Known only from DNA samples from whaling samples and the occasional body from a stranding scientists for the first time have confirmed a sighting of a rare whale.
The Omura’s whales live off the coast of Madagascar and are often confused for the Bryde’s whales because they look so much alike. Scientists though have made the first field observations of this rare whale and published their results in Royal Society Open Science journal.
The study describes the behaviour of feeding in the shallow waters off the coast of Madagascar and also describes the vocalisations of the whales.
While the Omura’s whale is similar to the Bryde’s whale there are distinct differences allowing people to recognise the species. The Omura’s is smaller than the Brydes and most noticeable are the distinct markings around the lower jaw. The Omura’s have a white marking on the left side of the jaw and a dark marking on the right side.
The species was set apart from other whales as recently as 2003 when DNA samples from whaling victims were analysed. The data was further confirmed with samples taken from strandings on the Pacific coast but no confirmed sightings of the species in the wild had been made until this study.
“Over the years, there have been a small handful of possible sightings of Omura’s whales, but nothing that was confirmed,” says lead author Salvatore Cerchio, who led the research while at the Wildlife Conservation Society. He is now at the New England Aquarium (NEAQ) and a guest investigator at the Woods Hole Oceanographic Institution (WHOI). “They appear to occur in remote regions and are difficult to find at sea because they are small–they range in length from approximately 33 to 38 feet–and do not put up a prominent blow.”
“What little we knew about these whales previously came primarily from eight specimens of Omura’s whales taken in Japanese scientific whaling off the Solomon and Keeling Islands and a couple strandings of dead animals in Japan,” Cerchio adds. “This is the first definitive evidence and detailed descriptions of Omura’s whales in the wild and part of what makes this work particularly exciting.”
Cericho and his team of marine researchers believe that they may have seen a Omura’s whale back in 2011 but like so many mis-identified it as a Bryce’s whales. Because so little is known of the whale the are no figures yet as to just how rare this species is in the wild. One reason for the mis-identification is that it was not believed that Madagascar was in the range of the Omura’s whale.
Once the first sighting was made in 2013 the team soon saw more of the species in the waters and started to recognise the physical markings that made the Omura’s recognisable.
Between 2013 and 2015 the researchers were able to study 44 groups of whales in Madagascar’s waters. They were also able to photo-id 25 individuals. Research is set to continue this year with the researchers hoping to be able to get a more accurate estimate of the local population and do further studies in behaviour and vocalisations.
Cerchio also hopes to work with the Woods Hole Oceanographic Institute (WHOI) in deploying a series of hydrophones to be able to better understand the range of the Omura’s whale.
Leave a Reply