Two days ago a pod of nine orcas was found stranded on a rocky beach in southern New Zealand. Researchers are attempting to find out what may have caused the tragedy, but after being out of water for some time the condition of the carcasses will make a clear diagnosis difficult. That the animals were healthy before stranding rules out a number of causes, such as starvation or chronic illness. Having all stranded at the same time would indicate some sudden catastrophe.
There may be an association with a seismic survey currently being conducted within a 150 miles of the stranding. Although there is not much evidence that seismic airguns have caused many catastrophic whale strandings, there may be new technologies being used that could be at cause. Recently a seismic survey was implicated in the stranding of 100 melon-headed whales in Madagascar, although it was not the airguns; rather it was a multi-beam sonar seafloor profiler that was at cause.
Fifteen years ago it was the US Navy’s use of mid-frequency sonar that was causing lots of strandings; alerting the public that ocean noise pollution was a growing problem. Whether from mitigation practices, changes in technologies, animal habituation, or just plain luck, the US Navy-associated strandings have diminished appreciably. But now marine extractive industries such as fossil fuel and seafloor minerals mining operations are introducing all manner of new technologies and new noises into the sea.
The added complication here is that unlike the US Navy, which is somewhat subject to US environmental laws, international corporations are not so easily constrained. As these industries set out into deeper waters and farther fields the impacts of their practices will be more difficult to monitor – or to mitigate.