It has not been a great year for Risso's whereas in recent years they have been seen most months often in numbers both from the shore and from the ferry. I fear military exercises in the spring may have been responsible... The helicopters we saw here, off the Pembrokeshire coast from the Stena Europe in early April use anti submarine dipping technology. Basically they dangle sonar transmitters into the sea and emit low frequency sound. I am no expert but we do know naval anti submarine sonars can be devastating to submerged cetaceans as well as submarines.
As deep divers Risso's would be particularly vulnerable.
My concerns may be unsupported inasmuch we dont know where or if such weapons were deployed, but it would be odd to have a naval exercise that did not include anti submarine missions.
I realise that we need adequate defences against ever evolving weapons that may be used against us by regimes that care little for human like far less animals. None the less the time money and effort invested in potentially exterminating human beings either singly or en mass, and all the other life forms on this planet does seem illogical.
