SUBHEAD: Normally chatty northern westcoast killer whales have quieted down and face increasing mortality.
By CP Staff on 27 October 2013 in the Vancuover Sun-
(http://www.vancouversun.com/technology/Normally+chatty+northern+whales+have+quieted+down+Vancouver/9079690/story.html)
Image above: Vancouver Aquarium researchers are scratching their heads over what they're calling puzzling changes seen in the killer whale pods that live off British Columbia's coast and off Alaska. From (http://www.hdwpapers.com/orca_hd_wallpaper-wallpapers.html).
There have been some puzzling changes in the behaviour of northern resident killer whales that live off the north-central coast of British Columbia and Alaska, says a marine mammal scientist from the Vancouver Aquarium.
Dr. Lance Barrett-Lennard, head of the aquarium's cetacean research team, said his team has noticed for the past two summers that the normally chatty mammals have been uncharacteristically quiet.
"They weren't vocalizing, and that was quite a striking change after years and years of being very familiar with how noisy they are and how easy to find acoustically," Barrett-Lennard said Thursday.
The cetacean team goes out in the summer to study the whales, finding the pods with the help of a hydrophone dropped over the side of the boat into the water.
The device, described by Barrett-Lennard as "basically a microphone in a salad bowl," can hear the whales within about a 25-kilometre radius and point the team in the right direction.
But finding the pods has become more difficult because they're not as loud.
"We were still blundering into them from time to time, finding them without the hydrophone and when we did, they were generally — not always, but most of the time — very quiet," Barrett-Lennard said.
Whales use sound to find each other, to locate prey and just to communicate, he said. The whales appear to be foraging actively and behaving normally in most every other way.
"We're seeing everything that we would expect to see visually but when we drop the hydrophone over the side, they're being very, very quiet," he said.
The whales have also been seen the past two summers travelling in smaller groups further offshore to find food — behaviour more typical in winter than summer.
The team has also noticed an unusually high mortality rate among pod matriarchs, with seven or eight deaths among older females in the pod in the past two years. Normally, the team notices one or two deaths per year.
The deaths are likely coincidental and not linked, he said, but the effect of their departures could affect the pod.
"We know that the matriarchs are really important in these groups.... they're the glue that hold these groups together because all of the matriarch's sons and daughters stay with her for life."
The pod population is not declining despite the deaths, because there has been no unusual calf or cow mortality.
At the same time, Barrett-Lennard said the number of the rarer Bigg's killer whales has been increasing over the past 25 years, and the two species that used to avoid one another are now spotted in almost equal measure.
Barrett-Lennard said the changes are not alarming, but do need further study.
High orca death rate puzzling
SUBHEAD: "Slowly but surely, they would go extinct," Stedman said. "That's the worry."
By Staff on 24 October 2013 for KOMO News -
(http://www.komonews.com/news/local/Researcher-High-death-rate-puzzling-behavior-in-BC-orcas--229135551.html)
A Vancouver Aquarium researcher is sounding the alarm over "puzzling" changes he's observed in the killer whale pods that live off the southern British Columbia coast.
Dr. Lance Barrett-Lennard says he fears changes in the ocean environment are prompting odd behaviour and an unusually high mortality rate.
Barrett-Lennard says the southern resident orca pod, which is found in the Salish Sea between Vancouver Island and the B.C. mainland, has lost seven matriarchs over the past two years, and he's noticed a lack of vocalizations from the normally chatty mammals.
The Vancouver Aquarium's cetacean research team says the whales were also seen the past two summers travelling in small groups, further offshore to find food - behaviour more typical in winter than summer.
At the same time, the researcher says the number of normally transient killer whales has been increasing over the past 25 years.
Barrett-Lennard says the changes are striking and need further study.
The alarming observations come on the heels of a study revealing that the number of killer whales in Puget Sound is dwindling - especially among reproductive age males.
Bruce Stedman, who heads up the Orca Relief Citizens' Alliance, says numbers from the Center for Whale Research and NOAA show the number of reproductive-age males is down 26 percent since 2009, and there are only 14 reproductive age male orcas left.
And he worries if those numbers don't get better soon, the result could be devastating.
"Slowly but surely, they would go extinct," Stedman said. "That's the worry."
.
By CP Staff on 27 October 2013 in the Vancuover Sun-
(http://www.vancouversun.com/technology/Normally+chatty+northern+whales+have+quieted+down+Vancouver/9079690/story.html)
Image above: Vancouver Aquarium researchers are scratching their heads over what they're calling puzzling changes seen in the killer whale pods that live off British Columbia's coast and off Alaska. From (http://www.hdwpapers.com/orca_hd_wallpaper-wallpapers.html).
There have been some puzzling changes in the behaviour of northern resident killer whales that live off the north-central coast of British Columbia and Alaska, says a marine mammal scientist from the Vancouver Aquarium.
Dr. Lance Barrett-Lennard, head of the aquarium's cetacean research team, said his team has noticed for the past two summers that the normally chatty mammals have been uncharacteristically quiet.
"They weren't vocalizing, and that was quite a striking change after years and years of being very familiar with how noisy they are and how easy to find acoustically," Barrett-Lennard said Thursday.
The cetacean team goes out in the summer to study the whales, finding the pods with the help of a hydrophone dropped over the side of the boat into the water.
The device, described by Barrett-Lennard as "basically a microphone in a salad bowl," can hear the whales within about a 25-kilometre radius and point the team in the right direction.
But finding the pods has become more difficult because they're not as loud.
"We were still blundering into them from time to time, finding them without the hydrophone and when we did, they were generally — not always, but most of the time — very quiet," Barrett-Lennard said.
Whales use sound to find each other, to locate prey and just to communicate, he said. The whales appear to be foraging actively and behaving normally in most every other way.
"We're seeing everything that we would expect to see visually but when we drop the hydrophone over the side, they're being very, very quiet," he said.
The whales have also been seen the past two summers travelling in smaller groups further offshore to find food — behaviour more typical in winter than summer.
The team has also noticed an unusually high mortality rate among pod matriarchs, with seven or eight deaths among older females in the pod in the past two years. Normally, the team notices one or two deaths per year.
The deaths are likely coincidental and not linked, he said, but the effect of their departures could affect the pod.
"We know that the matriarchs are really important in these groups.... they're the glue that hold these groups together because all of the matriarch's sons and daughters stay with her for life."
The pod population is not declining despite the deaths, because there has been no unusual calf or cow mortality.
At the same time, Barrett-Lennard said the number of the rarer Bigg's killer whales has been increasing over the past 25 years, and the two species that used to avoid one another are now spotted in almost equal measure.
Barrett-Lennard said the changes are not alarming, but do need further study.
High orca death rate puzzling
SUBHEAD: "Slowly but surely, they would go extinct," Stedman said. "That's the worry."
By Staff on 24 October 2013 for KOMO News -
(http://www.komonews.com/news/local/Researcher-High-death-rate-puzzling-behavior-in-BC-orcas--229135551.html)
A Vancouver Aquarium researcher is sounding the alarm over "puzzling" changes he's observed in the killer whale pods that live off the southern British Columbia coast.
Dr. Lance Barrett-Lennard says he fears changes in the ocean environment are prompting odd behaviour and an unusually high mortality rate.
Barrett-Lennard says the southern resident orca pod, which is found in the Salish Sea between Vancouver Island and the B.C. mainland, has lost seven matriarchs over the past two years, and he's noticed a lack of vocalizations from the normally chatty mammals.
The Vancouver Aquarium's cetacean research team says the whales were also seen the past two summers travelling in small groups, further offshore to find food - behaviour more typical in winter than summer.
At the same time, the researcher says the number of normally transient killer whales has been increasing over the past 25 years.
Barrett-Lennard says the changes are striking and need further study.
The alarming observations come on the heels of a study revealing that the number of killer whales in Puget Sound is dwindling - especially among reproductive age males.
Bruce Stedman, who heads up the Orca Relief Citizens' Alliance, says numbers from the Center for Whale Research and NOAA show the number of reproductive-age males is down 26 percent since 2009, and there are only 14 reproductive age male orcas left.
And he worries if those numbers don't get better soon, the result could be devastating.
"Slowly but surely, they would go extinct," Stedman said. "That's the worry."
.
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