Guardians of the Reef: The Rescue of Mexican Caribbean Corals

The waters of Puerto Morelos are usually calm. The movement of the sea resembles a large pool swimmers enjoy in this tourist destination located in the north of Quintana Roo.

From the front of the main port, about two kilometers away, you can see large waves breaking, losing strength as they come into contact with a reef barrier off the coast. 

Despite the calm waters, “you have to respect the sea”, says a fisherman standing at the edge of a wooden pier missing some of its boards, which were swallowed by the ocean during Hurricane Delta’s pass, back in October 2020. The iconic leaning lighthouse also preserves the memory of Hurricane Beulah’s violence, in 1967.

The calm waters are due to a reef barrier that provides containment for the beach, but who protects the reef when nature unleashes its fury?

Since 2018, in the National Reef Park of Puerto Morelos, a group of volunteers came together to rescue corals after storms or hurricanes.

They call themselves the Guardians of the Reef, a brigade made up mainly of biologists, local fishermen and divers, who seek to address the deterioration of the reef caused by human activity and climate change. 

In addition to coastal protection, the coral reef off the coast of Puerto Morelos is key to the community’s two main economic activities: fishing and tourism, according to María del Carmen García Rivas, director of the National Reef Park of Puerto Morelos, which was has been a protected natural area since 1991.

“With natural phenomena becoming more intense, ecosystems need help” adds García Rivas.

The brigade, which was created with the support of The Nature Conservancy, has undergone a training process focused on saving as many corals as possible, explains Aysha Carolina, a certified diver and the current coordinator of the group.

When a hurricane approaches, the reef guardians activate an immediate action protocol: first, they check for available members, then they identify the most vulnerable sites and fragile species, such as branching corals.

Once the hurricane passes, an initial survey is conducted to assess the damage and decide what actions to take. The most immediate response is to glue the larger coral fragments together with a special cement, so they can continue to grow and form the reef’s structure. 

Smaller fragments are collected and transferred to a marine nursery that has the ideal conditions for growth. There, they will develop and later be “planted” in the affected areas. 

A day of restoration with the Guardians of the Reef

It’s 9:30 am and the temperature has already reached 29℃. The brigade is rallying at Puerto Morelos main dock to carry out a “massive planting” of corals rescued after the passing of hurricanes Delta and Zeta, both in October 2020.

The divers, already dressed in their black diving suits, prepare their gear. Some walk barefoot along the boards of the pier. Others gather oxygen tanks, cement, a bathtub, a cooler with lunch - these types of journeys usually last over six hours - and another cooler filled with plastic grids. 

The engine starts, and the adventure begins. 

The fragments are located in La Ceiba nursery, one of three in the National Park. This is the first stop on the trip. 

Sitting starboard side, with fins in her feet and a tank on her back, Arcelia Romero lets her body fall backside into the sea: the others follow her example, carrying pruning tongs, a logbook and the plastic grids where they will place the corals. 

Juanfra Garcia, a diving and snorkeling guide at the National Park, works underwater, removing the encrusted sediment from the PVC structure where the coral pieces are cut and placed in the black plastic grids. 

Resulting from this task, Juanfra obtained 200 fragments, cutting them one by one, all while carrying an oxygen tank on his back.

Thirty-five minutes later, the team returns to the boat now with the plastic grist full of coral pieces. Luis, captain of the boat, places the corals in a cooler filled with seawater to protect them. 

Back in the boat, the brigade's divers take off their visors, smiling as they do. The midday sun indicates it’s time for them to move onto the “sowing” area.

The engine starts again and the bow breaks through the calm ocean. They are heading for Bocana Reef, a site populated mainly by corals of the Acropora family, commonly known as “elkhorn” and “staghorn”, with branching skeletons that can be seen in detail thanks to the clear water. 

To look at the reef through the snorkel mask is to flood the eyes with the vivid flashes of a kaleidoscope: the lapis lazuli colored fish, the iridescent yellows of algae, the sinuosities of the reef that is home, protection and sustenance of this ever flowing life: hundreds of fish, sponges and mollusks live in harmony within a dance of blue. 

Above water, on the boat, four volunteers begin working around a tub, preparing cement with adhesive in it that will be used to bind the coral fragments together. 

The cement is molded to form little balls of dough that are placed in bags tied with rubber bands and placed on racks.

The immersion begins again. One by one they fall backwards into the sea. The captain passes them the material: grids with cement, grids with corals and black brushes with thick bristles to clean the base where the fragments will be placed. 

Aysha Carolina is in charge of calling for these “restoration outings”, such as this one, and activating the action protocol in cases of weather related emergencies. She verifies attendance, assigns tasks, gives directions and keeps record on all the actions taken. 

María del Carmen García Rivas, director of this protected natural area, also participates as a member of the brigade. She takes a bag of cement and starts gluing coral fragments together on the seabed. 

She also explains that branching corals are the most vulnerable to violent waters, which are becoming more frequent with increasingly intense natural phenomena.

Key ecosystems at risk

According to Lorenzo Álvarez Filip, head of the Biodiversity and Reef Conservation Laboratory (BarcoLab) at the Limnology and Marine Sciences Institute in UNAM, to talk about corals is to delve into complex living beings. 

Corals are colonial animals formed by small organisms called polyps, relatives of jellyfish and anemone. Thousands of polyps stick together to form colonies, which in turn give structure to the coral, due to the calcium carbonate structure they create. Inside these small polyps live microalgae called zooxanthellae in perfect symbiosis (mutual aid relationship) with the cora. This minuscule algae is what gives color to the corals. 

According to him, corals are the main builders of the reef’s structure; those complex three-dimensional structures that function as marine habitats for a plethora of species as well as providers of environmental goods and services such as coastal protection. 

“Generally speaking, reefs are highly diverse ecosystems; they have large numbers of different organisms living in them; they are considered the most diverse ecosystems on the planet”, assures Álvarez. 

Biologist Arcelia Romero, also a member of the brigade, explains that corals have two forms of reproduction: sexual and asexual.

“Sexual is the one we all know, where two gametes, sperm and an egg fuse to create a new individual. Asexual has more to do with coral fragmentation. The fragments, which we also call ‘mother coral’ or ‘donor coral’, have the ability to regenerate; and, at the same time, those pieces can form a new genetically identical individual at a different site”, says Romero.

In this restoration effort, corals were reproduced asexually, that is, with fragments that broke off the larger corals during the hurricanes.

In the National Reef Park of Puerto Morelos, UNAM’s Limnology and Marine Sciences Institute and Regional Center for Aquaculture and Fisheries Research (Criap) are also testing assisted sexual reproduction for corals.

Romero indicates that, although it's a slower method, it's also necessary to have genetic variability among corals, to help them become more resistant to diseases and temperature changes.

Álvarez Filip points out that the Mexican Caribbean corals have suffered extensive deterioration in the last 50 years, which began when tourist infrastructure in that area started to develop. María del Carmen García, also indicates that among the main problems the corals face are poor wastewater treatment and bad practices by tourists visitors, such as the use of sunscreen. 

However, since 2018 matters have worsened. In mid-2018, Hard Coral Tissue Loss (SCTLD), a disease locally known as “white syndrome”, was detected for the first time in the Mexican Caribbean reefs. 

Two years later, this rare disease had wiped out over 40% of the 25 species coral population. According to BarcoLab’s data, some of these, such as the “pillar” coral (Dendrogyra cylindrus), are on the verge of local extinction. 

The restoration program carried out by the Guardians of the Reef has planted over 50,000 corals, says García Rivas.

For Álvarez Filip, restoration efforts are essential to help the reef. However, he emphasizes that losses, estimated in the millions, are far in excess of planting capacity. 

“In one year, probably, on this coast alone, more than 80 million corals died. When we talk about restoration actions we are talking about, at best, a few thousand planted corals”, he says. 

Hope unites them

During the restoration trip, the volunteers exchange anecdotes. 

– One time we saw a family of manatees. It was so cool! – says Aysha Carolina.

– I hope they show up again – adds Lara Virginia, another of the volunteers.

Aysha lists the three things needed to be part of the brigade: in-water skills for snorkeling and diving, commitment and dedication, and finally, love and respect for the sea.  

“This project means a lot to me. Love, lots and lots of love and respect for our mother ocean and all the marine life swimming in the depths”, shares Aysha, the brigade leader. 

Juanfra Garcia says that most of his time is spent at sea, working, volunteering or just having fun. 

“I practically depend on the reef. My whole life revolves around the reef. That's where the idea of joining the brigade comes from. And, well, the commitment to maintain the reef as healthy as we can, so we can continue working and leave a legacy for the next generations”, said Juanfra in an interview. 

It’s 2:00 pm. Exhausted after swimming for hours with a heavy tank on their backs, lunch -sandwiches and horchata- is shared along with cheerful conversations, as the bright tropical sky shines in their eyes. 

Suddenly, the sky turns gray, dark clouds form a compact mass that advances rapidly over the coast. Having finished the job, the captain starts the boat’s engine, heading quickly for the coast to avoid the forming squall. It’s useless: the sky showers the crew with cold needle-like raindrops. 

They make it back to the dock. As the storm rages, they anchor. Juanfra jokingly suggests the group jump back into the sea, where the water must be warmer than the freezing rain. The group joyfully follows him off the dock, joking and laughing as they go. 

Once the heavy rain has passed, the soaked volunteers unload the equipment, laughing again at the situation. 

Aysha assures them that what they do is worth doing. It's a ray of hope for the corals at National Reef Park of Puerto Morelos, who are facing increasingly adverse conditions. 

“The truth is that it's an honor and a source of pride, seeing all the effort we put into this has a positive outcome. When we get to the reef, we can see the coral is already of a certain size, that it has grown, it’s strong, it’s resilient, it’s shiny. This motivates us to continue.” concludes the coordinator of the Guardians of the Reef brigade. 

Listen to the podcast episode in Spanish broadcasted by Radio UNAM:

This story was produced with support from Internews' Earth Journalism Network. It was first published on November 10, 2023 in Corriente Alterna in Spanish and has been translated and lightly edited for length and clarity. The English translation was produced by Mariana Maytorena.

Banner image: Divers near coral nurseries / Credit: Alejandro Castro.