Voices of the Sea
Sometimes I think we are mad, studying dolphins in the windy blowy gusty west coast of Scotland. But we’ve not completely lost our marbles! Yes, we spend countless hours sitting on headlands waiting for the sea mist to burn off, for the rain to stop, for the white caps to subside as the wind drops OR for a bit more wind to get rid of the midgies (!), but we also have a Plan B…
.. And as we’ve had a few windy days, we’re going to tell you about it!
With the assistance of a few helpful fishermen and the Stornoway Scottish Natural Heritage office, we have deployed a number of acoustic devices off the coast from the most northerly tip of Lewis at the Butt down to Kebbock Head just south of Stornoway (the capital of the Western Isles). These ingenious light-weight devices are called PODs (originally designed as POrpoise Detectors, but now very capable of detecting dolphins too). PODs are better than field researchers in that they are not weather dependent and they can collect data for 24 hours a day (unlike us!) Luckily they can’t take photo-identifications, and our batteries don’t run out, so we still have a role!
PODs are fully automated, static, passive acoustic monitoring systems that detect porpoises and dolphins by recognising the echo-location clicks the animals make to detect their dinner, find their way around and interact with each other (www.chelonia.co.uk). The PODs can tell us which areas porpoises and dolphins favour.
Harbour porpoises vocalise at very high frequencies and their foraging clicks are easy to understand on our PODs. Whilst dolphins are also typically vocal animals, the different species are very difficult to distinguish – and so far since we arrived here on the Isle of Lewis we have seen common dolphins, bottlenose dolphins and Risso’s. There have also been sightings of orcas in the Minch, but not in our patch - yet!
Minke whales are a different kettle of fish – so to speak! Their vocalisations remain little understood. It’s most likely that they are communicating when they are mating elsewhere over the winter, but we don’t know if or how much they communicate when foraging in Scottish waters over the summer months. So we remain dependent on our eyes (and sometimes ears - pphff!) to find Scotland’s most coastal visitors.
Before we leave, we will retrieve our PODs and hope that, after a summer spent bobbing beneath the waves recording the vocalisations of the dolphins, they will help us to unravel which are the favoured habitats of the dolphins and porpoises – which can ultimately lead to better protection.
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But kudos to the people who did their best to save him.