Blog Tags: Killer Whales
On January 10, a recreational boater reported spotting the remains of an orca (killer whale) stranded on the shore. Three days later, scientists from the Canadian Ministry of Agriculture and Land and the University of Alaska-Fairbanks arrived to conduct a full necropsy to gain insight into why the creature had died.
The whale was identified as Yakat, the matriarch of the so-called A4 pod that spends most of its time in British Columbia’s Johnstone Strait. While the necropsy will not be able to provide conclusive cause of death, Yakat’s death will provide insight into what orcas choose to eat when their favorite meal—salmon—is scarce, and her very location already provides clues as to where she takes her pod in the winter months.
Yakat leaves two surviving daughters, Nahwitti (A56) and Skagit (A35), at least four grandchildren and two great-grandchildren, all belonging to Skagit. She also leaves behind Springer, her grand-niece and adopted daughter who brought attention to Yakat and her family when they generously adopted the orphaned whale in 2002 after it was rescued and released from a rehabilitation facility.
The Exxon Valdez is to date the worst oil spill to have occurred in US waters. It has been well studied and provided twenty years worth of information on how ecosystems recover from oil spills.
The researchers discovered that the two groups, which they have creatively dubbed "Type 1" and "Type 2" have different wear on their teeth, suggesting different diets and thus different ecological niches. Then, genetic analysis confirmed that the two types of killer whale belong to different populations.
The scientists compared the findings to how Darwin's finches adapted to fill unique ecological roles.
So what does this mean for the future of the North Atlantic killer whales? If Type 1 and Type 2 become separate species, they would require separate conservation monitoring efforts.
And if that happens, hopefully the powers that be will think of some catchier names for them.
New research out of Canada indicates that some killer whale populations prefer king (a.k.a. Chinook) salmon so much that the whales will actually die when salmon numbers fall. Here's the curious part: killer whales, as apex predators, have their pick of other fish or even other large marine mammals, but still some populations appear to be dependent upon king salmon as their primary food resource. Another study from Hawaii found that killer whales can identify king salmon even when they are swimming alongside Coho and Sockeye salmon. And even in the winter, when king salmon make up just 10 to 15 percent of the salmon in the water, killer whales use echolocation to pick out their favorite fish. That's some impressively picky eating. A recovering picky eater myself, I fully relate. And king salmon are undeniably delicious. Who can blame them? But suffering king salmon populations spell trouble for the orcas. The pollock industry catches enormous amounts of king salmon as bycatch. And due to the low populations, the 2008 king salmon fishing season was cancelled in Oregon and California, and again in 2009 in California. With king salmon lovers abound on land too, something's gotta give.
Happy Friday, all! This week in ocean news, ...The New York Times described the threats facing sea turtles who nest on Miami's popular beaches. ...New research indicates that because killer whales in the Puget Sound must raise their voices to be heard over the din of boats, they may be exhausting themselves as they try to find food. ...Thanks to the loss of Arctic sea ice, two German ships are poised to become the first to go from Asia to Europe in the Arctic waters north of Russia.
Orcas live and travel in pods, which are groups of ten to twenty animals – this is not new information. However, researchers in Russia recently spotted superpods, groups of up to 100 killer whales. These meetings last anywhere from a few hours to a half day and are characterized by common social behaviors – mating, flipper rubbing, synchronized swimming – but to a higher degree than typically observed. What do these social clubs mean and why do they matter? They may simply be another avenue to socialize. Since their large numbers may actually scare off prey, they don’t seem to be an effective way to hunt. Perhaps most importantly, they may be a chance for whales from different pods to meet up and check out potential mates. With calf mortality rates as high as 50 percent in the first six months, any research into understanding orca reproduction is critical in maintaining healthy populations.
Welcome to Whale Wednesday, the first ever hump(back) day feature devoted to cetaceans. I'm taking a cue from Oceans4Ever, the masters of alliterative weekly features, like Make a Difference Monday and Freaky Fish Friday. Hopefully this will become a semi-regular feature -- what's not to love about whales, after all? Today, three scintillating stories about cetaceans: 1. The Seattle Times reports on the first scientific review of the effort to reintegrate Keiko, the "Free Willy" orca, into the wild. The paper, which appears in the journal Marine Mammal Science, shows that while Keiko wasn't accepted by other orcas and had to be fed frozen fish until he died in 2003, he lived a longer life span than any other captive male orca. Turns out Willy's freedom was only possible on screen -- having been captured at the age of 2, he had been held in captivity too long to make it on his own.
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