Orca Network News - January, 2011
the Southern Resident orcas,
orcas worldwide, and their habitats
January 1, 2011 through January 31, 2011.
January 30, 2011 (The Guardian)
New research suggests that whales use their sophisticated communication techniques to develop distinct and separate cultures. Biologist Hal Whitehead and writer and self-confessed 'whalehead' Philip Hoare discuss this new frontier
PH When I read about your hypothesis that whales have developed their own religion and that they have a sense of morality because of the way they interact with each other, I couldn't believe it. I think I am right in saying that their sonar, with which they communicate, is also used to hunt – I saw it myself in New Zealand when I watched a sperm whale use its sonar to stun kingfish at the surface to eat. But your notion is that these animals have the power to cause damage to one another, which is where they might develop a sense of morality as a social complex. Is that right?
HW Sperm whales have the most powerful sonar in the natural world. It is very directional and extremely powerful. To use the sonar effectively, you not only need to make a click, you need to hear it. Any ear damage would be very dangerous; as some people have said, a deaf whale is a dead whale. Whales have got to look after their ears. So it seems highly likely that if a sperm whale's sonar system were directed at another whale's ears, it would be very dangerous for the receiver.
Orcas find shark diet a real grind
January 20, 2011 (Nature)
Killer whales are notoriously picky eaters. Now one type of killer whale, or orca, has been found to dine on an unusual dish: shark. But these 'offshore' killer whales of the northeastern Pacific pay a high price for their tough-skinned preference — their teeth become worn right down to the gums.
The documenting of their unusual diet adds weight to the notion that the region's three orca lineages are separate species, which has implications for both future studies and conservation strategies.
Killer whales (Orcinus orca) have been seen hunting sharks on a one-off basis before (see video). "They can take pretty much whatever they want," says John Ford of the Pacific Biological Station in Nanaimo, British Columbia, whose team reports the new evidence in Aquatic Biology1. But it is unusual for these top predators to specialize in this fare. One other orca population in New Zealand is thought to prefer shark meat, although researchers don't have solid evidence.
'Dead fish swimming' virus may be hurting Pacific salmon
January 19, 2011 (Vancouver Sun)
Volcanic eruptions, giant squid and sea lice have all been invoked to explain the wild swings in one of Canada's most valuable fisheries.
Now scientists have raised the spectre of a mysterious virus killing huge numbers of Pacific salmon before they reach their spawning grounds.
"The mortality-related signature reflects a viral infection," a team of federal and university researchers reported Thursday in a study into the collapse of British Columbia's famed Fraser River sockeye runs.
Orca group wearing down their teeth on abrasive shark diet
January 18, 2011 (Vancouver Sun)
Marine scientists have discovered a mysterious population of killer whales off the B.C. coast that specialize in killing sharks -- to the detriment of their teeth.
This study, published in the journal Aquatic Biology, proves through DNA evidence that offshore killer whales prey on large Pacific sleeper sharks, whose skin is so abrasive that it is believed to be wearing the whales' teeth flat.
"It's exciting. It's been a detective hunt for so long," said John Ford, lead author of the study and senior research scientist with the federal Pacific Biological Station in Nanaimo.
Other potential prey of offshore killer whales includes salmon shark, blue shark and spiny dogfish, as well as related elasmobranch species such as skates and rays. They may also consume fish such as halibut, meaning their diet could overlap with resident killer whales.