Chemicals tainting orcas dinner

[n2doc]

Chemicals tainting orcas' dinner
More PBDEs seen; adults often share fish with young

By ROBERT McCLURE
P-I REPORTER

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.

more: http://seattlepi.nwsource.com/local/265582_orca05.html