What is the surprising and secret power of lobster pee? This may protect Florida's coral reefs

South Florida loves its lobsters, which means it loves to catch and eat them. But there is another, lesser-known species of lobster whose value extends beyond the plate.

The spotted lobster not only lives on coral reefs, it also protects them, notably in a special way. Spotted lobster urine appears to act as a repellent for coral predators, creating what a new study from the Florida Fish and Wildlife Conservation Commission describes as “a landscape of fear.”

This surprising discovery (who even knew lobster pee?) is just one of many fascinating facts emerging from FWC's studies of the role lobsters play in the marine food chain and the struggling reef system of the South Florida. Researchers also documented lobsters feeding on coral-damaging fireworms and, for the first time, observed lobsters eating a fish. In this case, it was an invasive lionfish that the state is trying to prevent from taking over the reefs.

The findings could help guide efforts to save and restore South Florida's reef, which has lost about 90 percent of its hard corals over the past 40 years – devastating damage caused by ocean temperatures driven by climate change. killing disease, pollution, boat anchors and a number of other factors.

“There's so much effort going into coral reefs right now to try to save them and restore them as best you can,” said Casey Butler, FWC's spiny lobster research program manager. “But is there a way to let you know that the biology of the system is working in your favor, so you don't have to do as much work?”

Mini-season goals

Lobsters make up a major part of Florida's commercial seafood industry, and the annual mini-season frenzy for recreational divers packs the boat ramps in Miami-Dade and Broward counties and fills hotel rooms in the Florida Keys.

The main target is the Caribbean spiny lobster, a species that migrates as it grows, moving from shallow coastal seagrass beds to shallow reefs and then deeper waters that provide shelter and food. But the FWC's studies have focused more on the spotted lobster, which appears to be the one doing most of the work when it comes to protecting reefs.

They actually start their lives on coral reefs and stay there, serving this coral-protecting role as part of a healthy reef ecosystem. There are no seasonal limits or regulations protecting spotted lobsters, other than the release of berried females, but they experience little fishing pressure and are only occasionally caught in traps or by divers.

“Spotted spiny lobsters are sort of knights in thorny armor, if you will. They’re enigmatic, but no one fishes for them,” Butler said. “So we don't have to worry that people will really lash out and say, 'Oh, you can't fish for lobsters anymore because of the coral reef.' No, that's not what we're saying.

Natural repellent

They carry out their work in several ways. A recent study suggests a previously unknown power of lobster pee as a predator repellent. Lobsters urinate frequently, and lab tests, Butler said, show that coral-eating snails don't like seawater containing lobster pee and tend to avoid areas where lobsters live. While spiny lobsters and rock lobsters produce prodigious volumes of urine, it is the rock lobster that appears to have the strongest natural deterrents, particularly when their feeding habits are taken into account. They tend to target coral predators more.

Based on these studies, Butler believes that simply protecting spotted lobsters on a reef could be a more beneficial conservation step than trying to eliminate snails or fireworms that feed on coral.

Last summer, Florida's coral reefs experienced the deadliest bleaching event in history, largely due to record water temperatures. And the numbers are no better this summer.

This historic warmth also unintentionally provided a new variable for studies of the state's lobster. Butler and the scientists found that lobsters from healthier reefs ate harmful predators like fireworms. But as reefs shrink and food options diminish, the spotted lobster may turn to herbivores that protect the corals, leaving the damaged reef even more vulnerable.

“Think of it like you want to go out and you say, 'Tonight I really want to go eat scallops and crab legs or something,' and that's what you wanted, but instead you found yourself at the Golden Corral and had to just realize what was available,” Butler said. “I think that's kind of what's happening as we move on from one. less degraded system to a more degraded system due to the evolution of our quality.”

Butler said the FWC hopes to eventually publish its findings in scientific journals.

The spotted lobster appetite study was funded by the Fish and Wildlife Foundation with a $37,000 grant to FWC.

FWF communications and events director Michelle Ashton said funding the work was a “no-brainer”. She said it was important to understand what happens when a reef is stressed and the cascading ripple effects through the food web.

“Identifying some of this ripple is fascinating,” Ashton said.