As an animal lover and also an ex-Sonar Operator, I have feelings on both sides of the fence on this story. However, at the moment, the accusation is purely theory - there are a number of possible explanations:
Possible causes of the dolphin tragedy
- They committed suicide
- Sonar signals scrambled the dolphins' echo-location system
- Killer whales scared the dolphin pod into the shallows
- An explosion frightened them into shallow water
- They fled to the cost to escape predation by a killer whale
- They were swimming to the aid of an injured pod mate
- They were chasing fish feeding on algae thriving in the warm water
Not having seen the actual "report" I can't be sure how objectively this issue was investigated or whether it was always assumed that Naval operations were involved - talking about helicopter overflights seems to be scraping the barrel for reasons to blame the RN!
If sonar transmissions were the cause of strandings, how come there were none reported back in the 1960s through to the 80s when there were far more frigates and destroyers based at Devonport and exercising or doing trials in the same areas?
Personally, I would wonder if the fishing industry could do with a bit more scrutiny - there is plenty of evidence that dolphins get drowned in their nets and for every one that is caught there would be others that survive with a distinct aversion to fishermen in the future.
Having read it I do have some concerns about objectivity as for instance the Executive summary gives a list of possible causes that were excluded then launches straight into the fact that there was a naval exercise several days beforehand without any preamble. The detailed description of the methodology gives no further explanation of why they didn't follow up on fishing activity. I have e-mailed the main author, who has done a number of research papers on sonar affecting ceteceans to ask why this wasn't investigated too and wait with interest for a response!