In May, Australia’s Great Barrier Reef Marine Park Authority published a report describing what Australian divers and snorkelers had known all summer: the reef had bleached, again. 2022’s ‘reef snapshot’ showed that 91% percent of coral surveyed this year had undergone some bleaching—the sixth mass-bleaching event since 1998.
Coral reefs are in peril; this, we know. But, while coral reefs support 25% of marine species and provide the food, income, and security of millions of people the truth is that our understanding of reefs is quite shallow. Literally. “Most people know about the beauty and perils of shallow coral reefs, but almost everything we know about them comes from the top third of their depth range,” explains Luiz Rocha, an ichthyologist (that is, a fish scientist) and curator at the California Academy of Sciences. Rocha is one of the world’s pre-eminent experts on mesophotic reef systems, the so-called ‘twilight zone’ of coral reefs that extend below the surface. “Because recreational SCUBA diving can only be done safely to about 45 meters in depth, scientists (and the public) know very little about what lives on the bottom two thirds of coral reefs. These deeper reefs are darker and colder, and exploring them requires extensive technical dive training. But when we get there, we see that they harbor a unique and still undescribed set of animals.”
Rocha first fell in love with coral reefs growing up in Brazil in the coastal town of João Pessoa. “I started snorkeling as soon as I could swim, and started diving as soon as I could hold the weight of a SCUBA cylinder,” Rocha says. He started collecting aquarium fish at home, and learning all he could about their homes. In the 1980s, the nearby Picãozinho was coming under threat from uncontrolled tourism, “a destruction that I saw with my own eyes,” he says. As a high school project, Rocha wrote a conservation proposal for the area. “So studying and protecting coral reefs was the only thing I ever saw myself doing,” he says.
Today, Rocha has spent more than 6,000 hours underwater across more than 70 scientific missions around the world, chiefly studying the twilight realm of the reefs’ mesophotic ecosystems. In the process, he has helped discover numerous species new to science, among them the Black Panther-inspired Vibranium fairy wrasse, Cirrhilabrus wakanda. “The thrill of discovery is hard to beat, and nothing compares to seeing a brand new species of fish for the first time. I really feel like someone exploring a brand new world,” Rocha says. “Sadly, the science of taxonomy—naming species—is not valued among scientists, but it is the cornerstone of biology. Without species names, we can’t do anything else. So contributing to this foundational work is very important.” (Rocha himself has had two species of reef named in his honour: Sparisoma rocha, a parrotfish, and Pempheris rochai, a sweeper fish.)
In 2021, Rocha received a Rolex Awards for Enterprise in order to further his research into our twilight reefs. Launched in 1976 to mark the 50th anniversary of the first waterproof watch, the Rolex Oyster, the awards supports and encourages the work of those who go above and beyond to safeguard and preserve our planet for the next generations.
“These deep reefs are poorly known by both scientists and the public, and the exposure my project is getting through Rolex is just amazing,” Rocha says.” Today a lot more people are aware of the existence of those reefs, and independent projects aimed at protecting them are starting everywhere we go.” Rocha has campaigned for better marine protected areas—and in particular, ensuring that they are not necessarily just large, but well designed and well policed.
As one of the global leaders in mesophotic reef research, Rocha has spent years tracking the changes to these crucial ecosystems. For example, the non-native venomous Lionfish has spread throughout the Caribbean in recent decades, after likely being released by humans in Florida. Similarly, Rocha has tracked the decline in groupers, which breed and grow in coral reefs, but have fallen prey to rampant over-fishing. Together with his colleagues at the California Academy of Sciences, Rocha has embarked on the Hope For Reefs project, an ambitious series of expeditions intended to rapidly increase our understanding of coral reefs, and how to save them.
In 2022—after two years of COVID-related delays—Rocha and his team embarked on an expedition to the Maldives, collaborating with Maldivian scientists to study never-before-seen mesophotic reefs in the Indian Ocean. “The wait was very frustrating, but it was worth it. We found eight new species of fish on our first trip, some of which look just spectacular!” By collecting genetic data, and analysing stomach contents, Rocha and his colleagues are beginning to understand the relationships between the fish in these deeper ecosystems, and how they relate with the reef above. “When it comes to deep reef science, we are just scratching the surface. Species discoveries are always super exciting, but there is much more we don’t know about those reefs,” Rocha says. “In the future we plan to study the community ecology (how species interact with each other) and evolution (how species are related to each other) at those depths much more, and that will be very exciting.”
As part of his research, Rocha has been a significant contributor to the International Union for Conservation of Nature (IUCN) Red List, which tracks data on endangered species. He has witnessed first hand the degradation of reefs due to pollution, anthropogenic climate-change, and excessive fishing and tourism. “Sadly, bleaching is also reaching deeper reefs. We don’t hear about it a lot because these reefs are not monitored, however, they are being impacted not only by bleaching, but also by many other human activities,” Rocha says. “For example, we see plastic trash in every dive we do—and keep in mind that for the most part, we are the first people to ever see those reefs.”
After all these years of seeing corals in decline—global, hard coral coverage declined by 13.5% between 2009 and 2018, according to the UN Environmental Programme—how does he stay optimistic? “I went to Bikini Atoll in 2006,” Rocha says. The site of former allied nuclear weapons tests was devastated during the Cold War, and has been abandoned by people ever since. “I really expected to see reefs that were completely devastated. But when I dove just outside of Bravo Crater—the crater created by the largest man-made explosion in the history of the planet—I saw the opposite: some of the most beautiful and thriving reefs I have ever seen! Because Bikini is still contaminated with radiation, human presence there is very limited, so the reefs recovered beautifully from the nuclear tests. This really gives me hope for the future of reefs: if given the chance, they do recover. In Bikini, the solution was to keep humans out. In other areas it can be just to stop overfishing, or decreasing pollution, or coral restoration.” By understanding these ecosystems, we can help to better understand the threats they face—and how to curb them. “And if we are successful, I am sure we can bring true hope for the long-term survival of coral reefs.”
To find out more about the Rolex Awards for Enterprise and Luiz Rocha, visit Rolex.org, or explore our Planet Pioneers series here.
This article was originally published by WIRED UK
