| Sonar does affect whales
Whales subjected to military sonar will neither dive nor feed, according to an unpublished 2007 report from the UK military. The UK military report details observations of whale activity during Operation Anglo-Saxon 06, a submarine war-games exercise in 2006. Produced for the UK’s Defence Science and Technology Laboratory, it states the results are “potentially very significant”.
Several details in the 2007 report, such as the location of the exercise and its participants, have been removed under section 27 of the UK’s freedom of information legislation, which governs information that might prejudice international relations. However, it is clear that a number of countries took part in the exercises, which involved at least four warships hunting two nuclear-powered submarines. Although the location of Operation Anglo-Saxon 06 has been removed from the report, the pattern of hydrophones shown in one diagram matches that in the US Navy’s AUTEC range in the Bahamas.
The study used an array of hydrophones to listen for whale sounds during the war games.
Across the course of the exercise, the number of whale recordings dropped from over 200 to less than 50. “Beaked whale species ... appear to cease vocalising and foraging for food in the area around active sonar transmissions,” concludes the report. It notes, “Since these animals feed at depth, this could have the effect of preventing a beaked whale from feeding over the course of the trial and could lead to second or third order effects on the animal and population as a whole.” The report references a second military document from 2005 which explains that these second- and third-order effects could include starvation and then death, depending on the severity of the sonar's initial effect on the whales.
A spokesperson for the UK’s Ministry of Defence (MoD) said in a statement: “Active sonar releases energy into the ocean, and there is evidence to suggest that this may have an effect on marine mammals. However, the precise scientific effects are not clear, thus the MoD has adopted a precautionary approach to mitigate effects on the marine environment. Environmental Impact Assessments are mandatory prior to the use of military sonar, and the ability to predict and detect marine life continues to be developed in order to minimise any perceived threats to marine life.”
Research from scientists is also beginning to come to the same conclusions as the anecdotal evidence detailed in the military report, showing that whale behaviour is modified by sonar, even if it is not yet possible to say that behavioural changes equate to actual harm.
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