On her first-ever scuba diving adventure on the colorful coral reefs and blue holes south of Eleuthera in the Bahamas, underwater photographer Maggie Martorell of Hollywood immediately noticed something was missing.

“Where are all the little tropical fish?” Martorell wanted to know.

The reef looked healthy; stands of mountainous star coral jutted up from the ocean floor, interspersed with tangled branches of staghorn. Soft corals, such as sea whips and sea fans, undulated with the gentle current. A few groupers swam around the entrance to a marine cave that descended into darkness in the middle of the reef tract.

But Martorell was alarmed by what she didn’t see — convict-striped sergeant majors busily patrolling the reef to protect their mass of lavender eggs; brightly hued parrotfish munching the thin coating of algae covering the coral; angelfish, gobies, surgeonfish and others meandering around, doing whatever it is they do in a typical day.

Then, as Martorell swam around with her camera, she saw a large lionfish sitting boldly outside a cavern. A few minutes later, she spotted another of the peppermint-striped predators, then another. They weren’t even trying to hide from the photographer and her fellow divers.

The same thing happened during Martorell’s second day of diving at another reef off Eleuthera. Lionfish were plentiful, but she had trouble finding other subjects to photograph.

Back on board the dive charterboat, Martorell and her companions talked about spearing the lionfish. But, without a special permit from the Bahamian government, scuba divers are not allowed to use spears; only breath-hold divers may hunt with the weapons. None of the occupants of the boat were skilled at holding their breath long enough to kill a fish in 50 feet of water, so they had no spearguns. And none of the guests — all tourists from the U.S. — had come prepared with heavy-duty plastic nets to catch the venomous invaders from the Pacific. So the lionfish were safe.

Lionfish — rarely seen in the South Atlantic, Gulf and Caribbean until about 10 years ago — can now be found in waters as shallow as a few inches in mangrove estuaries to more than 1,000 feet deep in the open sea. They mow down tropical reef fish like a Briggs & Stratton cuts a suburban lawn. According to Lad Akins of the Key Largo-based Reef Environmental and Education Foundation (REEF), divers are their primary predators — just as long as they take care to avoid the venomous spines sticking out from the fish’s back and undersides.

Organized derbies in the Bahamas and South Florida seem to be putting a dent in local lionfish populations, but those divers will never be able to kill the fish that inhabit waters too deep for standard scuba gear. Authorities concede the species can never be wiped out, but perhaps it can be controlled by persistent, local harvest. The Florida Fish and Wildlife Conservation Commission is making that easier: last week, the agency issued an executive order eliminating the requirement that harvesters possess a saltwater recreational fishing license to take lionfish by pole spear, Hawaiian sling, handheld net, or any of the dozens of devices sold on the Internet or at dive shops specifically designed to target lionfish.

Martorell’s Eleuthera experience was in sharp contrast to recent dives at several popular sites in the Upper Keys, where REEF has educated members of the dive industry and their customers on the importance of culling lionfish. And harvesters can obtain special permits from the Florida Keys National Marine Sanctuary to take lionfish from areas designated no-fishing zones. Commercial fishers who find lionfish in their traps sell them to local restaurants.

Friends of Martorell’s, diving at six different sites in Key Largo and Islamorada over a three-day period in July, encountered exactly one lionfish, which was swimming around the wreck of the Benwood off Key Largo. Their most enjoyable dive was at Horseshoe Reef where a curtain of glass minnows shape-shifted around and through a series of coral-encrusted caverns, chased by snook, black grouper, and mutton snapper. Despite numerous dark tunnels and crevices dotting the reef where lionfish like to hide, the exotics were absent.

“Local removal efforts through the divers and dive operators seem to be quite effective in keeping the numbers down at dived sites,” Akins wrote in an email. “We still get reports of a lot of [lionfish] where divers don’t go, but at least in some high-priority sites, the removals seem to be working.”

Outside the Keys, the lionfish body count is rising: about 80 divers harvested 1,043 during last Saturday’s one-day derby in Palm Beach County; 48 divers harvested 419 at a similar event in June off Fort Lauderdale. And a group of free divers, mostly from South Florida, brought in 345 of the target species at a “Lionfish Bash” earlier this summer in Bimini.

The bad news: there are still plenty of them around. The good news: they taste just like ... hogfish.