HUNTINGTON BEACH (CBSLA) – Less than one week after a pipeline break sent tens of thousands of gallons of oil spilling into the ocean and washing up on Orange County beaches, the amount of wildlife impacted by one of the worst spills in recent Southern California history seems to have been lower than expected.

As the oil spill spreads across Orange County, a team of biologists from the University of California Santa Cruz and Tenera Consulting firm assess the overall biological habitat by counting and categorizing biodiversity of the Little Corona del Mar tide pools, part of the Crystal Cove State Marine Conservation Area on Oct. 6, 2021 in Newport Beach, Calif. (Allen J. Schaben /Los Angeles Times/Getty Images)

However, one biologist says the effect on the ecosystem could linger in the long-term.

As of Wednesday, 13 live oiled birds and two dead birds have been collected by rescue teams, according to the Oiled Wildlife Care Network.

These are a considerably lower number compared to massive oil spills in the past, when hundreds of birds were killed. However, wildlife biologist Barry Nerhus, president of Huntington Beach-based Endemic Environmental Services, an environmental consulting firm, says the worst is not over.

“There may still be some long-term effects locally if the oil stays in the wetlands,” Nerhus said.

According to Nerhus, the impact will likely travel through the food chain in what he describes as bioaccumulation.

“Most definitely it would affect the fish, and it would go into, potentially, our local fishery, if we’re eating that kind of fish, locally, that could be a health hazard,” Nerhus said.

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Nerhus notes that just because oil is not visible in many places, it doesn’t mean it’s not harming the food chain.

“Especially, this is fall migration, where a lot of birds from the Arctic Circle, Alaska, Canada and the Pacific Northwest are flying down to winter here. They’re literally flying as we speak to reside in our wetlands. So unbeknownst to them, they could be landing on oil slicks and feeding on water that’s relatively toxic,” Nerhus said.

Some have speculated that so few birds were injured because they had flown away during last weekend’s Pacific Airshow. Nerhus says with 97 percent of Southern California’s wetlands now gone, it isn’t likely the birds in the Bolsa Chica Wetlands and Santa Ana River Salt Marsh flew anywhere.

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“I don’t think there’s any information on a decrease in bird populations in wetlands when the air show happens,” Nerhus said. “Maybe there’s less flying activity at the time, but they’re still there. And there’s many endangered birds that reside in those wetlands that have no place else to live,” Nerhus said.

Nerhus said there was so much focus was on the cleanup, crews may have missed some of the birds in need. The California Department of Fish and Wildlife is now asking for volunteers to help spot injured birds. For information on how you can volunteer, click here.

The pipeline leak, which was reported Saturday morning off Huntington Beach, may have spilled anywhere up to 144,000 gallons of oil into the ocean waters. The spill occurred in federal waters at the Elly rig, about 4 1/2 miles off-shore. The rig and pipeline are owned by Houston-based Amplify Energy.

Federal authorities confirmed that a section of Amplify Energy’s oil pipeline was damaged and moved more than 100 feet along the ocean floor, an indication that a ship’s anchor may have caused the spill.

(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)