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It is always deceptive when trying to estimate
the size of a group of dolphins. Often, as with
these Frasers dolphins,
there can be as many dolphins
below the surface as there are above at any one time.
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Photo: Chris Johnson |
May 11, 2001
Cetacean Diversity
Real Audio
28k
Log Transcript
In contrast to the poor weather conditions we experienced in the Solomon Sea earlier this week, the waters of the Bismarck Sea have been much calmer. The glassy sea surface has made the conditions ideal for spotting whales.
The majority of our survey time this leg has seen us in the company of sperm whales. Interestingly, the past two days of searching has seen the array devoid of the constant clicks to which we have become accustomed in Papua New Guinea. This is not to say that the seas have been silent. Quite the contrary, early this morning just after sunrise, the clicks, whistles and squeals of dolphins filled the Odyssey. It was not long before we spotted the source, a group of leaping and porpoising dolphins rushing toward the boat.
Suddenly they were weaving and dodging beneath the bow with the crew enthusiastically leaning over the rails. We never tire of watching the antics of the dolphins. The calm conditions allow us to view these animals through the surface, their beaks and eyes clearly visible as they turn from side to side perhaps to look at us. We can see the myriad of scrapes and scars and the sweeping blazes of color assist us in identifying and then recording the sighting of the species.
Perhaps the easiest animals to identify are the effervescent spinner dolphins, whose aerial displays always give away their identities. We have also observed Fraser's and Pan Tropical Spotted dolphins as well as a large group of subdued pilot whales, quietly logging at the surface. However, even in the most ideal conditions we are unable to record the exact number of animals present, definitively interpret their behavior, or often even identify the species. This morning was a perfect example of just how elusive these creatures can be.
Dawn afforded a rare sighting of a beaked whale. Beaked Whales are the most difficult for researchers to identify for they are very swift and are usually seen taking a only few breathes of air at the surface. This whale passed by the Odyssey for four breathes and then disappeared below the surface. The crew were thrilled by its sighting which provides scientists with another valuable piece of data which is slowly giving us an understanding about distribution of various cetaceans throughout the world's oceans.
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A group of short finned pilot whales
are seen 'logging' at the surface.
'Logging' is thought to be a form of rest.
The whales hang motionless and generally face the same
direction.
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Photo: Chris Johnson |
The lives of whales and dolphins are hidden for the most part well below the surface of the sea. They remain elusive subjects for scientific study. Until recently, most of what we knew about cetaceans came from commercial whalers as well as aquariums. Through expeditions such as the Voyage of the Odyssey we are able to collect behavioral, toxicological and bioacoustic data from these animals in a completely benign manner. Each day we spend out here among the whales, we are able to understand the depths of their world just a little more, with opportunities that offer us tantalizing glimpses into the lives of these marine mammals in their natural environment.
It is only by increasing our understanding of these animals that we can truly learn to appreciate their significance and the importance of protecting their ocean realm.
This is Genevieve Johnson speaking to you from the Bismarck Sea as we head to the port of Rabaul to pick up Roger Payne.
Log by Genevieve Johnson
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