How to Save Sharks off Cuba s Coast and in the Gulf of Mexico [Slide Show]
Throughout 2011 researchers from the University of Havana prowled fishing docks in Cabañas and Cojimar on Cuba’s northwestern coast. The teams met returning fishing boats, noted the type and number of fish caught, and asked crews where they had fished, how long and what effort was involved. Oceanic whitetip sharks regularly appeared in catches, and fishermen reported hauling in smaller ones and using them as bait. Researchers say this could indicate the presence of a whitetip nursery area nearby.
So far, that is the only piece of good news from a widespread, collaborative effort by scientists and policy makers to fill in gaps in our knowledge of sharks in Cuban waters. That knowledge is needed to determine how to save these apex predators in the Gulf of Mexico as a whole. The regional population of Oceanic whitetips and other shark species may have declined by as much as 99 percent since the 1950s, according to Doug Rader, chief oceans scientist with the nonprofit advocacy group Environmental Defense Fund (EDF). Populations have plummeted in part because sharks are often swept up as incidental by-catch.
Researchers have documented at least 54 species of sharks in Cuban waters, many of them important to low-tech, small-scale fisheries. But shark fishermen are reporting decreases in their catches, likely due to the accidental capturing of sharks by boats targeting other species of fishes. Little historical data exist for Cuban fisheries, making it hard to compare targeted and untargeted shark catches over the long term. "We have to go on discussions with fishermen, which is helpful but not truly quantitative," says Robert Hueter, a shark researcher at Florida's Mote Marine Laboratory.
There also is little data about the presence of shark nurseries and the frequency of the species’s migration in Cuban waters.
This lack of dataspurred U.S., Cuban and Mexican scientists to launch the Trinational Initiative for Marine Science and Conservation in 2007. The group set six research priorities, including expanding knowledge of sharks in Cuban waters in order to support conservation decisions for the Gulf of Mexico and Caribbean. The ambitious effort currently involves scientists from the EDF, Mote Marine Laboratory, Mexico's El Colegio de la Frontera Sur, and the University of Havana's Center for Marine Research.
The port surveys are one part of their work. During a nine-day research cruise in February 2013 a multinational group of scientists aboard the Felipe Poey collected water, plankton and sediment samples on the south side of Cuba around Golfo de Batabano and Isla de Juventud. They also interviewed fishermen harvesting finfish, tuna, and lobster in the area (pdf). A key objective of the cruise was tagging sharks, but although researchers had estimated five to 10 sharks per 100 hooks cast, Hueter says, “We caught three sharks total, or 1.44 per 100 hooks set.” The low numbers as well as discussions with fishermen suggest that overfishing in the area has affected shark populations.
Port surveys planned later this year for Batabano and Jucaro Bay on the south coast may confirm these suspicions. Scientists will also look for evidence of another whitetip nursery—a possibility given the location’s ecological similarity to the nursery area on the north side of the island.
A cruise planned for the fall will explore the Jardines de la Reina archipelago and Golfo de Ana Maria, two popular ecotourism areas where researchers expect to tag higher numbers of sharks. The group will eventually compile tagging, observational data and port surveys to create a formal habitat classification system. The system will describe the distribution and abundance of sharks in Cuban waters to help determine their habitat needs, Rader says, an important first step toward protecting them. "Most scientists believe sharks are critical to the resilience and robustness of marine systems, and that one of the best ways to maintain a warming and acidifying marine environment is to rebuild robust shark populations," he adds.
Several studies have shown that removing these top predators can be devastating, affecting the entire food chain "the ecosystem as we knew it dies without sharks," Hueter says. As top predators, sharks control the density and behavior of their prey, indirectly affecting the abundance of species farther down the food chain—a trophic cascade. For example, too few sharks can result in too many large reef fish preying on smaller species that keep coral reef algae in check. As a result, the reef can become overwhelmed by algae, killing the coral.
The economy suffers as well. A study published in the May edition of Oryx noted the value of global shark catches is now $630 million and declining whereas shark ecotourism, which currently generates more than $314 million a year worldwide, is on the rise and will likely reach $780 million within 20 years. The authors concluded that protecting sharks would benefit a wide economic spectrum and help several species recover.
Last March the Convention on International Trade in Endangered Species added whitetip, scalloped, great, and smooth hammerhead sharks and porbeagle sharks to its Appendix II, effective September 14, 2013. International trade in products from these species after that date must be accompanied by CITES permits confirming the sharks are harvested sustainably and legally.
That could ease global pressure on these sharks.
Meanwhile in Cuba one of the trinational research initiative's goals is establishing a science-based sustainable shark fishery. Given the insufficient data, managing the fishery through prohibitions is difficult, according to Rader, who advocates instead programs that carefully track unintended shark mortality and create incentives for avoidance as well as better handling of animals to reduce such mortality.
One potential tool for sustainable fishing is "catch shares," which give every participating worker the right to take a percentage of a total allowable catch. Shareholders may fish for their percentage whenever they choose. A red snapper catch-share program in U.S. Gulf of Mexico waters cut the waste of nontargeted fish by 50 percent since 2006 whereas catch shares reduced wasted fish on the U.S. Pacific coast by 78 percent in one year and in New England by 77 percent, according to the EDF. The scientists acknowledge that any tool used will need to be compatible with Cuba's socialist system and its priority on of food security and jobs in this struggling economy.
One technique for protecting sharks has already taken hold in Cuba: the designation of marine protected areas (MPAs) and sanctuaries. The country has more than 100 MPAs proposed or in existence, the largest network in the Caribbean. Location and size of any new areas will be based on findings from current research initiatives.
Of course, MPAs only protect specific, limited locations. Some species of sharks are highly migratory, moving among feeding grounds based on season. Whitetips travel throughout the Gulf of Mexico, along the U.S. East Coast, into the Caribbean, and out into the Atlantic. Sharks tagged in MPAs have been found far outside the boundaries of those parks.
"The big-picture goal of this work is to develop a multinational, coordinated approach to managing fisheries for highly migratory species, including sharks," Hueter says. "You can't manage a species that moves around by developing procedures for sustainability in one part of its range, while it is subjected to unsustainable pressures in another part."
In addition to the difficulty of developing management techniques for a wide-ranging animal, the scientists face unique challenges conducting their research. Cuba has limited infrastructure and resources. University of Havana researchers can't just hop over to Cabañas whenever they need to—few have cars and fuel can be hard to come by. Also, scientists in the U.S. and Cuba find it challenging to communicate, as e-mail can be slow and sporadic. An American scientist may suggest a Web site resource to a colleague in Cuba only to discover Cubans can't access it. Travel restrictions imposed by both governments create delays, a forced flexibility familiar to Cubans. The U.S. government restricts U.S. scientists from training their Cuban counterparts but allows mutually beneficial exchanges of information, turning the normal process of collaboration into something more complex. A report in Oceanography in 2012 outlined these and other challenges, including funding restrictions that prevent U.S. scientists from using any government funds on any expenses related to the initiative. (This report also elaborates marine science in Cuba and other collaborative efforts.)
Field work is also hampered by complicated, time consuming processes to gain permission from the Cuban government to use global positioning systems and satellite tags. Instead, the researchers employ conventional fin tags bearing a number and instructions in English and Spanish about where to return a recovered tag. "All you get from those are point A to point B, and you might get back 3 percent of them," Hueter says. In contrast, a satellite tag shows the animal's movements from point of tagging through the last transmission, along with water temperature, depth and other data.
But the research challenges pale in comparison with the potential payoff, say those involved. "What we're really doing is developing a model in the Gulf of Mexico that can be exported to other areas of the world where stocks move throughout multiple jurisdictions, which is practically everywhere," Hueter says. "That's the greater importance of our work."
Cuba by the numbers:
4,800-plus kilometers of coastline
4,000-plus islets and keys
18 percent of Cuba's ocean shelf designated as protected area
10 percent annual increase in visitors to Cuba in the coming years; more should the U.S. embargo be lifted
54 species of sharks
300-plus species of birds
18,000 species of insects
38,000 species of crustaceans
1,500 species of mollusks
6,700 species of plants
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