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The researchers obtained samples of whales that live in almost inaccessible seas. During 40 days, nine expeditionaries ventured in search of these unknown animals. It would be the largest cetacean on the planet that still remains to be described.
For the first time a team of scientists managed to obtain samples of fat and skin from a type of killer whale that could be a new species. It would be the “greatest animal on the planet that still remains to be described and a clear signal of how little we know about the life of our oceans,” says researcher Bob Pitman of the Southwest Fisheries Scientific Center, which is dependent on the National Oceanic and Atmospheric Administration (NOAA).
Not all killer whales that swim in the world’s oceans have the same physical characteristics. In fact, there are several different ecotypes of these animals, each of which has morphological, coloration, geographical distribution and diet specificities.
Despite these differences, it is considered that they all belong to the same species. However, one doubt has remained unresolved so far: the type D orca is so different from the others that scientists believe it would be a different species. On January 6 of this year, a team of nine people, led by Bob Pitman, sailed from Ushuaia, in the Argentine Patagonia, to the frigid waters of Cape Horn decided to solve the unknown.
One of the most unknown animals of the ocean
Beyond some isolated sightings in New Zealand and in the Indian Ocean, orcas live in sub-Antarctic regions of very difficult access due to their strong winds and dangerous seas . In fact, these areas have been the scene of innumerable shipwrecks. That is why the sightings of these orcas are rare and, until now, it had been impossible to obtain samples of these animals.
“In the other orca ecotypes, biopsies could have been done because they live in much more accessible places,” explains Mariano Sironi, scientific director of the Institute of Whale Conservation of Argentina and member of the expedition. “If you want to find a B2 orca you can go to the Strait of Gerlache, you spend a day or two and you will see them almost certainly. On the other hand, if you are looking for a D type you can spend two whole weeks navigating the area and not see a single one, “says Sironi.
Even so the nine expeditionaries, including six scientists from the United States, Australia, New Zealand, Argentina and England, sailed for 40 days south of Cape Horn in the vicinity of the Diego Ramírez Islands, one of the worst places climate of the world, with the aim of finding and finding orcas type D. “We did not know each other and live all that time in a sailboat 24 meters long, in a kind of ‘Big Brother’ ocean, it was an interesting personal experience “, Says Sironi.
During the first week the weather was relatively good and the expedition members were able to navigate through the area called Point D, a site in the open sea that coincides with the edge of the slope where the depths plummet towards thousands of meters of darkness where these mysterious orcas live .
“We communicate several times on the radio with the captains of the fishing boats that look for deep-sea cod, because they usually see the orcas approaching to prey on their fishing,” says Sironi. However, the fishermen had only seen animals type A lately and the first week of expedition ended without success. The following eight days the sailboat had to anchor in a bay of the Wollaston Islands to wait for the bad weather to pass for the entire second week of expedition . On the 16th, after confirming a window of relative good weather, the vessel set sail again towards point D. That morning, at 5:40 in the morning, the so-called killer whales appeared.
“At that time we were all sleeping and it was the captain who detected them. To the shouts we got up, all with a lot of excitement, and in three minutes we were dressed and prepared on the deck of the ship. We had killer whales completely next to us! There were 30 animals circling around the boat. They walked 200 meters away and then came back closer. That lasted three hours and a half, “says Sironi.
The differences of the orca type D
With a crossbow that shoots a harmless dart for the animals, the scientists managed to obtain for the first time three biopsies of skin and fat that will be analyzed in a laboratory to be able, finally, to confirm whether or not it is a new species.
“Orcas belonging to ecotype A or regular has the pattern of black and white coloration while type B2 is more yellowish,” explains the scientist. But of all the differences that can be found among different animals, ecotype D has the most distinctive physical characteristics: an eye patch much smaller than the regular, a dorsal fin more curved and pointed and a more round and robust head.
As little is known about them, it is believed that they feed on squid and fish and that they do not interbreed with the other orcas ecotypes due to the isolation of their habitat. The latter is, in fact, another reason why it is believed that it may be a different species. “If this isolation has taken place long enough, in evolutionary terms it is possible that this ecotype has evolved to the point of separating into a different species,” explains Sironi.
It was in 1955 that scientists discovered type D orcas, when 17 of these animals washed up on the shore of a beach in New Zealand. However, for many years researchers thought it was a genetic mutation since it was not known of other similar sightings.
It was not until 50 years later that Pitman discovered the presence of this type of killer whale in the Indian Ocean observing photographs compiled by the French scientist Paul Tixier. Its location a quarter of a circle around the world of New Zealand suggested that relatives of those beached killer whales were alive and perhaps widely distributed. Since then, the growing tourism in Antarctica has generated photographs of unprecedented quality and quantity. Pitman and collaborators compiled and cataloged orca images, including those obtained from touristic vessels, and among the tens of thousands of images they collected found six additional records of New Zealand killer whales.
In addition, the scientists compared the genomes of the orca type D, rescued from the skeleton of one of the animals stranded 1955, with those of the most common killer whales A, B, and C.
The results showed that genetic differences of type D date back almost 400,000 years. Even so, it was necessary to collect more evidence to confirm if it is indeed a new species. That moment has arrived and this successful expedition in Cape Horn may finally deliver the necessary information, so awaited by science, to be able to decipher the mystery of the orca type D.
Source: Semana Sostenibilidad