The U.S. Navy is asking the National Marine Fisheries Service (NMFS) for another five-year permit to conduct sonar- focused training and testing, which will harm marine mammals and other sea life in waters off Southern California and Hawaii.

With its current permit expiring in December, a new one is needed to train crews in staged situations using passive and active sonar, by ship and by air. At a great distance, sonar can disrupt feeding and communication of marine mammals. At a close distance, it can cause deafness or death.

There’s no question that the Navy needs to pursue this training. Sonar is used to detect and locate mines and submarines, the latter which, officials say, are getting harder to find because of quieter, noise-reducing technologies used by various countries and potential rogue threats.

There are, however, valid questions regarding how and where training should be conducted. Before signing off on a new permit, NMFS — the federal agency responsible for stewardship of national marine resources — should require the Navy to further step up its efforts to protect vulnerable sea life.

The Navy estimates that training slated for the next five years could result in a total of nearly 8,000 cases of temporary hearing loss in whales, monk seals and dolphins. In addition, there would be millions of “harassment” incidents, defined as essential behavior disruption. That’s far too much injury.

David Henkin, an attorney for Earthjustice in Honolulu, has pointed out that while the Navy has proposed some limited measures to curb sonar and related explosives use around Hawaii island and Maui County, it has so far failed to protect vulnerable marine mammal populations around Kauai and Oahu.

That’s concerning since both islands have thriving populations of so-called resident marine mammals that call those waters home because they serve as a food oasis in the ocean’s vast food desert. To better comply with environmental obligations under the Marine Mammal Protection Act and the Endangered Species Act, the Navy should move more of its sonar-related training to the Pacific’s food desert areas.

So far, though, the Navy has balked at the idea of conducting exercises farther out to sea, regarding it as impractical and less cost-efficient. But it is a mitigation worth the balance, as it would more effectively shield sea life from harm.

Right now, shielding is dependent on the Navy’s trained lookouts that scan surface waters during training involving acoustic, explosive and physical disturbances. If they see any breaching animals, the action either stops, powers down or modifies to avoid harm.

But because the spotters cannot see underwater, this strategy is, obviously, flimsy. In a big ocean, large and small marine animals are easy to miss. Lookouts aboard vessels are surely hard-pressed to catch a glimpse of deep-diving whales.

Back in 2013, when the fisheries service approved the last five-year permit proposal, Earthjustice and other environmental groups filed a lawsuit challenging the federal agency’s decision to allow training that was essentially free of any limitation.

In a settlement reached in 2015, the Navy agreed to abide by some limits, such as a ban on sonar and related explosives training on the eastern side of Hawaii island and north of Molokai and Maui. It’s in place to safeguard endangered Hawaiian monk seals and small populations of toothed whales, including the endangered false killer whale.

Under that permit deal, the Navy estimated it could inadvertently kill 155 whales and dolphins off Hawaii and Southern California, mostly from explosives.

Moving forward, there’s no disputing that for the sake of combat- ready national security the Navy needs to develop and maintain expertise in sonar use training. But for the sake of reducing collateral damage among marine mammals and other species, it must establish and respect important safe havens.