Reynolds Channel’s giant tourist might have seen enough.

The adolescent humpback whale seen swimming in the Nassau County channel for more than a week could not be located by the mariners who set out Saturday morning to herd it gently back to the Atlantic.

“Herding operations” will stand down, the Atlantic Marine Conservation Society said, adding it remains on standby for future reports.

“The team is optimistic that the whale has returned to open water, and will continue to work with local partners to monitor the whale population in New York’s coastal waters,” the nonprofit said in a statement.

The 28-foot “subadult” humpback might have joined a nearby pod that was spotted feeding off the coast of Long Beach, said Jennifer Goebel, spokeswoman for the National Oceanic and Atmospheric Administration.

Experts now are trying to match photos taken of four members of the Long Beach pod with pictures of the whale that was first spotted in Reynolds Channel on Nov. 10, and had not left as of Friday morning.

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Each whale’s flukes bear highly distinctive markings, experts said.

Why the humpback soloed so long in the channel, located just east of New York City, from Nassau’s East Rockaway Inlet to Point Lookout is — at least for the moment — unclear.

“Sometimes young animals like to explore different locations, I really couldn’t venture a guess as to what circumstances made it go into the channel,” Goebel said.

Humpback whales, once nearly hunted to extinction, can grow as long as 60 feet, eat 3,000 pounds of tiny crustaceans called krill a day, and live as long as half a century, experts said.

This summer, small pods were spotted in the Atlantic off Long Island’s southern coast, said Rob DiGiovanni, the Atlantic Marine Conservation Society’s chief scientist.

Boat strikes, fishing gear and pollution are among the whales’ chief threats, experts said.

The Atlantic is far cleaner than Reynolds Channel, where the Bay Park treatment plant pours 52 million gallons of treated sewage every day.

Though some humpback populations have increased enough to be delisted as an endangered species, they remain protected under the law.

NOAA is investigating the deaths of 41 humpback whales from 2016 through April, along the coast from Maine to North Carolina as an “unusual mortality event.” Ten of those whales had been struck by boats.

Saturday’s rescue attempt was a multiprong effort, including the U.S. Coast Guard, the state Department of Conservation, Nassau’s Marine Bureau and police department, the Town of Hempstead, North Carolina State University, the Wildlife Conservation Society, Operation Splash, Gotham Whale, The Nature Conservancy, and volunteers from NOAA and the International Fund for Animal Welfare, the society said. All boaters are asked to stay at least 100 feet away from any whales — and experts asked them to motor slowly.

Anyone who sees the whales in the area should call the nonprofit at 631-369-9829 or email sightings@amseas.org.