The Swan River running through Perth is home to around 25 bottlenose dolphins. Although it is a much loved icon of the river, this dolphin community is very fragile due to its small population size. In 2009, the Swan River Trust’s River Guardians program launched a new project called “Dolphin Watch”, aimed at improving our understanding of dolphin ecology and assisting conservation efforts. And on Tuesday night, Dolphin Watch gained three new volunteers in the form of me, Phil and Janelle!
Initial research conducted in 2002 provided the first information regarding dolphin numbers and movements in the Swan River. Dolphin Watch is a community project developed in collaboration with Dr Hugh Finn from Murdoch University and Dr Chandra Salgado from Curtin University. By training members of the public to collect scientific data on opportunistic dolphin sightings, researchers are obtaining valuable data regarding dolphin movements, habitat use, and information on behaviour and feeding in the Swan River.
- Dolphin Watch Monitoring Map
Phil, Janelle and I attended a Dolphin Watch training night on Tuesday evening at the Perth Zoo. The project currently has around 104 volunteers, and on Tuesday a further 80+ people signed up! Dr Hugh Finn kicked off the meeting with a brief summary of what is already known about the Swan River dolphins. There is a community of about 25 ‘resident’ dolphins who use the river on a near-daily basis; however, coastal dolphins also occasionally venture into the lower reaches of the river. Of the resident population, there are several adult females with dependent calves, one or two ‘alliances’ of tightly bonded adult males, and a large group of sociable youngsters. Since the whole population is dependent on just a handful of females, they are very vulnerable to environmental stressors such as pressure from habitat loss, decreasing prey, pollution, entanglement, or disturbance from human activities. In 2009 six of the Swan River dolphins died, sparking wide-spread concern for the dolphins and the health of the river system.
- Two Swan River dolphins (Photo Credit: Rachel Hutton)
River Guardians manager Marnie Giroud explained how to fill in the data sheets. She explained how to record the time, date and location of each dolphin sighting; record volunteer effort in terms of time spent looking for dolphins; identification of individual dolphins or the presence of calves; and the different behaviours displayed by dolphins. An important part of the training is learning how to observe the dolphins without disturbing them. Observations from boats allow close-up monitoring of the dolphins, but the presence of a vessel may alter their behaviour. Shore-based observations are ideal, as the dolphins are unaware of the presence of observers allowing their natural behaviour to be recorded without fear of bias.
Although the three of us are already pretty familiar with cetacean data collection, it’s always interesting to learn a bit more about different populations of animals and meet the people studying them. It was fantastic seeing such a great turnout from the local community. Without public involvement this kind of data collection would be at best very expensive and at worst nigh on impossible. Volunteers make a valuable contribution to dolphin research in the Swan River and, along with other initiatives to improve the quality of the river system, conservation of this small dolphin community should be possible. We can’t wait to get started!
Links:
Caledonian Explorer 