Biologists will release a gray seal in the Atlantic Ocean for the second time after it was found swimming in an upstate canal last week.

The Riverhead Foundation for Marine Research and Preservation picked up the male seal from Robert Moses State Park in April, treated his injuries and then released him in the Atlantic on July 15. About two weeks later, researchers began hearing reports of a seal in the Champlain Canal in upstate Waterford — later determined to be the same seal they had released.

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The foundation said the seal was contained when state officials closed off and began to drain Lock 1 for maintenance. A group of biologists went to retrieve the juvenile male and read his yellow flipper ID tag on Friday.

Biologists said he appeared to have traveled up the Hudson River after his release. The seal was taken back to the foundation’s Riverhead facility and evaluated.

He is scheduled to be released at Ponquogue Beach in Hampton Bays at 1 p.m. Thursday.