A hopping queen conch can be a sight to behold on the sea floor: its outer shell disguised by green algae, looking more like a rock than the exuberant prized pink queen, suddenly hurdling itself forward.
Now scientists say that quirky behavior can also help save the threatened sea snails increasingly battered by overfishing, warming oceans and more intense hurricanes.
In a new study published this month, a team of scientists from Chicago’s Shedd Aquarium used conch hops to calculate just how much space an amorous herd of conch need to mate. They concluded smaller, no-take preserves may provide a more nimble way to protect them.
“ Our goal was to be able to provide something that is usable by communities,” said conch biologist Andy Kough, the study’s lead author. “Fishers, they of course know where the queen conch are. So this is a great way for them to be able to say, ‘Hey, there's a problem. We recognize it. Let's go out and protect this aggregation.’”
READ MORE: Helping queen conchs mate in the Florida Keys
Herds of sunset-colored queen conch once crowded flats and rubble fields near reefs across Florida before they were fished to near extinction. Florida banned conch fishing altogether in the 1980s, but their numbers continued to drop. In 2024, they were added to the Endangered Species List as threatened.
Conch mate the old-fashioned way. Rather than release sperm and eggs and hope for the best like many fish, conch need to find each other for hook-ups. That means they gather in patches, both to make reproduction easier and improve their odds for survival, which ironically can also make them a target for fishing.
“You're getting the most bang for your buck if you're harvesting an area with lots of adults,” Kough said. “So fishers have historically targeted areas with lots of animals, which then removes the reproductive stock.”
When the population plummeted, that left a lot of lonely conchs looking for love.
In considering how best to protect them, fishery managers in the past have focused on the numbers of conch in an aggregation, or density, and not their behavior. Koush suspected there was a more accurate strategy. So the Shedd team applied something scientists call the “movement ecology paradigm,” and took a closer look at how the one-legged conchs’ hop to calculate just how much time and space their pursuits require.
“We looked at this as a way of evaluating how that density threshold fits,” Kough said.
To do that, the team needed to count hops. So they devised a way to attach biologgers to the conch’s shell to track their movement.
”So they jump around on this giant foot with a sickle-shaped operculum at the end of it, bouncing from place to place,” Kough said, describing the hard covering on a conch’s foot that can also act as a trapdoor when the conch shrinks into its shell to avoid predators.
For science nerds, Kough says it’s the perfect way for using “accelerometry in the water, because you're not hurting the snail at all.”
Surprisingly, the team found that conch hop a lot more than you'd think. Hundreds of drift dives to locate aggregations also found nearly all successfully reproducing herds were no longer than about 360 yards. That’s a much smaller area than many marine preserves, which tend to draw opposition from the public. Two no-take fishing preserves in the Dry Tortugas measure about 50 and 150-square-miles. A decade ago, plans to help revive reef fish in Biscayne National Park with 16-square mile no-take zone failed after state officials opposed it. A smaller preserve is now being planned after the National Parks Conservation Association successfully sued.
Protecting naturally reproducing aggregations is also the only way scientists have so far documented success in increasing numbers. Unlike other marine animals, like coral and some species of fish, using lab-bred conch to increase populations off Florida and in other places has failed.
“There have been tremendous successes over the last four decades with breeding queen conch. It’s down to a science,” Kough said. “The hard part is translating that breeding into repopulation and it's that outplanting that has never had any success that's been documented.”
To have just one conch survive to adulthood, he said scientists concluded they’d need to outplant between two and 4,000 babies, “which is not economically feasible.”
In busy waters around Florida, moving quickly to protect a breeding herd can make the difference in their survival. With dredge work planned for Port Everglades, for example, scientists are closely watching a nearby queen conch aggregation. It is one of only two documented breeding herds in Florida.
Enter the movement ecology paradigm. What makes the approach attractive, Kough said, is that it can be site specific and managed by locals.
For Kough, who started out pursuing a career as a veterinarian and switched to conservation ecology after a professor gave him a job observing the behavior of breeding birds, the findings offer some rare good news.
”One of the things we were excited about with this study was the potential to make a generalization to enable marine managers, resource managers, to be able to quickly put into place a recommendation to protect animals in harm's way,” he said.
“It’s like a first look. You can improve upon it, of course, site to site. But it's just an easy first look to help scale these protections and make sure that conch are around for the next generation.”
