A conservation group says the federal government is failing to protect offshore areas along the U.S. West Coast to help endangered Puget Sound orcas.

The Center for Biological Diversity told the National Marine Fisheries Service Wednesday it will sue if the agency continues to delay in designating more marine waters where the whales would be protected.

The fish-eating mammals typically spend summers in Puget Sound and winters foraging along the coast. They have struggled due to lack of food, pollution and vessel disturbances. There are now just 76 orcas.

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The group asked the agency in 2014 to protect as "critical habitat" offshore waters along the coast from northwest Washington to Point Reyes, California.

A spokesman for NOAA Fisheries says the agency is moving ahead as quickly as it can and that the work remains a high priority.

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