Deep-diving spearfishermen surfaced with a mystery last month south of Pacific Reef Light off North Key Largo.
"I was shocked when I saw it," Wayne Grammes said. "It’s an ugly-looking fish with a face on it that looks like a tripletail and a tail like a jewfish."
The 15-pound, 27-inch fish speared by Greg Caterino of Tavernier turned out to be a humpback grouper — a species native not to Pacific Reef but to the tropical Pacific Ocean off Asia.
"This is the equivalent of a hunter in North America finding a zebra," said Grammes, who was fishing Dec. 23 with Caterino.
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"We’ve seen the successful marine invasion of lionfish," Reef Environmental Education Foundation Project Director Lad Akins said this week. "We certainly do not want to see it happen again with another Pacific species."
Akins, a renowned expert in fish identification, confirmed the speared fish was a humpback grouper. With an array of black spots, it’s also known as a panther grouper.
"This is not the first time these have been sighted in Florida," Akins said. "There have been five or six reported as far back as the 1980s, but all from different parts of the state."
"The juveniles are really popular in the aquarium trade," Akins said. "It’s quite likely that this is released fish."
Young humpback grouper sport a brilliant white color with an attractive spray of black spots. But they outgrow most privately owned saltwater tanks — and cast a hungry eye on other tank fish. "Just like lionfish, they are carnivores," Akins said.
At 27 inches, the humpback grouper was nearly as large as they grow, Akins said.
Caterino and Grammes, a Miami-Dade resident and frequent Keys diver, were searching a deep ledge about 95 feet down when they saw what appeared to be a black grouper. After it was taken, it was apparent that it was not something local, Grammes said.
The humpback grouper bears a passing similarity to the marbled grouper, a native species that is considered rare.
"This could be only the tip of the iceberg," Grammes said. "Who knows how many are down there? This was in an area where not many people go."
Lionfish gained a foothold in the U.S. and Caribbean largely due to their prolific breeding and venomous spines that fend off predators.
Humpback grouper could lack defenses needed to become established, Akins said, "but we really don’t know."
Due to the possibility of mistaking a humpback for a protected native species, Akins said, people seeing one should report its location to REEF rather than harvest it. To find out how, go to www.reef.org.