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A group of surfers had a whale of an encounter Tuesday while riding waves off the coast of Silver Strand State Beach near San Diego.

Daron Case, who surfs with a group every morning, captured the astounding moment he got up close with the massive marine mammal on his GoPro, telling NBC News he regularly brings his camera with him while hitting the water.

A southern California surfer has a close encounter with a 20-foot-long whale. Daron CaseFrom Subject Received Size Categories Collins, James (NBCUniversal) FW: Joaquin Track Update 11am 11:32 AM 3 MB / NBC News

The whale swam within a few feet of the group, and thanks to "unusually" clear water, Case was able to film the whale below the surface.

The crew, named after the Coronado Cays, where they live, surf in the area each morning. While they had not seen a whale before, sightings are not uncommon along California's coast.

Case, who also goes by the name Captain of the Cays, told NBC News via Facebook that the whale is a California gray whale, which are often spotted as they migrate south to Mexico.

Experts at the Birch Aquarium in San Diego told NBC San Diego that the whale appeared to be unhealthy.

Case confirmed that the creature "looked rather skinny," and barnacles can be seen on its body — a sign that indicates it moves slowly through the water.