The snubfin dolphin appears to smile from its smooth, round head, like an old friend who’s lost his hair but still has an abundance of happiness to share.
Of course, that’s reading a lot from the unusual – for a dolphin – looks of the snubfin. It’s a marine mammal and smiling isn’t one of its tricks. That’s just the way it is, but those looks do make them endearing to humans.
The snubfin is found only in Australia’s tropical north and probably in the southern areas of the island of New Guinea and was only recognised as a separate species in 2005. Before that everyone thought it was a type of river dolphin found in south-east Asia.
Little is known about them.
Alex Brown, a a doctoral candidate at Murdoch University in Western Australia, says the snubfin’s shy behaviour, coupled with the inaccessibility of much of their habitat, makes them difficult to study.
He’s working on estimating the population size now after several trips to look at different groups of the dolphins along the coast in the north west.
The general scientific thinking is that there are well below 10,000 mature snubfin dolphins. By numbers alone, this would place them in a vulnerable classification.
However, we just don’t know enough about the dolphins to confirm this reasoning or show evidence of a decline.
But Brown’s research, funded by the federal government’s Australian Marine Mammal Centre, will be able to give more precise estimates of several local populations in Western Australia.
Those findings and earlier work, will make it easier to work out how to protect them.
Only a few have been dissected, those which have washed up dead or died in anti-shark nets on the east coast.
From that we know they eat small fish, squid and small Crustacea such as prawns.
The appearance of a neck wrinkle (and perhaps the illusion of a chin) is due to the fact that only the first two vertebrae are fused together rather than the first four as found in most dolphins. This makes the head more flexible.
Add to that the absence of a typical dolphin beak and you have something which looks a little human-like.
As if that wasn’t unusual enough, the dolphin is also known to spit jets of water up to two metres across the surface of the water. This strange behaviour is often followed by the leap of a confused fish, and it is thought to be used to disorientate their prey during pursuit.
Alex Brown and his colleagues at Murdoch University estimated a population of around 130 snubfins in the waters off Broome.
“At over 130 animals, this is the largest reported abundance of snubfin dolphins in Australia to date and should be considered of regional and, indeed, national significance.”
Being reliant upon shallow water close to the coast, the snubfin is sensitive to human activity. Interactions with commercial fisheries poses a threat and so too does physical change and acoustic disturbance in the coastal zone. Brown says any development in the north west should take this into consideration.
Large-scale industrial development is occurring across north western Australia, resulting in modification to coastal habitats through dredging, construction and increased shipping.
“With so little data on coastal dolphins in this region, the potential impact of these developments remains unknown,” says Brown.
Murdoch University’s Cetacean Research Unit has more information here.
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