European Cetacean Society Statement on Noise and Marine Mammals:
Final statement by the Council of the European Cetacean Society, based on
the
request of the ECS membership at the 2002 Annual Conference at Las Palmas de
Gran Canaria. The statement and more info on the ECS can be found at the ECS
web site.
Marine mammals are acoustically diverse and present wide variations not only
in ear anatomy, but also in hearing range and sensitivity. Cetacean middle
and
inner ears are structurally modified from those of terrestrial mammals in
ways that accommodate rapid pressure changes. The same adaptations may,
perhaps,
provide protective mechanisms that lessen the risk of injury from acoustic
impact, but no behavioural or psychometric studies are available to support
or
even address this issue.
Given the fact that marine mammals depend on sound for all aspects of their
life, there is no doubt that they are extremely vulnerable to man-made,
underwater noise. In light of an alarming recent increase in mortality
events, it is
becoming clear that man-made noise, at different intensity levels,
negatively
affects cetacean populations in important ways (17th European Cetacean
Society
Conference, Las Palmas de Gran Canaria, March 2003: “Marine Mammals and
Sound”). This includes, for example, the animals’ displacement, avoidance
reactions, collision with ships, stranding and death.
Evidence is particularly strong that high intensity active sonar, and
probably other loud noise sources, like those from shipping, gas
exploration, seismic
surveys, etc., cause lesions in acoustic organs which are severe enough to
be
lethal. The same sources may also produce behaviours that cause acute
lesions
which eventually lead the animals to strand and die (Active Sonar Workshop,
17th ECS Conference, March 2003).
The current scientific knowledge on the effects of noise on marine mammals
and their habitat is insufficient to understand the relationships of
frequencies, intensities, and duration of exposures that produce injury.
In the face of this uncertainty, the European Cetacean Society Council
considers that:
Research on the effects of man-made noise on marine mammals is urgently
needed and must be conducted to the highest standards of scientific and
public
credibility, avoiding all conflicts of interest;
Non-invasive mitigation measures must be developed and implemented;
In areas of cetacean concentration, the use of underwater powerful noise
sources should be limited until their short- and long-term effects on marine
mammals are understood and can be taken into consideration;
Objective parameters must be designed to assess the conservation of marine
biodiversity and to help implement national and European policies on marine
noise pollution.
