SEATTLE -- A little over a year after researchers feared a drop in the Northwest's endangered killer whale population meant disaster, the number of orcas has bounced back with six new babies and no whales lost.
Though scientific evidence is skimpy, some whale experts say the good news might be the result of enough salmon for the majestic black-and-white mammals to eat. Others say so little is known about orcas that the baby boom could be due to any number of factors - or simply a statistical fluke.
Whatever the reason, they're overjoyed about the new arrivals.
"We're all very happy to see so many births," said Susan Berta of the Whidbey Island-based Orca Network.
"We're all hoping that they find lots of fish to keep them healthy and keep the mothers in good condition so they can feed the calves," she said.
The Center for Whale Research says that in 2008, eight orcas in the three pods, J, K and L, that make up the southern resident population in Washington and southwest British Columbia went missing and were presumed dead, including two females of reproductive age and the 98-year-old matriarch of K Pod. With just one surviving birth that year, the total in the three pods as of December 2008 dropped to 82.
That alarmed researchers - "This is a disaster," Ken Balcomb, a senior scientist at the San Juan Island-based center, said in October of that year.
But in 2009, no deaths were reported and five new calves were spotted, giving a December total of 87. A sixth infant was born Jan. 3 while its family, J Pod, was near Seattle on a winter visit, making it 88.
Both Balcomb and Howard Garrett, director of the Orca Network, think food might have something to do with it.
The whales feed on salmon - particularly chinook salmon, the largest and arguably tastiest of the Pacific species. Chinooks are listed as threatened or endangered in several Northwest waterways, including Puget Sound and the Columbia River.
"Unfortunately, they're very picky," Garrett said, with chinooks sometimes making up 80 percent of the whales' diet. It sounds simplistic, Garrett said, but "the way that we can tag the population fluctuations is directly from the chinook runs."
Taken as a whole, the runs in the region have held steady over at least the past two years, he said.
It's not that simple, said Brad Hanson, a wildlife biologist with the federal Northwest Fisheries Science Center in Seattle. He said that for much of the year, little is known about what salmon stocks the whales eat and where.
The southern orcas can range widely, from the north end of Canada's Vancouver Island to Northern California for K and L pods.
Depending on the river, he said, some salmon stocks are up, some down, some about average. And orcas face the same problem that bedevils all fishermen: hitting the right run at the right time under the right conditions.
"There's just so many different variables involved," Hanson said.
The three pods in the southern resident community - J Pod based in the San Juan Islands, K Pod in the Strait of Juan de Fuca and L Pod off the coast - are genetically and behaviorally distinct from other killer whales. Besides sticking to this region, their sounds are considered a unique dialect, they tend to mate only within their community and they usually gather each year to socialize in a "super pod" near the San Juans.
Orcas have a 17-month gestation period, so at least six of the whales were pregnant a year ago. From a distance it's hard to tell whether an orca is pregnant, so no one on land knew they were expecting when worries over the lost whales emerged.
Over the years the Center for Whale Research has tracked the southern population, their numbers have varied from a low of 71 in 1977 to a high of 97 in 1996, and the current total of 88 only matches the total in 2007.
It's also far below the 140 or so that lived here before dozens were captured for aquariums and parks in the 1960s and early '70s.
A 20 percent drop in their numbers in the late 1990s, blamed by many on pollution and dwindling salmon stocks, led to their listing as an endangered species. Experts estimate a long-term steady population of about 200 would be needed to take them off the list.
Experts caution that young orcas have a rough life - commonly, about 50 percent die in their first year - and that one good year isn't a recovery. Critical to their long-term survival, they say, will be cleaning up the marine environment and eliminating the toxic chemicals that collect in the whales' bodies, and restoring the region's once-massive salmon runs.
Still, Balcomb said: "I'm just optimistic that this year's bumper crop of babies will prove to be their investment in the future. And we should invest in the food resources for them and for us.
"We like salmon, too."
zaterdag 9 januari 2010
woensdag 6 januari 2010
Two killer whale types found in UK waters
Scientists have revealed that there is not one but two types of killer whale living in UK waters.
Each differs in its appearance and diet, with males of one type being almost two metres longer than the other.
The killer whales could be at an early stage of becoming two separate species, the researchers say.
The international group of scientists has published its results in the journal Molecular Ecology.
"It's exciting to think about two very different types of killer whale in the waters around Britain," says Dr Andy Foote from the University of Aberdeen, UK, who undertook the study.
"Killer whales aren't really a species that we think of as being a regular visitor to Britain, but in fact we have two forms of these killer whales in our waters," he told the BBC.
Scientists have found different forms of killer whale that occupy particular niches in the Pacific and the Antarctic, but this is the first time that they have been described in the North Atlantic.
Dr Andy Foote undertook the study along with colleagues from universities and museums in Denmark and the UK.
Killer whales (Orcinus orca), otherwise called orcas, live in family groups called pods.
As the largest member of the dolphin family, killer whales are known for their intelligence and range of hunting behaviours.
Tooth work
There was very little prior to this study to suggest that different types of killer whale would be found in the North Atlantic.
However, Dr Foote and colleagues studied teeth from remains of killer whales stranded over the past 200 years and found a difference in tooth wear.
"We found that one form, which we call 'type 1' had severely worn teeth in all adult specimens," explains Dr Foote.
"The other form, 'type 2', had virtually no tooth wear even in the largest adults."
In the wild, killer whales that "suck up" herring and mackerel display this tooth wear.
Knowing this, the researchers suspected a difference in diet and ecological niche between the two groups.
Dolphin predator
Using stable isotope analysis that gives clues to the orcas' diet, the scientists found that type 1 is a generalist feeder, consuming fish and seals.
Type 2, on the other hand, is a specialist feeder that scientists suspect exclusively feeds on marine mammals such as small dolphins and whales.
This specialisation for alternative ecological niches has also resulted in a difference in shape and appearance.
"The two types also differed in length, with type 2 adult males being almost two metres larger than types 1 males," Dr Foote says.
The researchers also found that colour, pattern and number of teeth vary between the groups.
Dr Foote says the fish feeding type 1 killer whales are found across the North East Atlantic and around Britain.
The cetacean hunting type 2 killer whales are regularly seen off the west coast of Scotland and Ireland.
New species
Genetic analysis indicates the two types belong to two different populations.
"Type 1 specimens were from closely related populations, but the type 2 whales were more closely related to a group of Antarctic killer whales," Dr Foote explains.
Comparing the findings with studies on killer whales around the world shows that killer whales have radiated to fill different ecological niches.
"It's similar to how Darwin's finches have adapted to different ecological roles in the Galapagos, but on a larger scale," Dr Foote notes.
He suggests this could be an important discovery for the future of the animals.
"They seem to have occupied completely different ecological niches and have started to diverge morphologically. This divergence may eventually lead to the two types becoming different species."
He also recommends the two types be considered "evolutionary significant units" and monitored separately in order to more effectively conserve one of the oceans most charismatic animals.
Each differs in its appearance and diet, with males of one type being almost two metres longer than the other.
The killer whales could be at an early stage of becoming two separate species, the researchers say.
The international group of scientists has published its results in the journal Molecular Ecology.
"It's exciting to think about two very different types of killer whale in the waters around Britain," says Dr Andy Foote from the University of Aberdeen, UK, who undertook the study.
"Killer whales aren't really a species that we think of as being a regular visitor to Britain, but in fact we have two forms of these killer whales in our waters," he told the BBC.
Scientists have found different forms of killer whale that occupy particular niches in the Pacific and the Antarctic, but this is the first time that they have been described in the North Atlantic.
Dr Andy Foote undertook the study along with colleagues from universities and museums in Denmark and the UK.
Killer whales (Orcinus orca), otherwise called orcas, live in family groups called pods.
As the largest member of the dolphin family, killer whales are known for their intelligence and range of hunting behaviours.
Tooth work
There was very little prior to this study to suggest that different types of killer whale would be found in the North Atlantic.
However, Dr Foote and colleagues studied teeth from remains of killer whales stranded over the past 200 years and found a difference in tooth wear.
"We found that one form, which we call 'type 1' had severely worn teeth in all adult specimens," explains Dr Foote.
"The other form, 'type 2', had virtually no tooth wear even in the largest adults."
In the wild, killer whales that "suck up" herring and mackerel display this tooth wear.
Knowing this, the researchers suspected a difference in diet and ecological niche between the two groups.
Dolphin predator
Using stable isotope analysis that gives clues to the orcas' diet, the scientists found that type 1 is a generalist feeder, consuming fish and seals.
Type 2, on the other hand, is a specialist feeder that scientists suspect exclusively feeds on marine mammals such as small dolphins and whales.
This specialisation for alternative ecological niches has also resulted in a difference in shape and appearance.
"The two types also differed in length, with type 2 adult males being almost two metres larger than types 1 males," Dr Foote says.
The researchers also found that colour, pattern and number of teeth vary between the groups.
Dr Foote says the fish feeding type 1 killer whales are found across the North East Atlantic and around Britain.
The cetacean hunting type 2 killer whales are regularly seen off the west coast of Scotland and Ireland.
New species
Genetic analysis indicates the two types belong to two different populations.
"Type 1 specimens were from closely related populations, but the type 2 whales were more closely related to a group of Antarctic killer whales," Dr Foote explains.
Comparing the findings with studies on killer whales around the world shows that killer whales have radiated to fill different ecological niches.
"It's similar to how Darwin's finches have adapted to different ecological roles in the Galapagos, but on a larger scale," Dr Foote notes.
He suggests this could be an important discovery for the future of the animals.
"They seem to have occupied completely different ecological niches and have started to diverge morphologically. This divergence may eventually lead to the two types becoming different species."
He also recommends the two types be considered "evolutionary significant units" and monitored separately in order to more effectively conserve one of the oceans most charismatic animals.
maandag 4 januari 2010
J47 born to J35
January 4th, 2010
Annual Southern Resident Killer Whale population count reported to US National Marine Fisheries Service.
The Endangered Southern Resident Killer Whale (SRKW) population increased in 2009 to 87 individuals as of December 31, 2009, a net increase of two during a year in which three resident whales are missing and five were born. Three of the new babies were born into J pod, the most frequently observed of the three pods (J, K, and L) that frequent the Pacific Northwest inland marine waters of the Salish Sea. No sooner had the census report been made to the government than another new baby killer whale appeared in J pod, this one to a twelve year old female on 3 January 2010! For the time being, that means the SRKW population is back up to 88! We are optimistic that this “baby boom” in J pod represents a comeback for the resident population that went into steep decline in the mid 1990’s. Now, their survival and continued population recovery depends upon sufficient food supplies (wild salmon, particularly Chinook) in future years in this region. The whales are traveling as far as California and Haida Gwai (Queen Charlotte Islands) searching for these nutritious fish, but they keep coming back to the Salish Sea. If the whales could talk to us, they would probably say that our effort to promote wild salmon recovery in the Pacific Northwest is good for all of us, so lets do all that we can. And, lets clean up the pollution, too, so we can all eat healthy fish.
Annual Southern Resident Killer Whale population count reported to US National Marine Fisheries Service.
The Endangered Southern Resident Killer Whale (SRKW) population increased in 2009 to 87 individuals as of December 31, 2009, a net increase of two during a year in which three resident whales are missing and five were born. Three of the new babies were born into J pod, the most frequently observed of the three pods (J, K, and L) that frequent the Pacific Northwest inland marine waters of the Salish Sea. No sooner had the census report been made to the government than another new baby killer whale appeared in J pod, this one to a twelve year old female on 3 January 2010! For the time being, that means the SRKW population is back up to 88! We are optimistic that this “baby boom” in J pod represents a comeback for the resident population that went into steep decline in the mid 1990’s. Now, their survival and continued population recovery depends upon sufficient food supplies (wild salmon, particularly Chinook) in future years in this region. The whales are traveling as far as California and Haida Gwai (Queen Charlotte Islands) searching for these nutritious fish, but they keep coming back to the Salish Sea. If the whales could talk to us, they would probably say that our effort to promote wild salmon recovery in the Pacific Northwest is good for all of us, so lets do all that we can. And, lets clean up the pollution, too, so we can all eat healthy fish.
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