A rare type of orca is prowling the open ocean off Alaska's shores.
Researchers with the National Oceanic and Atmospheric Administration's Alaska Fisheries Science Center have spent the last 20 years learning more about an elusive type of killer whale and recently published their results.
Offshore killer whales range from California to Alaska and can travel great distances quickly.
Researchers found they are genetically different from other types of killer whales, and they have a different size, shape and behavior pattern than other killer whales, as well.
NOAA's scientists recently published a paper summarizing their 20 years of studying the offshore killer whale population.
maandag 29 september 2008
zondag 28 september 2008
Navy’s sonar has a killer sound
The similarity between the sounds made by the killer whale and navy sonar may provoke panic in the mammal’s prey, causing mass strandings.
SCIENTISTS may have found the explanation for the role of naval sonar in the mass stranding of whales and dolphins with the discovery that ships’ equipment uses the same frequencies as killer whales.
They suggest that the bursts of sound emitted by warships to spot submarines resemble the noises used by killer whales to communicate as they track their prey. The similarity may deceive some species into thinking they are about to be attacked, so they swim for their lives.
The research, by a team including scientists from the sea mammal research unit at St Andrews University and the Woods Hole Oceanographic Institution in the United States, follows a spate of mass strandings around Europe and America.
In June this year 26 common dolphins beached themselves along the south coast of Corn-wall. Last week the Ministry of Defence admitted that 30 sonar-equipped naval vessels had been staging an exercise just beforehand.
Peter Tyack, a senior scientist at Woods Hole, said: “Some naval sonar uses pulses of similar frequency and duration to the pulses emitted by killer whales and is very loud. It seems to have a particularly strong effect on species, such as small beaked whales, of which killer whales are the primary predator.”
Suspicion fell on naval sonar after unusual mass strandings of beaked whales were first reported in the early 1960s, when such devices became commonly deployed. However, many nonnaval ships also use sonar without being linked to strandings. Additionally, some species beach themselves when there is no naval activity.
Tyack believes that deep divers such as Cuvier’s and Blainville’s whales are among those most likely to confuse sonar with predators. Dolphins may also be vulnerable.
On a research cruise last year he and his colleagues found a Blainville’s whale foraging over a part of the sea bed that had been equipped with hydro-phones - underwater microphones to detect movements and noises. They tagged the whale so that they could track the direction and course of its dives as well as the sonar pulses it emitted as it searched for food a mile beneath the surface.
The researchers played a recording of the sounds made by a pod of killer whales through underwater loud-speakers, and the Blainville’s whale suddenly switched to “stealth mode”. It stopped emitting the characteristic echo-location pulses normally used to find prey and then glided slowly and silently back to the surface for air before leaving the immediate area.
When the experiment was repeated, this time with naval sonar directed at the animal, it caused a similar disruption to its behaviour patterns.
Such research must be repeated with more animals to be conclusive, but Tyack believes other factors support the link with killer whales.
Naval sonar ranges include low frequencies of 3-10kHz, a range also used by killer whales. The MoD has confirmed that the sonar used in its June exercises had frequencies in the 2-50kHz range.
Civilian ships and fishing vessels, by contrast, tend to use sonar with shorter pulses and higher frequencies. This may explain why they appear not to cause beachings.
One positive outcome of the research could be that navies are able to recalibrate their sonars to avoid harming whales and dolphins.
In Britain the number of strandings of cetaceans has doubled to more than 700 in 10 years. Professor Ian Boyd, director of the sea mammal research unit at St Andrews, is leading the investigation into the cause of strandings aboard the research vessel Roger Revelle off the Bahamas. He is trying to repeat the whale-tracking experiments of last year.
In an e-mail from the ship he said: “One theory is that these whales confuse the sonars for killer-whale calls and have a magnified antipredator response that ends up with them becoming stranded.”
Tyack points out that a far larger threat is that of being hit by ships or caught in fishing nets: 1,000 sea mammals a day are thought to die that way.
SCIENTISTS may have found the explanation for the role of naval sonar in the mass stranding of whales and dolphins with the discovery that ships’ equipment uses the same frequencies as killer whales.
They suggest that the bursts of sound emitted by warships to spot submarines resemble the noises used by killer whales to communicate as they track their prey. The similarity may deceive some species into thinking they are about to be attacked, so they swim for their lives.
The research, by a team including scientists from the sea mammal research unit at St Andrews University and the Woods Hole Oceanographic Institution in the United States, follows a spate of mass strandings around Europe and America.
In June this year 26 common dolphins beached themselves along the south coast of Corn-wall. Last week the Ministry of Defence admitted that 30 sonar-equipped naval vessels had been staging an exercise just beforehand.
Peter Tyack, a senior scientist at Woods Hole, said: “Some naval sonar uses pulses of similar frequency and duration to the pulses emitted by killer whales and is very loud. It seems to have a particularly strong effect on species, such as small beaked whales, of which killer whales are the primary predator.”
Suspicion fell on naval sonar after unusual mass strandings of beaked whales were first reported in the early 1960s, when such devices became commonly deployed. However, many nonnaval ships also use sonar without being linked to strandings. Additionally, some species beach themselves when there is no naval activity.
Tyack believes that deep divers such as Cuvier’s and Blainville’s whales are among those most likely to confuse sonar with predators. Dolphins may also be vulnerable.
On a research cruise last year he and his colleagues found a Blainville’s whale foraging over a part of the sea bed that had been equipped with hydro-phones - underwater microphones to detect movements and noises. They tagged the whale so that they could track the direction and course of its dives as well as the sonar pulses it emitted as it searched for food a mile beneath the surface.
The researchers played a recording of the sounds made by a pod of killer whales through underwater loud-speakers, and the Blainville’s whale suddenly switched to “stealth mode”. It stopped emitting the characteristic echo-location pulses normally used to find prey and then glided slowly and silently back to the surface for air before leaving the immediate area.
When the experiment was repeated, this time with naval sonar directed at the animal, it caused a similar disruption to its behaviour patterns.
Such research must be repeated with more animals to be conclusive, but Tyack believes other factors support the link with killer whales.
Naval sonar ranges include low frequencies of 3-10kHz, a range also used by killer whales. The MoD has confirmed that the sonar used in its June exercises had frequencies in the 2-50kHz range.
Civilian ships and fishing vessels, by contrast, tend to use sonar with shorter pulses and higher frequencies. This may explain why they appear not to cause beachings.
One positive outcome of the research could be that navies are able to recalibrate their sonars to avoid harming whales and dolphins.
In Britain the number of strandings of cetaceans has doubled to more than 700 in 10 years. Professor Ian Boyd, director of the sea mammal research unit at St Andrews, is leading the investigation into the cause of strandings aboard the research vessel Roger Revelle off the Bahamas. He is trying to repeat the whale-tracking experiments of last year.
In an e-mail from the ship he said: “One theory is that these whales confuse the sonars for killer-whale calls and have a magnified antipredator response that ends up with them becoming stranded.”
Tyack points out that a far larger threat is that of being hit by ships or caught in fishing nets: 1,000 sea mammals a day are thought to die that way.
vrijdag 26 september 2008
Stranded orca back at sea
A seven-metre long orca which was stranded after washing up on Papamoa Beach near Tauranga on Saturday morning has been successfully sent back to sea.
"Nobbie" is well known to local conservationists and has been on the beach before.
Several hundred people turned out to the beach where the orca whale had stranded and volunteers helped keep the animal wet and comfortable.
Department of Conservation spokeswoman Katrina Knill says a good tide and a freshly dug trench helped to get Nobbie back into the water sooner than anticipated.
She says he looks like he will be all right but she is urging the public to contact the Conservation Department if they see him getting too close to shore.
Orca beaches at Papamoa Beach (NZ)
Volunteers working to keep orca whale wet after it beached at Papamoa Beach on Bay of Plenty coast.
Several hundred people have turned out to Papamoa Beach on the Bay of Plenty coast where a killer whale has stranded.
The orca is well-known to local conservationists, who have nicknamed him Nobby.
It is not the first time the marine mammal has thrown itself onto the beach. Katrina Knill from the Department of Conservation says despite washing up at 6am, Nobby is in good shape and it is hoped there will be a good outcome. Volunteers are helping to keep the whale wet and comfortable.
A second attempt to herd Nobby back to sea will be made on high tide around 5:30 this evening.
Several hundred people have turned out to Papamoa Beach on the Bay of Plenty coast where a killer whale has stranded.
The orca is well-known to local conservationists, who have nicknamed him Nobby.
It is not the first time the marine mammal has thrown itself onto the beach. Katrina Knill from the Department of Conservation says despite washing up at 6am, Nobby is in good shape and it is hoped there will be a good outcome. Volunteers are helping to keep the whale wet and comfortable.
A second attempt to herd Nobby back to sea will be made on high tide around 5:30 this evening.
vrijdag 19 september 2008
Declining salmon runs blamed for wilderness tourism slump
Few people in British Columbia know how to find killer whales better than Bill MacKay, who tracks them in a high-speed, super-quiet boat from Port McNeill, on northern Vancouver Island.
But Mr. MacKay, who with his wife, Donna, runs MacKay Whale Watching, has had an increasingly difficult time finding large numbers of killer whales to show his customers this year.
All along the B.C. Coast, wilderness tourism operators who run bear-viewing, whale-watching and sport-fishing resorts are reporting tough times because of declining salmon runs.
But the biggest impact may be occurring in the Broughton Archipelago, where Mr. MacKay operates, and where pink salmon runs have all but vanished, sending a shock wave through the region's ecosystem.
"Some of the northern pods are just not here," Mr. MacKay said yesterday. "And we've had three occasions [this summer] when we did not see any orcas at all. That's pretty weird."
He said northern killer whales visit the area during the summer months, collecting in big social gatherings where breeding takes place.
"When they get together like that it's called Super Pod Day, and we will see over 100 dorsal fins out there at a time," Mr. MacKay said. "That didn't happen this year, for the first time since we've been collecting data, which is almost 30 years."
Mr. MacKay said it's not coincidental that the whales have vanished along with the salmon.
"It's pretty simple. ...What do you think these orcas eat?" he said.
Surveys by the Department of Fisheries and Oceans indicate pink salmon stocks have fallen to extremely low levels in the Broughton Archipelago. In Glendale Creek, a key indicator stream, there have been only 19,000 spawners counted this year, compared with 264,000 last year.
Pink salmon, which usually spawn in prodigious numbers, are a keystone species on the West Coast. Chinook salmon, the mainstay of the orca diet, feed on young pinks, while grizzly and black bears depend on spawning adult pink salmon to bulk up for hibernation.
Howard Pattinson, owner of Tide Rip Tours, a grizzly-bear viewing business based in Telegraph Cove, said the pink collapse has forced bears to rely on late berry crops and sedge grasses for nutrition.
"We're used to seeing bears eat 15 to 20 fish an hour. Now once a day we might see a bear catch one fish," Mr. Pattinson said. "We are seeing big male bears killing [yearling] cubs and eating them. ...It's pretty shocking for the tourists when they see raw nature like that."
Mr. Pattinson said he's worried about the future of his business.
"The bears are now eating berries and sedges. It's enough to get through the winter, but not enough for pregnant females. They'll either reabsorb their embryos or abort this winter. ...Next spring, I don't think there'll be any cubs," he said.
Brian Gunn, president of the Wilderness Tourism Association, said the collapse of salmon stocks is threatening the survival of ecotourism businesses.
"The bear-viewing businesses, the whale-watching operations, they built up a lot of equity showing people these wild animals. Now the fish aren't there and they are seeing their equity drain away. ...If the salmon go, so does the wildlife, and so does the business."
Mr. Gunn blamed the fish-farming business, saying a heavy concentration of net pens in the Broughton Archipelago has created sea-lice epidemics which kill young salmon.
But Mr. MacKay, who with his wife, Donna, runs MacKay Whale Watching, has had an increasingly difficult time finding large numbers of killer whales to show his customers this year.
All along the B.C. Coast, wilderness tourism operators who run bear-viewing, whale-watching and sport-fishing resorts are reporting tough times because of declining salmon runs.
But the biggest impact may be occurring in the Broughton Archipelago, where Mr. MacKay operates, and where pink salmon runs have all but vanished, sending a shock wave through the region's ecosystem.
"Some of the northern pods are just not here," Mr. MacKay said yesterday. "And we've had three occasions [this summer] when we did not see any orcas at all. That's pretty weird."
He said northern killer whales visit the area during the summer months, collecting in big social gatherings where breeding takes place.
"When they get together like that it's called Super Pod Day, and we will see over 100 dorsal fins out there at a time," Mr. MacKay said. "That didn't happen this year, for the first time since we've been collecting data, which is almost 30 years."
Mr. MacKay said it's not coincidental that the whales have vanished along with the salmon.
"It's pretty simple. ...What do you think these orcas eat?" he said.
Surveys by the Department of Fisheries and Oceans indicate pink salmon stocks have fallen to extremely low levels in the Broughton Archipelago. In Glendale Creek, a key indicator stream, there have been only 19,000 spawners counted this year, compared with 264,000 last year.
Pink salmon, which usually spawn in prodigious numbers, are a keystone species on the West Coast. Chinook salmon, the mainstay of the orca diet, feed on young pinks, while grizzly and black bears depend on spawning adult pink salmon to bulk up for hibernation.
Howard Pattinson, owner of Tide Rip Tours, a grizzly-bear viewing business based in Telegraph Cove, said the pink collapse has forced bears to rely on late berry crops and sedge grasses for nutrition.
"We're used to seeing bears eat 15 to 20 fish an hour. Now once a day we might see a bear catch one fish," Mr. Pattinson said. "We are seeing big male bears killing [yearling] cubs and eating them. ...It's pretty shocking for the tourists when they see raw nature like that."
Mr. Pattinson said he's worried about the future of his business.
"The bears are now eating berries and sedges. It's enough to get through the winter, but not enough for pregnant females. They'll either reabsorb their embryos or abort this winter. ...Next spring, I don't think there'll be any cubs," he said.
Brian Gunn, president of the Wilderness Tourism Association, said the collapse of salmon stocks is threatening the survival of ecotourism businesses.
"The bear-viewing businesses, the whale-watching operations, they built up a lot of equity showing people these wild animals. Now the fish aren't there and they are seeing their equity drain away. ...If the salmon go, so does the wildlife, and so does the business."
Mr. Gunn blamed the fish-farming business, saying a heavy concentration of net pens in the Broughton Archipelago has created sea-lice epidemics which kill young salmon.
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