WASHINGTON – Watch out, marine mammals. Here come the California coastal fireworks.

It might be time to split.

Pitting patriotic displays against species protection, federal regulators on Tuesday gave the green light to July Fourth fireworks shows along the San Luis Obispo, Monterey and Santa Cruz county coasts.

The pyrotechnics are popular among audiences, bothersome for harbor seals and California sea lions and proof of how National Marine Fisheries Service officials can hold the key to coastal use.

"Some folks push back," Monica DeAngelis, a marine biologist with the federal agency's Long Beach office, said of the permit negotiations, "but there's give and take, and everybody generally leaves the table satisfied."

Potentially, officials estimate, 6,170 California sea lions and 1,065 harbor seals might be bothered by the fireworks' noise and fallout. None is expected to be killed or injured.

Still, the disturbances are serious enough to count as "harassment" under federal environmental law. Harassment means "any act of torment, pursuit or annoyance" that can disrupt animal behavior. It's a no-no.

In particular, past fireworks have temporarily driven marine mammals away from their favorite haul-out sites, where they lounge around and forage.

"The loud sound bursts and pressure waves created by the exploding shells appear to cause more wildlife disturbance than the illumination effects," a 2002 federal study noted. "As the fireworks presentation progresses, most marine mammals and birds generally evacuate the impact area."

Because of when they occur, the approved fireworks displays do not disturb the marine mammal breeding that also occurs at haul-out sites.

A separate study conducted for the Walt Disney Corp. found that Florida fireworks displays left detectable but negligible and apparently harmless amounts of barium, strontium and antimony in nearby waterways.

In theory, fireworks operators or anybody else engaged in potentially disruptive coastal business could charge ahead without a permit. The problem, DeAngelis said, is that "then there's a risk of breaking the law" if protected mammals are harassed.

The 20 fireworks displays authorized Tuesday will range along the California coast from Santa Cruz in the north to Cambria in the south. The fireworks over Moonstone Beach at Cambria's Shamel Park, for instance, are estimated as likely to bother about 50 California sea lions and 60 harbor seals.

The entire region covered by the fireworks permit adjoins the Monterey Bay National Marine Sanctuary, a 6,094-square-mile expanse that was the first of its kind established along an urban shoreline. The juxtaposition forces regulators to juggle conflicting priorities.

"In Central California, marine venues are the preferred setting for fireworks in order to optimize public access and avoid the fire hazard associated with terrestrial display sites," National Marine Fisheries Service officials noted Tuesday.

At the same time, the Marine Mammal Protection Act compels officials to shield the likes of sea lions from harm. Conflicts get resolved with meetings and paperwork.

The Monterey Bay National Marine Sanctuary, for instance, filed a 16-page application for the harassment permits used for fireworks. Sanctuary officials consulted state and university biologists, local residents and academic papers.

Even more elaborate harassment applications have been filed to cover drilling surveys in Alaska's Chukchi Sea, rocket launches from California's Vandenberg Air Force Base and a proposed liquefied natural gas port along the Gulf Coast of Florida, among others.

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Call Michael Doyle, Bee Washington Bureau, (202) 383-0006.

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