The U.S. Navy is moving forward with a plan that will intensify its sonar use off Southern California and Hawaii.
The Navy announced its final action Monday, which comes after the National Marine Fisheries Service granted the Navy permits for its plans that will intensify sonar use in the Pacific Ocean over the next five years.
The military estimates the training and testing program could inadvertently kill 155 whales or dolphins off Hawaii and Southern California, mostly from explosives.
Environmentalists are suing NMFS to demand the Navy consider alternatives.
Earthjustice attorney David Henkin says the groups were hopeful, but not optimistic, the lawsuit would lead the Navy to look at a range of alternatives.
Navy officials estimate its activities would have a negligible impact on marine mammal populations.