WHALES’ ACOUSTIC WORLD IS DISAPPEARING

graphic of ships polluting whale habitat with noiseIt’s been a long time between news alerts ! Apologies but the last few months have been hectic with the battle to stop PG&E carrying out months of seismic surveys destined to create havoc in the marine environment.

“Imagine a space ship is over your village and it’s sending explosions down to every 10 seconds, driving everybody crazy. The choice is you either leave or die. The acoustic world is 10% of what it should be. The whales social network is destroyed, their world seriously compromised, their immune and reproductive systems impacted by stress created by noise.” Dr. Chris Clark

  • A recent paper published in BioScience by leading experts in underwater noise spells out some of the impacts on marine mammals.
  • Every particle of factual evidence supports the contention that the higher mammalian vertebrates experience pain sensations at least as acute as our own.
  • Cetaceans are sentient beings with the capacity to suffer. They cannot lose consciousness.
  • Of some 80 species of extant cetaceans, audiograms are available for fewer than l0 species.
  • The impact of an acoustic source can be either on the hearing of a marine animal ( if the source is in the frequency band of efficient hearing for that animal) or ( at higher received levels) outside the hearing band (by direct trauma due to acceleration/displacement of tissues due to acoustic pressure fluctuations as an acoustic wave passes by or perhaps enhanced by resonance of cavities in the lungs, intestines or sinus cavities and the vestibular system.
  • In other words, what that sentence means is that the lungs, ears, intestines and sinus cavities can explode as a result of pressure waves.
  • Any reduction in hearing ability – whether by physical damage or masking of sounds – is likely to seriously compromise the viability of individuals and, potentially, populations..
  • According to the experts, there is a very limited understanding of the use of sound by marine mammals and similarly limited understanding of the complexity of ecosystems on which whales depend; their migratory routes; breeding grounds; population dynamics; population numbers; status of prey; status of habitat.
  • No attempts have been made to model the effects of noise on the habitat and ecosystem of marine mammals. Fish and other marine organisms respond to noise in both experimental systems and marine environment.
  • No studies have been undertaken to ascertain whether noise effects prey species in a way that will increase or decrease their availability to predators
  • Current mitigation measures do not take into account physiological and psychological stress.
    Provision for comparing the birth or breeding successes or even the intermediate term health of whales subjected to noise. These are basic issues.
  • Being cognizant of a smorgasbord of sonar experiments targeting millions of cetaceans over the next five years, the lack of any global data base which indicates current status , numbers and frequency of sonar experiments, deployment of military sonar; seismic activities etc, there can be no accurate assessment of the amount of noise being visited on the ocean environment.
  • A global data base on the number of super tankers and other noise creating ships etc. and their routes should be developed.

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