A threatened population of killer whales that spends much of the year hunting seals off the British Columbia coast has been identified by an international team of scientists as a distinct species separated from its fellow orcas in Canada and elsewhere about 700,000 years ago.
The whales, known as the North Pacific Transients, have long been understood to have a different prey preference than their fish-eating cousins, as well as subtle physical anomalies, such as a more pointed dorsal fin.
But a genetic study involving 16 American and Danish scientists, led by the U.S. National Marine Fisheries Service, has concluded that the estimated population of about 300 individual North Pacific Transients is globally unique — an animal with so many DNA differences from its closest relatives around the world that it should be classified as a stand-alone species.
If the proposal is backed by the broader scientific community, the tiny population of whales off the Pacific Coast would essentially become Canada's scarcest species — with fewer numbers than either the endangered North Atlantic right whale or the whooping crane, both of which have between 300 and 400 individuals.
"It's a very exciting story," said John Ford, a University of British Columbia killer whale expert and federal fisheries scientist. "We've suspected this for many years but just haven't had the strength of evidence that this study has provided."
The results of the orca DNA project, published in the latest issue of the journal Genome Research, were based on samples tested from hundreds of specimens collected around the world.
The study, led by California-based geneticist Phillip Morin of the U.S. National Oceanic and Atmospheric Administration, has also tentatively identified two killer whale populations near Antarctica as separate species.
But the most distinctive of all orca populations was the North Pacific Transients, which move annually in small hunting groups between the coasts of Northern California, Oregon and Washington, along the B.C. shore and as far north as Alaska.
"Not only are they ecologically and morphologically distinct from other high-latitude killer whales, but genetically they are the most divergent type, diverging from all other killer whale types approximately 700,000 years ago," the study states.
Morin told Canwest News Service that this "relatively ancient" separation of the North Pacific Transients from other killer whales was key to their proposed designation as a separate species.
He added that the finding reinforces the importance of conservation policies that treat the transients "separately from all other killer whales for management purposes."
Morin added that other "resident" and "offshore" orca populations that inhabit Canadian waters could eventually be declared independent as well, as more information about their habits, physiology and genetics is gathered.
Ford says the transients are already treated as a separate population in Canada in terms of conservation strategies. Overall, he says, the transients are in a relatively healthy state — currently increasing in numbers by two or three per cent per year — but are considered "threatened" under Canada's endangered species legislation because of their relatively small population and heavy accumulation of toxins such PCBs via target prey.
Ford says that along with different feeding habits and certain physical features, the transients "never mix with other populations" and are clearly "acoustically" distinct from other killer whales.
"They are very quiet," he says, "because they hunt by stealth" when targeting "smart" seals and sea lions unlike the salmon-eating killer whales of southern B.C. that simply plow into schools of prey.
Ford said the transients 700,000-year-old split from other orcas is a "really striking" discovery that is "a surprise to all of us" who study killer whales.
"It really helps us better understand the evolution of the species."
vrijdag 23 april 2010
maandag 12 april 2010
Killer whales attack Patch the gray whale in Saratoga Passage in big rumble Sunday
A roving pack of transient killer whales attacked an adult gray whale Sunday in a Puget Sound rumble witnessed by a boat full of whale watchers.
Recorded live by one of the tourists, the attack occurred in Saratoga Passage, between Camano and Whidbey islands, when a pack of seven transient orca whales rammed an adult gray whale.
Not just any gray, but Patch, as the male, believed to be about 25 years old, is known. A regular visitor, he was first sighted in 1991 and has a following of fans who track his comings and goings in Puget Sound every year.
"Patch must be our most famous whale," said Susan Berta of Orca Network, a nonprofit advocacy group. After the attack the whale swam to a shallow beach north of Langley around 2 p.m., and appeared to rest for a bit, not feeding, but just coming to the surface to breathe, Berta said. It is not known if, or how badly, he was injured, Berta said.
"This was not hunting; they rammed him several times, then he rolled on his back, as a protective measure," Berta said. The gray whale was seen Monday morning near Hat Island, and appeared to be normal, but no one knows for sure, she said.
It is unusual for transients to take on an adult gray whale. The orcas usually prey on gray whale calves as the young animals cruise the outer coast with their mothers.
Transient killer whales mostly frequent the waters of British Columbia, but also are found in Puget Sound, especially when they are chasing prey. They prefer mammals — seals, sea lions and even whales. The orca whales in Puget Sound's southern resident population, in contrast, eschew mammals and eat only fish, particularly chinook salmon.
Orca diet is cultural: The animals learn what's food for them from their families, and pass it along to the next generation.
Brad Hanson, biologist with the National Marine Fisheries Service, was out on the water watching the transients Sunday. He watched as the pack took on at least one seal. The adult orcas hung back during the hunt, to allow younger animals to practice their skills.
"Right in our front yards we literally have these major predators. It's not something you have in many other areas," Hanson said.
"They were taking a few runs at it, while the adults were circling nearby, standing off," he said.
It is not unusual for biologists to discover rake marks on gray whales, the result of tangling with killer whales. Adult grays are no easy mark. Big and powerful, they are capable of striking powerful blows with their tails to defend themselves.
Berta said there had been several instances in the last several weeks in which transients rammed gray whales.
There are about 20,000 gray whales in the population that regularly migrates up and down Washington's coast. Another small population of grays frequents the inner waters of Puget Sound and the Strait of Juan de Fuca with such regularity the locals sometimes name them.
Recorded live by one of the tourists, the attack occurred in Saratoga Passage, between Camano and Whidbey islands, when a pack of seven transient orca whales rammed an adult gray whale.
Not just any gray, but Patch, as the male, believed to be about 25 years old, is known. A regular visitor, he was first sighted in 1991 and has a following of fans who track his comings and goings in Puget Sound every year.
"Patch must be our most famous whale," said Susan Berta of Orca Network, a nonprofit advocacy group. After the attack the whale swam to a shallow beach north of Langley around 2 p.m., and appeared to rest for a bit, not feeding, but just coming to the surface to breathe, Berta said. It is not known if, or how badly, he was injured, Berta said.
"This was not hunting; they rammed him several times, then he rolled on his back, as a protective measure," Berta said. The gray whale was seen Monday morning near Hat Island, and appeared to be normal, but no one knows for sure, she said.
It is unusual for transients to take on an adult gray whale. The orcas usually prey on gray whale calves as the young animals cruise the outer coast with their mothers.
Transient killer whales mostly frequent the waters of British Columbia, but also are found in Puget Sound, especially when they are chasing prey. They prefer mammals — seals, sea lions and even whales. The orca whales in Puget Sound's southern resident population, in contrast, eschew mammals and eat only fish, particularly chinook salmon.
Orca diet is cultural: The animals learn what's food for them from their families, and pass it along to the next generation.
Brad Hanson, biologist with the National Marine Fisheries Service, was out on the water watching the transients Sunday. He watched as the pack took on at least one seal. The adult orcas hung back during the hunt, to allow younger animals to practice their skills.
"Right in our front yards we literally have these major predators. It's not something you have in many other areas," Hanson said.
"They were taking a few runs at it, while the adults were circling nearby, standing off," he said.
It is not unusual for biologists to discover rake marks on gray whales, the result of tangling with killer whales. Adult grays are no easy mark. Big and powerful, they are capable of striking powerful blows with their tails to defend themselves.
Berta said there had been several instances in the last several weeks in which transients rammed gray whales.
There are about 20,000 gray whales in the population that regularly migrates up and down Washington's coast. Another small population of grays frequents the inner waters of Puget Sound and the Strait of Juan de Fuca with such regularity the locals sometimes name them.
donderdag 8 april 2010
A51 had a new calf
Ceteceanlab reports:
We awoke to a thin layer of snow this morning, which pushes away the feeling of spring. Yet, the arrival of whales in recent days has convinced us that spring is really here. Two humpback whales spent the day in Taylor Bight while we listened to A4 and A5 resident orca calls in Whale Channel. Late yesterday afternoon the orca family referred to as the A51s decided to come down Whale Channel and passed our Lab; we went out in our boat to check on them. A61, the brother of A51 was way in front by about a mile when we approached them. A51 and A85, her 5 year old calf were travelling close together accompanied by two pacific white-sided dolphins when we noticed a tiny black and white energy bundle which to our delight is a new calf for A51. A85 took the two dolphins close to our boat so A51 and her calf had some privacy as they travelled by the Gitga'at seaweed camp of Kyel. The whales continued heading south in Caamano Sound all the while the young calf breaching and speeding between its siblings. What an amazing start to a whole new season of whale encounters. Can it get any better then this....?
We awoke to a thin layer of snow this morning, which pushes away the feeling of spring. Yet, the arrival of whales in recent days has convinced us that spring is really here. Two humpback whales spent the day in Taylor Bight while we listened to A4 and A5 resident orca calls in Whale Channel. Late yesterday afternoon the orca family referred to as the A51s decided to come down Whale Channel and passed our Lab; we went out in our boat to check on them. A61, the brother of A51 was way in front by about a mile when we approached them. A51 and A85, her 5 year old calf were travelling close together accompanied by two pacific white-sided dolphins when we noticed a tiny black and white energy bundle which to our delight is a new calf for A51. A85 took the two dolphins close to our boat so A51 and her calf had some privacy as they travelled by the Gitga'at seaweed camp of Kyel. The whales continued heading south in Caamano Sound all the while the young calf breaching and speeding between its siblings. What an amazing start to a whole new season of whale encounters. Can it get any better then this....?
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