The mother orca snags a big chinook salmon, bolts for the surface and chomps it in two. She leaves half for her baby. It's a newly discovered behavior of Pacific Northwest killer whales, one that may help explain how young orcas survive when salmon runs are lean, marine scientists meeting in Seattle revealed Tuesday. In effect, the parents appear to be allowing themselves to starve at about the same rate as their children -- although father orcas give up far fewer fish than do the mothers. And this sharing may explain why orcas stay with their families for life.
However, scientists said, the salmon that nurture those baby orcas increasingly appear to be delivering a dose of chemicals that skew orcas' immune and reproductive systems -- chemicals the Washington Legislature recently refused to ban.
These fire-resistant chemicals, known as PBDEs or polybrominated diphenyl ethers, are still at much lower levels in the animals than the previous generation of fire-resistant chemicals, PCBs, or polychlorinated biphenyls. But the concentration of the new chemicals will surpass those of the old ones in 15 to 20 years, said Peter Ross of the Canadian Department of Fisheries and Oceans.
The two sets of long-lived chemicals in combination pack a one-two punch, Ross said in an interview Tuesday. "If you get that in a fetus, you may not see proper brain development," he said. "You could get adults that are quite diminished in a number of ways." The revelations came at a science conference sponsored by the National Marine Fisheries Service, which last year declared the orcas in need of protection under the Endangered Species Act and is now searching for ways to protect them.
EDIT
http://seattlepi.nwsource.com/local/265582_orca05.html
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
