Dolphin scientist Mike Bossley will speak at the Scottish Seabird Centre tonight. I have the pleasure of introducing him and talking about our joint Whale and Dolphin Conservation campaign to make “Homes for Whales & Dolphins”. One thing I want to ask him about is the unprecedented string of dolphin deaths in the Gulf St Vincent off Adelaide, South Australia, where he lives and works with dolphins every day.

Over the past couple months, the news is that at least 24 bottlenose dolphins have died — almost all of them juveniles. At the same time, thousands of inshore reef fish have washed up on local beaches. Local waters have been up to 5 degrees centigrade above normal for the time of the year.

The dead dolphins are from the wider gulf area around Adelaide and not from the core population that Mike studies and has helped to protect in the Port River estuary as part of the Adelaide Dolphin Sanctuary, an urban marine protected area.

Researchers have so far been unable to determine cause of death. Laboratory tests of the dead dolphins’ tissues are in process. At this stage the most widely accepted theory of what has caused the deaths is a toxic dinoflagellate bloom (ie “red tide”) but no such bloom has been observed to date. If this “mass mortality event” does turn out to be the result of a dinoflagellate bloom it will be the first record of such impacting on dolphins in this part of the world and may be a consequence of climate change.

My book Seasons of the Whale talked about mass mortality events off the US and Canadian east coast some years ago — about 15 humpback whales died due to mackerel that had consumed dinoflagellates as part of a red tide. There were more 750 dolphin deaths but they were more likely due to pollution events. Recently I have re-issued this book as an ebook, with a new epilogue to talk the aftermath. Some surprises… The book is available for instant download from: Amazon.com: http://amzn.to/XBIFOY or Amazon.co.uk: http://amzn.to/10iiP0W as well as from other Amazon sites.

                                                                                                        — © Erich Hoyt 2013