Environmental organizations sued the U.S. government yesterday for failing to grant protections under the Endangered Species Act to orcas in Washington state’s Puget Sound. The population of orcas in the region has declined almost 20 percent since 1996. Earlier this year, the National Marine Fisheries Service acknowledged that the region’s orcas were at risk of becoming extinct, but said the population was not biologically distinct and that neighboring whales could potentially repopulate the waters if the current whales died off. The NMFS denied endangered status to the orca population, offering only limited protection under a less stringent law. In response, People for Puget Sound, the Center for Biological Diversity, Friends of the San Juans, and several other groups filed suit, saying the Puget Sound population is genetically distinct and needs the stronger protection status to recover. Listing under the ESA would protect habitat critical to the orcas and require federal agencies to ensure that their actions do not interfere with the survival of the animals.