Dolphins know where to get a feed
IF you were a Northern Rivers bottlenose dolphin, the most popular place to live would be the Clarence River, according to new research.
Christine Fury, a researcher with Southern Cross University's Whale Research Centre, has been studying local estuarine dolphin populations for three years and has uncovered some fascinating facts about
our warm-blooded mammalian cousins.
The Clarence River, which runs through Yamba, Maclean and Grafton, is the number one dolphin housing option, while the Richmond River, which runs through Ballina, Wardell and Coraki, is the second most popular home-base choice, Christine found.
Although dolphins are widely studied in marine habitats, information on estuarine populations is very limited.
Christine's study, published today in the CSIRO journal Marine and Freshwater Research, provides the first published data on Indo-Pacific bottlenose dolphins in Australian estuaries.
Christine estimates that about 71 dolphins utilise the Clarence River compared to about 34 dolphins in the Richmond River.
Differences in home-place 'loyalty' (or site fidelity) were observed between the estuaries with 60 per cent and 37 per cent of identified dolphins determined as residents, 26 per cent and 21 per cent as occasional visitors, and 14 per cent and 42 per cent as transients, for the Clarence River and Richmond River respectively.
“The Clarence River is the most popular because it is the largest estuarine river system in NSW and therefore has a greater volume of water. It also has less urban and agricultural development. Both these factors mean the water quality is better,” Christine said.
“Dolphins are the top predators in the river systems, so the cleaner the water, the more fish in the river and the better the ability to sustain a bigger dolphin population.”