April 25, 2010
Scientists have long thought that there may in fact be more than one species of killer whales due to behavior difference, small physical differences, and the animals' primary food source: fish or seals.
Scientists analyzed genetic samples from 139 killer whales and announced their findings in the journal Genome Research.
"The genetic makeup of mitochondria in killer whales, like other cetaceans, changes very little over time, which makes it difficult to detect any differentiation in recently evolved species without looking at the entire genome," explains Phillip Morin, lead author and geneticist at NOAA's Southwest Fisheries Science Center in La Jolla, California. "But by using a relatively new method called, 'highly parallel sequencing' to map the entire genome of the cell's mitochondria from a worldwide sample of killer whales, we were able to see clear differences among the species."
Morin and his team have identified at least three separate species of orca: a fish-eating species in Antarctica, another in Antarctica that primarily feeds on seals, and a third species that hunts marine mammals in the North Pacific. Further analysis may reveal that killer whales—long classified as a single species—are even more diverse than these three.
Unraveling the relationship between killer whale species will allow scientists a better understanding of these massive oceanic predators' ecology and how best to direct conservation efforts to make sure the diversity of killer whales is preserved.
Expedition to save world's rarest cetacean threatened by lack of funding
(02/11/2010) Little known beyond the waters of the Gulf of California, the world's smallest cetacean (a group including whales, dolphins, and porpoises) is hanging on by a thread. The vaquita—which in Spanish means 'little cow'—has recently gained the dubious distinction of not only being the world's smallest cetacean, but the also the world's rarest. In 2006 it was announced that the Yangtze river dolphin, or baiji, was likely extinct, and conservationists fear the Critically Endangered 'little cow' is next. An expedition for this year is set to identify vaquita individuals, but even this is threatened by lack of funding.
86 percent of dolphins and whales threatened by fishing nets
(02/07/2010) A new report from the United Nations Environment Program (UNEP) finds that almost 9 out of 10 toothed whales—including dolphins and porpoises—are threatened by entanglement and subsequent drowning from large-scale fishing operations equipment, such as gillnets, traps, longlines, and trawls. These operations threaten the highest percentage (86 percent) of the world's toothed whales.
No killing yet as season begins for dolphin slaughter made famous by The Cove
(09/02/2009) Due to the new documentary The Cove, the town of Taiji, Japan is suddenly famous, or perhaps more aptly, infamous. Winner of the documentary award at the Sundance Film Festival, the film uncovers a cove in Taiji where over two thousand dolphins are slaughtered every year due to the billion dollar dolphin entertainment industry. Their dolphin's meat is then labeled as fish and given to children for school lunches, even though as top level predators the meat is heavily tainted with mercury.