ANCHORAGE The National Marine Fisheries Service has designated a small group of killer whales in Prince William Sound as depleted under the Marine Mammal Protection Act.
With the designation, the fisheries service, part of the National Oceanic and Atmospheric Administration, likely will begin work on a conservation plan for the group, called the AT-1 killer whales.
The conservation plan would seek the reason for the population decline which NOAA says still is unknown and find out if and how it can be stopped.
''Whether or not we are going to save this population and I have my doubts we need to look at why,'' said NOAA biologist Craig Matkin.
The group numbered 22 whales in 1984 and now stands at eight or fewer. Nine died during the 1989 Exxon Valdez spill, and five since then have died for unknown reasons, Matkin said.
Matkin said one factor could be an 80 percent population reduction in harbor seals, a food source, in Prince William Sound. Another clue could be the high levels of contaminants found in the whales' blubber, such as polychlorinated biphenyls, or PCBs, and DDT. Both are carried in the atmosphere to Alaska from Southeast Asia, Matkin said.
''It's potentially symptomatic of a larger problem that needs to be addressed,'' Matkin said. ''You can also look at it as the canary in the coal mine.''
The whale group had been considered part of a larger population of 346 transient killer whales in the eastern North Pacific. Prince William Sound and Kenai Fjords also are home to about 362 resident killer whales.
But the review completed by NOAA found a number of differences genetic, behavioral, ecological and management between the AT-1 group and other killer whales.
The Center for Biological Diversity and seven other environmental groups brought the killer whales to the attention of NOAA in 2002. Brent Plater, a staff attorney with the group, said Thursday that the ''depleted'' designation was a positive first step.
''Now that we have this population recognized as in deep trouble, we can roll up our sleeves and start working on recovery actions,'' Plater said.
Bridget Mansfield, a marine management specialist with NOAA, said the creation of a conservation plan would be public process. Not only would it seek to pinpoint the factors affecting the killer whales, but would also consider other species in the Prince William Sound including humans.
''We'd need to balance the cost how does it affect the environment, how does it affect people,'' Mansfield said.
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