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Presently mid-frequency active sonar (MFA) is in widespread use and low frequency active sonar (LFA) is being implemented for use by the US and its allies. LFA sonar can generate one of the loudest sounds humans can make. On hearing sonar, whales may dive or rise deeply and rapidly. This can cause a form of decompression sickness, also known as the bends. Navigation can also be disturbed by other noise pollution such as ‘seismic exploration’ or ‘seismic testing’, which is used by the oil and gas industry to detect the presence of fossil fuels underwater.
It has been postulated that one of the biggest causes of whales beaching, is due to disorientation caused by man made sonar. In fact the sea is full of noise pollution as well as all manner of other pollution, that human's dump there. There's lots of scientific papers published on this topic and many point to sonar interference as the main cause of whales beaching.
With another mass stranding of 107 pilot whales on Monday 21st February on New Zealand’s South Island, with all perishing, there needs to be a focus on preventing as well as getting those beached whales back to sea. Mass strandings generally occur on gentle shelving beaches, and do not often occur on rocky shores or mud flats or in areas where sand is not accumulating unless the stranding occurs in backwater areas inside an inlet. It is known however that a whales sonar works well off sand. So what are the other possibilities: Perhaps it's just an evolutionary thing, they will eventually grow legs and breath air, but I digress... We are killing one of the most beautiful creatures in the ocean. Do I need to hit you in the face with a wet fish to make you understand?
Environmental campaign groups led by the Natural Resources Defense Council (NRCD) say whale strandings and deaths are associated with sonar blasts, which are also thought to damage the brains and ears of marine mammals.
Let's put it this way, if somebody came into your house with a jack hammer, would you want to stick around? There's no doubt that whales endure a deafening torment in areas of oil and gas exploration. Noise is even more detrimental to marine mammals than to terrestrial creatures, as hearing is their primary sense and because sound travels so well in water, the noise could be many kilometres away and still have a detrimental effect on the sea creature.
Despite this, the US congress passed a bill in 2004 that allowed the Navy to use sonar wherever and whenever they like. However US judge Florence-Marie Cooper in 2008 overturned the exemption. The injunction stipulates that all sonar be switched off if marine mammals are spotted within 2,012m. Bush then signed a waiver saying that the ruling would "undermine the Navy's ability to conduct realistic training exercises". That's pretty much where we are at now.
The correlation between stranding and Navy use of sonar has been well documented, despite the Navy often claiming it was not in the vicinity at the time of the strandings. Now some might say that analysis of long-term trends in strandings indicated an effect of sunspot cycle length and that whales have been stranding since the beginning of time. But there is no doubt that there are more strandings these days. It's known that incidences of strandings are higher in warmer periods, making a slight case for climate change effects, but the majority of evidence points towards sonar as the main culprit.
Many postmortem examinations reveal dehydration, starvation, and a multitude of bacterial, viral and parasitic infections in and around the head sinuses. This would indicate to me a dual effect of starvation due to not being able to locate prey because of sonar disturbance and infectious conditions due to a degradation of the whales habitat. It's no wonder the whales are killing themselves.
It's great that there has been some victory to save our endangered whales, but if things are allowed to continue the way they are going, the outlook for marine mammals is not good.
