A rare Pacific seahorse was recently caught on camera off the coast of Long Beach, California, much to the delight of prolific scuba diver Roger Hanson.

Hanson told weather.com that he originally spotted the fish earlier in the year while he was tending to his octopus garden in the Alamitos Bay (he describes himself as an "Octopop," helping maintain an artificial reef for California two-spot octopuses), but unfortunately, he had left his camera at home.

"I came again (the other day), and just happened to bring my camera, and bingo!" Hanson exclaimed. "There it was!"

The sighting is surprising, as the species's habitat is ordinarily south of San Diego, raising speculation that the seahorse was driven north by warm El Niño-fueled ocean circulation.

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"Seahorses in California are indeed unusual," Todd Gardner, marine biology professor and seahorse expert at Suffolk County Community College, told weather.com.

"I guess there are two reasons why an El Niño event would bring them there," he observed. "The first is that one species, Hippocampus ingens occurs in the waters of Mexico, not too far south of California, so increased water temperature associated with El Niño would allow them to temporarily expand their range to the north. Also, although seahorses are coastal fishes, it is not uncommon for them to be found drifting in the open ocean, attached to some seaweed or sea grass that has drifted far from shore. During an El Niño, the reversal of the Walker cell brings water from the western Pacific toward the American coastline, which could transport a seahorse from far away into California waters."

Although Hanson has been actively diving off the coast of California for many years, it's the first time he's seen a seahorse out in the wild. He previously had to fly overseas to witness one in its natural habitat.

"Before, I had to pay to see a seahorse," he said. "I got to see three and was charged $50. I had never seen one before on accident!"

Since retiring and moving to Long Beach, Hanson goes diving nearly everyday, and regularly provides upkeep to a manmade "underwater city" for octopuses, which he calls 'Littleville.' He has received recognition for his environmental work by Jean-Michel Cousteau, according to the Long Beach Press-Telegram .

Following the underwater discovery, Hanson suspects the seahorse he witnessed was pregnant, and says he is planning to be there on-hand to witness a sea birth.

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