Whales washed ashore had the bends

Deep- diving whales washed ashore have suffered from the bends, say marine experts.

The Ministry of Defence (MoD) is now being asked if naval sonar used in the recent Nato war games, Joint Warrior, was responsible.

It is thought the sonar waves can frighten deep- diving whales, forcing them to surface too quickly and leading to symptoms similar to decompress ion sickness, also known as the bends, in humans.

Investigators from the Scottish Marine Animal Strandings Scheme said the recent spate of five whale strandings was unusual.

A report stated: “Given how sensitive beaked whales are to underwater noise, specifically naval sonar, we have to consider that as a possible cause for two strandings.

“We are, therefore, in the process of trying to find data on sources of noise in this region, including putting a request for activity logs to the MoD following the recent Joint Warrior naval exercises.

“The last three cases were northern bottlenose whale strandings; one in the Western Isles and two in the Clyde sea lochs.

“All these cases were reasonably decomposed which limits what diagnostics we can run, and unfortunately pretty much rules out any assessment of noise overexposure.”

Most of the Joint Warrior training takes place around Scotland’s coasts and includes live- firing at ranges such as Cape Wrath in Sutherland.

A spokeswoman for the MoD said the Navy does all it can to ensure sonar is not damaging marine life.

She said: “The MoD takes its environmental responsibilities very seriously.”