonly called “airguns”) in the array occupied the same location. This is clearly impossible!  The actual decibel level within 1m of any part of the array would be between 220 and 240dB, depending on the type of array.  Secondly, given sperm whales and bottlenose dolphins vocalise at 236dB and 225dB respectively (a lot more than 170dB), how can Ms Penwarden claim they would be disturbed, letalone “seriously harmed” as mentioned elsewhere in her opinion piece? After all, these cetaceans (or others in their pod) would receive vocalised sounds at close to their emitted levels whereas any received levels from the seismic array would be significantly lower than their own vocalisations.

3c. She perpetuates the inaccurate claim that the mass stranding of the melon headed whales in Madagascar was caused by a seismic survey. As mentioned above, the ISRP concluded the seismic survey “CLEARLY DID NOT” cause the stranding.

3d. Finally, she and Greenpeace claim that the unfortunate stranding of 3 Gray’s beaked whales on Whatipu Beach near Auckland last week was caused by a seismic survey, which I understand was 200km away. Given that strandings in NZ are very common and there is NO correlation between stranding events and seismic surveys, why are they ignoring the readily observable facts? How do they explain strandings that occurred in the absence of seismic surveys, either before seismic surveys were invented or in seasons when seismic surveys did not occur?  Given the frequency of strandings there will be coincidences but it is disingenuous to exploit these unfortunate incidents for their own ulterior motives.

In summary, these organisations surely have a responsibility to ensure that their claims are factually based and verifiable? “Truth in campaigning” should apply to lobby groups in the same way “truth in advertising/reporting” applies to businesses. Unfortunately, at best, these lobby groups are either displaying a high level of ignorance or, at worse, they have deliberately chosen not to display the same high level of honesty that they themselves demand from others.

The public deserves an open, transparent and honest debate on the unfortunate issue of cetacean strandings, but are misinformed by the likes of Greenpeace, Oil free Otago, OFSKI and Huffington Post (Dr Reese Halter).



  1. I agree 100% percent with the above mostly because the animals have the freedom to move away from a source of painful noise long before their ears and sinuses are blown out. The source of injury must catch the whales by surprise and cause injury before they have a chance to flee. There are three things that can do this: (1) a shallow undersea earthquake, (2) a volcanic explosion, (3) an explosion set off by man, and (4) the violent impact of a heavenly body with the surface of the ocean near whales. The first two are the most likely; however, the navy, oil industry, and the scientists they support have never in the past or will they today, invested natural seafloor upheavals. The question is why not?

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