Scientists are throwing a sex party for giant conchs in Florida

March 5, 2024:

The sex life of a conch is, for a snail, quite thrilling. In the spring and summer, the queen conch — a large, ornate species of marine snail — hunts for a mate in the warm, shallow waters of Florida and the Caribbean. Rather than slime along the ocean floor like many other mollusks do, conch (commonly pronounced “konk,” with a hard “k”) hop using a claw-shaped structure attached to their gooey innards. During mating season, conch will leap toward one another and pair up.

Things escalate from there.

“Have you seen a conch penis?” Andrew Kough, a marine biologist at the Shedd Aquarium in Chicago, asked me on the phone. (I had not.) “It’s insane.”

Positioned next to a female, shells touching, the male queen conch will extend a long, worm-like penis, also known as a verge, into her shell opening to deliver sperm. This can take many hours. Once they uncouple, the female will eventually lay her eggs on the seafloor in a crescent-shaped sac that looks a bit like dried ramen. A few days later, free-swimming baby conchs will hatch and float around for a while before settling in the sand, forming the next generation of queen conch.


A juvenile conch with its eyes poking out.
Curtesy of Shedd Aquarium

At least, that’s how it’s supposed to go.

In the last few decades, the sex lives of queen conchs have run into trouble. In Florida and other parts of the Caribbean, conchs are struggling to find mates, struggling to pair up, and thus failing to produce new conchs. Part of the problem is that the population is far smaller than it once was due to decades of overfishing and increasingly destructive hurricanes. That means they simply have trouble finding other conchs to mate with. Meanwhile, conchs in nearshore waters of the Florida Keys — affectionately referred to as the Conch Republic — are failing, for largely unknown reasons, to develop gonads, which are needed for sexual reproduction.

These problems are putting the future of queen conchs in danger. Earlier this year, the US listed them as federally threatened, meaning they could become at risk of extinction in the near future.

A queen conch in Grand Cayman, an island in the Cayman Islands.
Allison Bailey/SOPA Images/LightRocket via Getty Images

But there’s now some good news for sex-starved conchs. This spring, a team of scientists will gather up queen conchs in shallow waters off the Florida Keys, where they’re isolated and failing to breed, and move them farther offshore where there are healthier conch populations. The idea is to give these queen conchs a better shot at finding a mate and, in doing so, help them recover.

The project, led by the Florida Fish and Wildlife Conservation Commission (FWC), is an example of what it often takes to save imperiled species in a world changed by humans. Conchs are now so rare that putting an end to overfishing isn’t enough. To survive, they need scientists to play matchmaker.

Meet the ridiculously goofy, delightful queen conch

The spiraled shell of a queen conch is beautiful and elegant. The animal’s soft body, however, is sort of the opposite of that. It looks like a jumble of flesh onto which have been stuck two giant googly eyes.

Fixed to the end of tentacle-like stocks, those eyes poke out of the conch’s shell like a periscope from a submarine. Though cartoonish, they’re useful. Conchs are likely more visual than most other snails, according to Gabriel Delgado, a conch researcher, and they use these eyes — which have rods and cones, as do a human’s — to find mates and avoid predators.

The queen conch is one of several dozen conch species worldwide, all of which are moderately large to very large marine snails. They’re found in and around the Caribbean, where they play a valuable role in the ecosystem: Conchs eat algae that can otherwise smother coral. (They tend to hang out in groups, which is why Delgado, an associate researcher at FWC, sometimes describes them as “marine cows.”) Queen conchs also provide homes for critters including a small fish, known as the conchfish, that lives within their shells.

Queen conchs are also prized by humans. These snails not only have attractive shells that tourists love to buy but also protein-rich flesh that people love to eat. (It’s not uncommon to find conch on the menu in seafood restaurants across the country.) Plus, these animals are easy to collect: Conchs live in shallow water, and they can’t really put up a fight.

These traits helped turn queen conch into the second-largest fishery in the Caribbean — and ultimately led to their woes.

Overfishing is a problem, but it’s not the only one

Decades of fishing for conch in the Caribbean — much of which is exported to the US for restaurants — has massively depleted the ocean of these animals. “Overfishing has caused population collapses throughout the range of the conch, leaving adult densities below that which would indicate successful reproduction,” according to a 2022 assessment by the National Oceanic and Atmospheric Administration (NOAA).

In Florida, however, overfishing is largely a problem of the past. Before 1985, fishing queen conch caused the population to crash until it was “threatened with extermination,” as newspapers wrote at the time. But that year, in light of these declines, all conch fishing was banned. In the four decades since, the queen has been well protected.

Young conchs in a bed of seagrass.
Courtesy of Shedd Aquarium

Nonetheless, these animals haven’t recovered. The most recent estimate, from 2022, suggests there are roughly 126,000 adult conchs in the Keys, Delgado said. That’s below an estimate from the 1990s. Three populations in Florida have disappeared altogether, according to NOAA. On average, the density of the animals is too low “for successful reproduction to be maintained throughout the region and for Florida to have a healthy self-recruiting population,” NOAA says.

Absent fishing, the barrier to recovery is largely linked to climate: Superstorms bury the mollusks alive and ocean warming can mess with their physical development. Before Hurricane Irma struck the Keys, in the fall of 2017, FWC measured roughly 700,000 adult queen conchs across the island chain. That’s well above the number of animals when the fishing ban went into effect. After the storm, however, researchers counted half as many; they believe the hurricane buried conchs under sand, killing them. Hurricane Ian, which hit Florida in 2022, also knocked the population back, Delgado said.

Then there’s the breeding problem. Many of the conchs that hang out in shallow waters near shore in the Keys, and especially the females, are incapable of reproducing. They’re not properly developing gonads, organs that produce eggs and sperm, Delgado’s research shows. The current theory, Delgado said, is that the temperatures there are just too extreme. Because the water is so shallow, it gets very cold in the winter and increasingly hot in the summer (climate change is exacerbating marine heat waves). Scientists are still untangling just how that could be impairing their development.

This means that, near the shoreline, there are very few conchs that can successfully reproduce. Those that can have trouble finding a mate. Delgado says it’s as though there were an apocalypse and only a few people survived, each on a different continent. “They’re going to have a hard time finding each other,” he said.

A queen conch out of the water.
Courtesy of the Florida Fish and Wildlife Conservation Commission

If humans have caused this conch apocalypse, humans can also help.

A solution to help conchs mingle

While conchs near shore are reproductively challenged, those farther offshore — close to the coral reef — are doing much better. In some regions, there are dozens of conchs in close proximity. They’re able to find each other, breed, and make babies, Delgado said.

In the coming weeks, Delgado’s team plans to search for conchs in shallow waters in the central Florida Keys, with funding from the Fish and Wildlife Foundation of Florida, an environmental nonprofit. The scientists will tag those they find and relocate them to a healthier group offshore. It’s essentially like dropping individuals who are alone and isolated in the country into a big city. Deeper water offshore is also less prone to temperature extremes, Delgado said, which means the relocated conchs should not have trouble developing the gonads needed for reproduction.

Queen conch with its eyes pointing out.
Courtesy of Shed Aquarium

Delgado wants to find at least 200 conchs to relocate. If all goes to plan, each of those animals will find their match (or more likely matches) in their new home. The researchers will then monitor the reproduction of those snails.

This intervention is not, by itself, going to save Florida’s conchs. It’s more of a pilot project that will help scientists understand the value of relocation services in helping a species recover. If these efforts do grow the offshore conch community, the state may continue to help conch mate in the years to come, perhaps on a much larger scale — especially if climate change continues to disrupt their sex lives.

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