Murdoch uncovers dolphin-climate change link

By Graeme Paton   Perth’s playful bottlenose dolphins are being threatened by extreme climate events, says a new study by Murdoch University. The research project, by Dr. Kate Sprogis of the Murdoch University Cetecean Research Unit, is the first of its kind to help measure the impact global climate change is having on dolphins in Bunbury. The study examined a number of factors that affected Bunbury bottlenose populations, with unusually high El Niño measured as causing a significant decline in their population. The in-field research, which took place over six years, from 2007-2013 involved measuring dolphin populations using “spotting”, which identified dolphins by their unique dorsal fin markings. The research co-incided with the 2009 El Niño, which warmed currents in the Indian Ocean that intensified trade winds called “the Leeuwin Current”, impacting living conditions for the local dolphin populations. This included factors such as availability of food, sea surface temperature, rainfall and ocean salinity. Dr. Sprogis told The Bounce this week: “Dolphins, like humans, live in communities and if their livelihood is under threat it can be hard for them to find refuge in a new community.”   While El Niño is by definition irregular, Dr. Sprogis warns that “if global water temperatures continue to rise at current estimated levels, the effect of El Niño will become more intense.” Statistics from Perth’s Bureau of Meteorology show that since Dr. Sprogis’ research ended in 2013, global ocean temperatures have increased and the 2015-2016 El Niño was one of the strongest on record. BOM has associated El Niño in Australia with severe weather and environmental effects including droughts and bleaching of the Great Barrier Reef. Dr. Sprogis hopes that her research will inspire collaborations between researchers to help shine a light on an issue that is affecting WA’s much-loved beach and river dwellers. “With the effect of climate change happening faster than [scientists] had originally estimated, I hope we conduct more research with Hawaii, California and in the eastern States so we can be more aware of this problem facing marine life.” Dr. Sprogis said.