Scientists recently circumnavigated Cuba over 53 days and 1,960 nautical miles to examine ocean species and coral reefs as a first step toward designing comprehensive marine management and conservation programs for the island nation.

The idea for El Bojeo, which means the circumnavigation in Spanish, surfaced two years ago when Tamara Figueredo, a Cuban environmental economist, and Fabián Pina Amargós, a University of Havana biologist, concluded Cuba needed an integral study of its marine resources.

“Very few studies even existed, and none had taken samples in a short period of time, using a common methodology with a single team of scientists,” says Pina, a member of the council that oversees the University of Havana’s science schools.

A multidisciplinary group of 24 Cuban scientists set out on July 18 from Júcaro, on the country’s southern coast. Traveling in a vessel usually used for diving and snorkeling tours, they navigated around the island counterclockwise, returning to Júcaro on Sept. 8. Along the way they examined 66 locations, gathering data on ocean temperatures and other conditions while collecting samples of sand, sediment, seawater, and marine life.

A media team aboard generated content to inform the public every day, connecting viewers with the marine environment and educating them on ocean conservation—a task project organizers viewed as a main aim.

The expedition drew support from international organizations and Cuban institutions associated with six different government ministries. Two U.S.-based conservation organizations, the Environmental Defense Fund (EDF) and the Wildlife Conservation Society (WCS), provided funding and technical support.

Participants said that overall, they felt heartened by what they had witnessed, says Pina, one of four coordinators of the project.

“Even though for various decades we have been in the midst of a natural crisis and most environmental news is negative, it is very encouraging that on almost all of the 23 coral reefs sampled, the fish and coral demonstrate nature’s resilience and capacity to flourish and provide the environmental services that humans need,” Pina says.

The expedition coincided with the warmest recorded summer in the Caribbean region, according to the U.S. National Oceanic and Atmospheric Administration (NOAA). This will help participants parse the direct impacts of climate change and species resilience.

“Most of the [seawater] temperature readings we took were above 30 degrees Celsius, and by the end of the expedition most of the Caribbean had been at least a degree above average temperatures for 12 weeks,” says Pina.

Eyes on the temperature

Temperatures above 28 degrees Celsius represent a hostile environment for coral, Pina notes; but he points out that it is not only high temperatures, but also their duration, that determines the severity of the impact.

When corals are stressed by changes in conditions they expel the symbiotic algae, zooxanthellae, which live in their tissues and give them their color. This causes the coral to turn completely white, giving the name to the phenomenon known as “coral bleaching.”

Corals are not necessarily killed by bleaching. The algae can return to their tissues. But bleaching stresses them, and the longer the adverse conditions continue, the greater the chances of mortality.

“We need to revisit before next summer to monitor the coral reefs where we found bleaching so we can compare where the coral demonstrated resilience and where it died following this year’s heat wave,” says Pina. He adds that the team hopes to present a preliminary report on its expedition in mid-2024.

Initial findings indicate Cuba’s marine ecosystem is in better condition than those elsewhere in the Caribbean, scientists say. “The state of the coral reefs is an indicator that the [Cuban marine] ecosystem as a whole is still relatively healthy,” says marine biologist Eduardo Boné, senior manager for the Environmental Defense Fund’s Cuba fisheries and oceans program. “In terms of biomass, large fish and sharks are not so abundant, but the population of medium fish is healthier, and small fish even more so.”

Adds Boné, who leads EDF work on sustainable fishing practices: “The good news is that in the biomass sampled, many of the fish are herbivores. These clean the coral and increase their resilience to bleaching.” He says the finding confirms that conservation programs must support fishing policies that promote ecosystem balance by safeguarding key contributors such as these herbivore fish, which play a “critical role in coral’s ability to reestablish itself.”

Less fertilizer a plus

Boné says the relatively healthy state of Cuba’s marine ecosystem could be due partly to the fact that the country’s socio-political and economic situation precludes the large-scale use of agricultural fertilizer, so runoff from the land does not overload coastal waters with nutrients.

Further, Cuba’s fishing industry still relies on relatively small vessels. While Cuba does experience overfishing, the absence of industrial-scale fishing puts less pressure on the biomass than is the case elsewhere in the region.

Cuba’s comparatively lower volumes of tourism and urbanization also likely play a role by ensuring that water pollution is a localized problem and large expanses of the island remain undeveloped. Experts say government conservation efforts have contributed too, among them an ambitious program of protected areas. Currently 25% of coastal waters and 4% of Cuba’s Exclusive Economic Zone (EEZ) fall under national protection, and the government aims to increase the latter share to 13%.

“The excess of biomass in Cuba’s protected areas contributes to improving conditions outside the perimeter of protected areas and benefits the rest of the Caribbean because of the spillover and connectivity,” says Boné. He notes the population of sharks in Jardines de la Reina, a national marine park in southeastern Cuba, is 18 times larger than the average for the Caribbean overall.

“[Cuba has] highly advanced fishing and marine science that have informed decisions for the benefit of the population and the environment,” Boné says. “Despite the socioeconomic crisis, political will has been a constant...Cuba’s conservation efforts are setting an example for other governments.”