Is this a new 'Great Whale'?
October 28, 2010
You'd hardly think that in 2010, some of the biggest animals that ever existed, were still left to be discovered. We're not talking about dinosaurs but modern-day whales.
This month on Australia's north west shelf, I was lucky enough to guide an enthusiastic team of amateur birders and wildlife enthusiasts into what I believe is one of the richest marine areas of the world. Amongst the eight species of cetacean we saw on thie Peregrine Bird Tours trip (which also included Australia's only endemic dolphin, Australian Snubfin Dolphin ) were a number of whales different to anything I've ever seen before.
Between 10-14m long and with newborn calves, these whales are like a cross between the rather subtly marked Bryde's Whales and the heavily marked Fin Whales. Of course, they were too small and the wrong shape for Fin Whales but they had that white lower jaw only on the right hand side, which until recently was a unique Fin Whale character - until that is, Ben Kahn found odd whales in Indonesia with this feature ... and in 2003, Japanese whalers described "Omura's Whale", as a 'pygmy' form of Bryde's.
Our whales were feeding voraciously over deep reefs and shoals in only about 50m of water, with a supporting cast of Wilson's Storm Petrels and Spotted Sea-snakes.
On the face of it, this would seem to be a new whale for Australia and quite possibly an undescribed 'taxon' - that is, a type of whale that is unknown ... maybe a species or a subspecies.
What is for certain is that this animal occurs in an area undergoing rapid expansion for oil and gas and where last years well-head blow-out indundated tens of thousands of square kilometres of ocean with oil. This was a lesser-known incident over-shadowed by the BP disaster in the Gulf of Mexico and was surveyed by WWF .
What's faintly amusing about this story is that the discovery was made by a group of sea-going 'grey nomads' (as they are referred to in Australia). This is despite investment into 'research' on the northwest shelf by industry with a commercial interest in the area. While I mention it, the group also found a population of a new seabird for Australia: Arabian Shearwater . It just goes to show, how important communities can be in helping understand and manage our planet's ecosystem.
For further information, contact Simon Mustoe by leaving a comment on any of the images.
[Approximate location only shown]
The sightings were discontinuously distributed along a transect about 40 miles long, in water varying in depth between 50-70m. The whales were always in association with strong surface patterning, surface algal growth, some seabirds and sea snakes. This suggested that their distribution was determined to some extent by the presence of sub-surface reefs, currents and upwelling. The animals were not seen singly. Up to three or four animals would be seen together and at least two were with small calves.
Behaviour was fairly consistent for all pods encountered. They would break the surface rapidly for short breaths, diving for periods of 2-5 minutes, presumably while feeding. Sometimes fluke-prints would be visible every half a minute or so. About every 20 minutes, they would surface strongly two to three times, when the blow would become audible and visible. The rostrum often broke the surface, permitting clear views of the splashguards, lower jaw, rostral ridges, back and dorsal fin.
The animals were clearly far too large and wrongly-marked for Minke Whales but too small for Fin Whales. Sei Whale is the closest in size but lacks the white right jaw and has a distinct peaked rostrum and long drooping snout. These animals had a very flat-topped rostrum.
The whales were obviously Bryde's-types. The dorsal fin was relatively small compared to body-size and although variable, always strongly hooked. The whales were however very large. Based on the length of our vessel, we estimated them to be between 10-14m long – they looked larger in size to Bryde's Whales I have seen on the Great Barrier Reef (GBR). The dorsal fin usually appeared a couple of seconds after the blow had dissipated, unlike the simultaneous appearance on animals from the GBR.
There were also no obvious pale markings along the flanks, though the water was relatively turbid and nothing below the surface could be seen. Nevertheless, Bryde's Whales usually show some bicolouration when they arch up to dive. The flanks are usually slightly paler, merging in coarse mottling into the dark back. These animals were completely different, being instead, quite dark all over (reminiscent of Sei Whale) with swirling patterns more reminiscent of one of the large baleen whales.
Compared to Bryde's Whales on the Great Barrier Reef, these whales were much more strongly patterned, longer in body and with patterning more typical of a large baleen whale.