Vancouver, Canada - Vancouver Aquarium researchers reveal genetic results from a killer whale calf carcass found near Sooke on May 4. The calf was a member of the so-called transient killer whale population. Conservation biologists consider this a positive finding and are relieved the calf is not from the endangered BC southern resident killer whale population.
On May 4, Fisheries and Oceans Canada (DFO)’s Marine Mammal Response Network responded to a public call regarding a deceased orca calf washed ashore near Sooke on Vancouver Island. DFO attended the scene to organize the immediate transfer of the carcass to the BC Animal Health Centre in Abbotsford for necropsy.
The calf appears to have died within a day or two of birth. A detailed necropsy showed its’ lungs were partially inflated and its umbilical cord was still attached. The calf measured 2.4 metres in length and weighed 220 kilograms. A small sample of skin tissue was provided for genetic analysis to Dr. Lance Barrett-Lennard, senior marine mammal scientist at the Vancouver Aquarium.
Barrett-Lennard and his Aquarium research team extracted pure DNA from the skin tissue and compared a portion of the genetic sequence with hundreds of previously-collected samples of transient and resident killer whale DNA. The genetic analysis determined the orca calf to be a transient killer whale.
Dr. Lance Barrett-Lennard says, “While it is always troubling to hear about young killer whales dying, there is some relief that the calf was not a member of the critically-endangered southern resident population, where every death moves the group closer to a breaking point”.
There are two types of killer whales found in nearshore waters of BC: mammal-eating transient killer whales and fish-eating resident killer whales. Researchers were concerned the calf was from the endangered southern resident killer whale population because its body was found in a location frequented by residents.
Like most whales, killer whale carcasses usually sink to the ocean floor making it rare to find a beached carcass. In 1999, another transient orca calf body was found in the same general area.
Transient killer whales reside atop the ocean food chain thereby accumulating large amounts of persistent organic pollutants (POP’s) in their bodies. When giving birth, a female orca will pass on most of its own organic pollutants onto the calf, decreasing its chance of survival. Orca calves have an average survival rate of 60% in the first six months of life.
DFO began the first systematic research on killer whales in the world in the early 1970’s, and has collaborated closely with the Vancouver Aquarium on this work since the early 1980’s. In that time, nearly 500 skin samples have been collected from killer whales from throughout the north Pacific. DNA extracted from these samples showed that resident and transient orcas have not mated for hundreds of generations and are genetically different, despite sharing the same habitat. The DNA has also been used to determine mating patterns and assess inbreeding.
Vancouver Aquarium researchers operate a number of programs related to marine mammal and cetacean research, including the B.C. Cetacean Sightings Network which collects and compiles sightings reports submitted by the public. These sightings data create a clearer picture of cetacean habitat use and aid understanding of these creatures and their requirements. There is further information at www.wildwhales.org.
The Aquarium also operates the B.C. Wild Killer Whale Adoption Program. By joining, members support research on wild killer whales which leads to a better understanding of the whales, their place in the ocean ecosystem, and conservation measures necessary to protect them. To learn more about adopting a killer whale, visit www.killerwhale.org
zaterdag 29 mei 2010
woensdag 26 mei 2010
Transients visit Bremerton Silverdale
A group of at least five killer whales showed up in Bremerton Wednesday morning, exciting shoreline residents who watched the orcas as they wandered through Sinclair and Dyes inlets throughout the day.
These are transient orcas, the seal-eating variety. They travel quickly and quietly, searching the nooks and crannies of our inland waterways for marine mammals — even checking out Ostrich Bay near Bremerton’s Jackson Park.
Reports of the orcas began coming in around 10:30 a.m. Wednesday, when a group of three whales were sighted off Enetai near Manette. The animals swam into Sinclair Inlet and past Puget Sound Naval Shipyard, where they were spotted by a Sunn Fjord resident about 11:45. The orcas were soon headed out of the inlet, turning in front of the Bremerton Ferry Terminal.
“They were swimming past the Turner Joy,” said Leanna Christian, an employee of The Boat Shed restaurant on the northeast side of Port Washington Narrows. She saw them pass under the Manette Bridge shortly after 12:30 p.m., heading toward Dyes Inlet.
A short time later, the whales were reported by residents of Erlands Point, Tracyton and Chico. They swam up the middle of Dyes Inlet, perhaps as far as Anna Smith Children’s Park before turning back south, pausing near the end of Erlands Point, then ducking into Ostrich Bay about 3:30 p.m. They were still in the bay at 7:30 p.m., according to a shoreline resident.
Transient orcas, which are frequently seen in Southeast Alaska and along the shores of British Columbia, are quite distinct from the more familiar Southern Resident killer whales that eat fish — mostly chinook salmon— and frequent the San Juan Islands in the summer and Central Puget Sound in the fall.
In terms of their appearance, transients have a sharper, more sharklike, dorsal fin than resident orcas with their rounded fins. Also the gray “saddle patch” around the dorsal fin stretches farther forward on transients.
Sightings of transients in Puget Sound are unusually high this year, said Howard Garrett of Orca Network, which keeps track of whale sightings.
“They are all over,” Garrett said. “They are really patrolling these waters.”
The whales that came into Sinclair and Dyes inlets Wednesday may be the same ones spotted Tuesday morning off Point No Point in North Kitsap and near Vashon Island later in the day, Garrett said.
Ken Balcomb of the Center for Whale Research was able to identify several of those whales, including a 31-year-old male known as T-74, who is distinguished by a notch in his dorsal fin. Like many transients, T-74 has been observed mainly in Southeast Alaska.
Balcomb, who has maintained a census of Southern Residents for 35 years, confirmed that this seems to be an unusual year for visits by transients.
“It sure seems to me that we have had a real episode of transient activity in the last five months,” he said.
Balcomb speculated that the transients may be around more because the residents are somewhere else. The two types of whales seem to avoid each other. Since residents normally travel in greater numbers, they may hold the dominant position.
The fish-eating residents are not around, probably because they can’t find fish to eat, Balcomb said. On the other hand, “fisherman would probably agree that there are too many seals.”
The last time transient orcas were reported in Dyes Inlet was 2004, when 13 of the animals stayed for two days. T-74 was not among them. Shoreline residents at the time reported an unusual number of seals and sea lions climbing out of the water, either onto docks or high up on the beaches.
These are transient orcas, the seal-eating variety. They travel quickly and quietly, searching the nooks and crannies of our inland waterways for marine mammals — even checking out Ostrich Bay near Bremerton’s Jackson Park.
Reports of the orcas began coming in around 10:30 a.m. Wednesday, when a group of three whales were sighted off Enetai near Manette. The animals swam into Sinclair Inlet and past Puget Sound Naval Shipyard, where they were spotted by a Sunn Fjord resident about 11:45. The orcas were soon headed out of the inlet, turning in front of the Bremerton Ferry Terminal.
“They were swimming past the Turner Joy,” said Leanna Christian, an employee of The Boat Shed restaurant on the northeast side of Port Washington Narrows. She saw them pass under the Manette Bridge shortly after 12:30 p.m., heading toward Dyes Inlet.
A short time later, the whales were reported by residents of Erlands Point, Tracyton and Chico. They swam up the middle of Dyes Inlet, perhaps as far as Anna Smith Children’s Park before turning back south, pausing near the end of Erlands Point, then ducking into Ostrich Bay about 3:30 p.m. They were still in the bay at 7:30 p.m., according to a shoreline resident.
Transient orcas, which are frequently seen in Southeast Alaska and along the shores of British Columbia, are quite distinct from the more familiar Southern Resident killer whales that eat fish — mostly chinook salmon— and frequent the San Juan Islands in the summer and Central Puget Sound in the fall.
In terms of their appearance, transients have a sharper, more sharklike, dorsal fin than resident orcas with their rounded fins. Also the gray “saddle patch” around the dorsal fin stretches farther forward on transients.
Sightings of transients in Puget Sound are unusually high this year, said Howard Garrett of Orca Network, which keeps track of whale sightings.
“They are all over,” Garrett said. “They are really patrolling these waters.”
The whales that came into Sinclair and Dyes inlets Wednesday may be the same ones spotted Tuesday morning off Point No Point in North Kitsap and near Vashon Island later in the day, Garrett said.
Ken Balcomb of the Center for Whale Research was able to identify several of those whales, including a 31-year-old male known as T-74, who is distinguished by a notch in his dorsal fin. Like many transients, T-74 has been observed mainly in Southeast Alaska.
Balcomb, who has maintained a census of Southern Residents for 35 years, confirmed that this seems to be an unusual year for visits by transients.
“It sure seems to me that we have had a real episode of transient activity in the last five months,” he said.
Balcomb speculated that the transients may be around more because the residents are somewhere else. The two types of whales seem to avoid each other. Since residents normally travel in greater numbers, they may hold the dominant position.
The fish-eating residents are not around, probably because they can’t find fish to eat, Balcomb said. On the other hand, “fisherman would probably agree that there are too many seals.”
The last time transient orcas were reported in Dyes Inlet was 2004, when 13 of the animals stayed for two days. T-74 was not among them. Shoreline residents at the time reported an unusual number of seals and sea lions climbing out of the water, either onto docks or high up on the beaches.
woensdag 5 mei 2010
One ocean, four (or more) killer whale species
Determining whether animals belong to the same species is not as black and white as you may think.
Take killer whales, for example. Scientists have been debating for years whether the ocean-dwelling mammals belong to a single species or several different ones. Now, new DNA evidence seems to indicate that killer whales should be classified in at least four different species.
Scientists used to think that Shamu and Willy of the movie “Free Willy” and other killer whales (also called orcas) were all members of a single species, Orcinus orca, which had colonized oceans all around the world. But as researchers began observing killer whales more closely, they discovered that the marine mammals seem to belong to several different groups, called ecotypes, with different feeding habits and appearances. In Antarctic waters, for example, three different ecotypes have been identified that have distinguishing eye patches; dietary preferences for either fish, seals or cetaceans and social networks that don’t intersect.
Killer whales from different ecotypes don’t seem to breed with each other — one criterion for being classified as separate species. So some scientists proposed that killer whales should be divided into different species.
But early genetic analyses didn’t support the move. Biologists often look at a loop of DNA housed in organelles called mitochondria, which produce energy for cells. Partly because it resides outside the main storehouse of genetic material in the cell’s nucleus, mitochondrial DNA can be used as a type of molecular clock to measure the time elapsed since two genetic lineages shared a common ancestor. After looking at changes in portions of the mitochondrial DNA from different killer whale ecotypes, earlier studies concluded the groups were similar enough to fall into a single species.
But recently, researchers have come to realize that some species may accumulate mitochondrial DNA changes faster or slower than others. Adélie penguins are evolving faster than previously thought (SN Online; 11/17/2009). But killer whales and other cetaceans have molecular clocks that tick slower than in other species, says Phillip Morin, a marine mammal geneticist at the Southwest Fisheries Science Center in La Jolla, Calif. As a result, examining just part of the mitochondrial DNA doesn’t give a full picture of genetic diversity of killer whales.
So Morin and his colleagues analyzed the full mitochondrial genomes of 139 killer whales from around the globe and found that the animals fall into several genetically distinct groups.
“The genetic data show that they are each independently evolving lineages,” Morin says.
The group proposes in a study published online April 22 in Genome Research that there is enough evidence to classify three ecotypes of killer whales as separate species:
Type B killer whales in the Antarctic feed only on marine mammals, especially seals that they knock off of pack ice. These killer whales have large eye patches and a two-tone grey color scheme. They are medium-size as killer whales go, falling in between the open-ocean dwelling Type A killer whales and the smaller Type C orcas.
Type C killer whales — also known as Ross Sea killer whales — eat fish and hunt under Antarctica’s pack ice. These are the smallest of the killer whales and have a small, slanted eye patch.
Transient killer whales that live in the northeastern Pacific near Alaska are the most genetically distinct of the killer whales. These killer whales eat other marine mammals, including seals, sea lions, whales and dolphins. Morin’s group estimates that this group diverged from other killer whales as a separate species about 700,000 years ago. Other groups split off more recently.
Mitochondrial DNA analysis also suggests that Type A killer whales, which feed on other cetaceans, might be further divided into other species once scientists have compiled more data about the animals’ behavior.
A new genetic study suggests three different populations of killer whales belong in their own individual species: a type that lives in the northeastern Pacific and feeds on marine mammals (top), a pack ice killer whale, which hunts seals in Antarctic waters (center) and a Ross sea killer whale, which pursues fish under the Antarctic pack ice.
“I suspect there’s going to be another four or five species,” says Robin Baird, a cetacean biologist at the Cascadia Research Collective in Olympia, Wash. What is unusual about the killer whales is that they seem to be evolving into new species based upon their eating habits, he says. Other instances of this sort of cultural divide between species are known for birds, but is extremely rare for mammals, he says.
Usually new species emerge after geographical isolation separates two groups into distinct breeding populations. But killer whales don’t have any apparent physical barriers that would keep them from breeding with each other. And scientists have learned that geographic isolation wasn’t enough to divide tree lizards, called anoles, on the Lesser Antilles island of Martinque into new species. Roger Thorpe and his colleagues Yann Surget-Groba and Helena Johansson reported their discovery April 29 in PLoS Genetics.
Not everyone is convinced that the new genetic data show that killer whales are several different species. Mitochondrial DNA is passed from mothers to their offspring and only reflects part of a species genetic heritage, points out A. Rus Hoelzel of Durham University in England. Analyzing the full genetic makeup of killer whales might show more flow of genetic information between killer whale groups than is apparent from the mitochondrial DNA. Exchange of genetic information between the groups would indicate that they aren’t separate species.
Morin also wants to examine the full genetic picture of killer whales, but he thinks the additional data will validate the finding from mitochondrial DNA that orcas belong to different species.
“My gut feeling is that these really are separate species, but the careful scientist in me wants to get a little bit more data from the nuclear DNA to really nail it down,” he says.
Take killer whales, for example. Scientists have been debating for years whether the ocean-dwelling mammals belong to a single species or several different ones. Now, new DNA evidence seems to indicate that killer whales should be classified in at least four different species.
Scientists used to think that Shamu and Willy of the movie “Free Willy” and other killer whales (also called orcas) were all members of a single species, Orcinus orca, which had colonized oceans all around the world. But as researchers began observing killer whales more closely, they discovered that the marine mammals seem to belong to several different groups, called ecotypes, with different feeding habits and appearances. In Antarctic waters, for example, three different ecotypes have been identified that have distinguishing eye patches; dietary preferences for either fish, seals or cetaceans and social networks that don’t intersect.
Killer whales from different ecotypes don’t seem to breed with each other — one criterion for being classified as separate species. So some scientists proposed that killer whales should be divided into different species.
But early genetic analyses didn’t support the move. Biologists often look at a loop of DNA housed in organelles called mitochondria, which produce energy for cells. Partly because it resides outside the main storehouse of genetic material in the cell’s nucleus, mitochondrial DNA can be used as a type of molecular clock to measure the time elapsed since two genetic lineages shared a common ancestor. After looking at changes in portions of the mitochondrial DNA from different killer whale ecotypes, earlier studies concluded the groups were similar enough to fall into a single species.
But recently, researchers have come to realize that some species may accumulate mitochondrial DNA changes faster or slower than others. Adélie penguins are evolving faster than previously thought (SN Online; 11/17/2009). But killer whales and other cetaceans have molecular clocks that tick slower than in other species, says Phillip Morin, a marine mammal geneticist at the Southwest Fisheries Science Center in La Jolla, Calif. As a result, examining just part of the mitochondrial DNA doesn’t give a full picture of genetic diversity of killer whales.
So Morin and his colleagues analyzed the full mitochondrial genomes of 139 killer whales from around the globe and found that the animals fall into several genetically distinct groups.
“The genetic data show that they are each independently evolving lineages,” Morin says.
The group proposes in a study published online April 22 in Genome Research that there is enough evidence to classify three ecotypes of killer whales as separate species:
Type B killer whales in the Antarctic feed only on marine mammals, especially seals that they knock off of pack ice. These killer whales have large eye patches and a two-tone grey color scheme. They are medium-size as killer whales go, falling in between the open-ocean dwelling Type A killer whales and the smaller Type C orcas.
Type C killer whales — also known as Ross Sea killer whales — eat fish and hunt under Antarctica’s pack ice. These are the smallest of the killer whales and have a small, slanted eye patch.
Transient killer whales that live in the northeastern Pacific near Alaska are the most genetically distinct of the killer whales. These killer whales eat other marine mammals, including seals, sea lions, whales and dolphins. Morin’s group estimates that this group diverged from other killer whales as a separate species about 700,000 years ago. Other groups split off more recently.
A new genetic study suggests three different populations of killer whales belong in their own individual species: a type that lives in the northeastern Pacific and feeds on marine mammals (top), a pack ice killer whale, which hunts seals in Antarctic waters (center) and a Ross sea killer whale, which pursues fish under the Antarctic pack ice.
“I suspect there’s going to be another four or five species,” says Robin Baird, a cetacean biologist at the Cascadia Research Collective in Olympia, Wash. What is unusual about the killer whales is that they seem to be evolving into new species based upon their eating habits, he says. Other instances of this sort of cultural divide between species are known for birds, but is extremely rare for mammals, he says.
Usually new species emerge after geographical isolation separates two groups into distinct breeding populations. But killer whales don’t have any apparent physical barriers that would keep them from breeding with each other. And scientists have learned that geographic isolation wasn’t enough to divide tree lizards, called anoles, on the Lesser Antilles island of Martinque into new species. Roger Thorpe and his colleagues Yann Surget-Groba and Helena Johansson reported their discovery April 29 in PLoS Genetics.
Not everyone is convinced that the new genetic data show that killer whales are several different species. Mitochondrial DNA is passed from mothers to their offspring and only reflects part of a species genetic heritage, points out A. Rus Hoelzel of Durham University in England. Analyzing the full genetic makeup of killer whales might show more flow of genetic information between killer whale groups than is apparent from the mitochondrial DNA. Exchange of genetic information between the groups would indicate that they aren’t separate species.
Morin also wants to examine the full genetic picture of killer whales, but he thinks the additional data will validate the finding from mitochondrial DNA that orcas belong to different species.
“My gut feeling is that these really are separate species, but the careful scientist in me wants to get a little bit more data from the nuclear DNA to really nail it down,” he says.
dinsdag 4 mei 2010
Dead orca calf Point No Point Sooke, B.C., Canada
May 4
We received a call around noon from Sharon Soderberg of the Point No Point resort near Sooke, B.C., reporting a dead orca calf washed up on their beach. She sent this photo to us, which shows a newborn calf, fetal folds still visible. Sharon said it was approximately 8.5' long, and the umbilical cord was still attached.
The Dept. of Fisheries Marine Mammal Stranding Network responded, and a necropsy was performed under the direction of Canada's DFO.
Photo by
Sharon Soderberg
We have had a number of Transient orcas in the area, but J pod had also been in the region just days before the stranding, so it isn't yet known who the calf belonged to. We will forward on any further information on this as it becomes available.
We received a call around noon from Sharon Soderberg of the Point No Point resort near Sooke, B.C., reporting a dead orca calf washed up on their beach. She sent this photo to us, which shows a newborn calf, fetal folds still visible. Sharon said it was approximately 8.5' long, and the umbilical cord was still attached.
The Dept. of Fisheries Marine Mammal Stranding Network responded, and a necropsy was performed under the direction of Canada's DFO.
Sharon Soderberg
We have had a number of Transient orcas in the area, but J pod had also been in the region just days before the stranding, so it isn't yet known who the calf belonged to. We will forward on any further information on this as it becomes available.
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