Ritchie Graves, a NOAA Fisheries Service biologist who makes sure federally owned dams are living up to their Endangered Species Act obligations not to kill too many salmon, said the survival rate for young salmon swimming downstream to the ocean has been higher than ever the past three years, hitting about 50 percent for sockeye.

MSN: Record numbers of sockeye salmon return to Northwest - US news - Environment | NBC News

Still, codfish aren't about to become an endangered species, according to Sam Rauch, head of the NOAA's fisheries service.

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"This is a Hobson's choice, " said Steve Murawski, chief science adviser for NOAA's fisheries unit and one of the officials working to assess the spill's environmental damage.

WSJ: Gauging Harm to Ecosystem Could Take Years