In the Sea of Cortez, sharks are becoming ever scarcer. An alliance between conservationists and fishermen could be the solution to saving the ocean's apex predators.
After kilometres of desert, crossing the last mountain ridge before the Costa de Cabo Pulmo and catching sight of the colours of the Sea of Cortez is like drawing breath after a long dive. The northerly winds – known here as El Norte – sweep across kilometre-long beaches where small tourist and fishing boats wait for the chance to head out. Dozens of people, who have come from all over the world, gaze at the green and blue hues of what Jacques Cousteau – the world-renowned oceanographer – christened the aquarium of the world, and the moment your eyes drop below the surface it is not hard to understand why. Just a few metres from the shore, zebra moray eels, olive and green sea turtles, parrotfish and surgeonfish, sea lions and eagle rays are just some of the members of the "welcoming committee" for what, for many, will be the most thrilling dive of their lives. Yet in the depths of that sea, something is changing fast and a precious treasure risks disappearing forever.
The Gulf of California, also known as the Sea of Cortez, is an arm of the Pacific Ocean lying between the Baja California peninsula and the states of Sinaloa and Sonora in mainland Mexico. Here, more than two hundred volcanic islands of every size are home to dozens of different species of seabirds and giant Mexican cacti that, come evening, become a roost for turkey vultures. Underwater valleys and canyons create abyssal pools up to three kilometres deep. The immense nutrient richness of its waters encourages the proliferation of plankton, which in turn sustains an enormous variety and abundance of organisms, many of them migratory, that come to these waters to give birth and care for their young in the first months of life. Across the three distinct ecosystems of the Sea of Cortez live 36 species of marine mammals, 31 cetaceans, five of the world's seven sea turtle species, six thousand macro-invertebrates and more than nine hundred fish species, including 48 species of shark.
In recent years, however, most populations have been declining in both number and size. For sharks, the past 25 years have seen what can only be described as a true collapse. "The reason," explains James Ketchum, marine biologist and conservation director at Pelagios Kakunja, an organisation working in the Gulf of California for the protection and conservation of sharks, "is primarily overfishing." The very richness and abundance of marine life has, in fact, been this sea's undoing: over the past forty years it has been quite literally besieged by both industrial and artisanal fishing operators. Complicit in the slaughter was the Mexican government which, with very little foresight, handed out an excessive number of fishing licences in the 1990s, drawing fishing vessels from all over Mexico. But where does the catch end up? In the case of sharks, the meat is used mainly to supply the domestic food market. The fins, on the other hand, fetch a small fortune in China, the Asian giant that has turned a global treasure into a pointless gastronomic luxury. The species paying the heaviest price is one of the most emblematic of these waters: the scalloped hammerhead shark, which made these seas famous the world over in the 1980s and 1990s.
Nine nautical miles from the northern tip of the Espíritu Santo archipelago, off the bay of La Paz, lies an underwater seamount discovered in the late 1970s by Professor Peter Klimley of the University of California, Davis. "Until the 1990s in those waters," recalls James Ketchum, "it was possible to spot three to four hundred hammerhead sharks in a single dive." In practice, the people of La Paz were swimming in a gold mine that, once word got out, began attracting experts and tourists from every corner of the planet. Everyone wanted to see the strange hammer-headed shark and, to do so, they were willing to pay a great deal of money. However, the thirst for profit quickly attracted those who saw greater gains in a dead shark, and the treasure chest began slowly to empty. "Between 1997 and 1998, on a single dive I could see roughly a hundred hammerhead sharks, but by 2001 the number had dropped to five or six at most. Today, in the waters of the Sea of Cortez, we can say that the scalloped hammerhead shark is ecologically extinct."
Why is its disappearance a problem? And why does it matter even to someone living thousands of kilometres from these waters? "The shark," James Ketchum continues, "is an apex predator, and that means its presence guarantees the balance of ecosystems. A healthy sea is a sea capable of feeding everyone, everywhere on the planet." Its disappearance, by contrast, triggers an increase in mesopredators such as the red sea bream, which will be free to prey heavily on herbivorous fish like the scarids – a family that includes, for example, the parrotfish. The latter, known as the architects of the reef, feed on algae that compete with corals for light. It follows that if they disappear, algae will begin to proliferate and literally smother the reef. This is just one example of the cascading effects that the disappearance of sharks can cause. But an even more direct and visible effect is the one felt by the tourism sector and, consequently, the economy. The disappearance of hammerhead sharks has in fact reduced exponentially the earnings not only of the businesses running dives off La Paz but also of all the associated commercial activities: from restaurants to transport, from hotels to souvenir shops. It has been estimated that a shark caught in a fishing net is worth approximately 150 US dollars. A living shark, on the other hand, is capable of generating around 360,000 dollars a year. For the entire duration of its existence. In Mexico, it was the community of Cabo Pulmo that grasped this, investing since 1996 in tourism and transforming itself from a fishing community into one of experienced tourism operators. Here, a community of around two hundred inhabitants can count on an annual income from shark-related activities – strictly controlled and safe for both people and animals (cage diving, for example, is strictly prohibited) – of approximately 1.5 million dollars (around 1.42 million euros).
Sharks have lived on this planet for 450 million years. Their allure has shaped cinema and literature, as well as our relationship with the sea. It takes only a glance at its vastness to picture the apex predator moving silently through its waters, with those black, round eyes and an intelligence about which we still know far too little. Its disappearance would be an incalculable loss, the consequences of which are unimaginable even to science. Hope comes from an unlikely alliance: that between conservationists and fishermen. Both live off and for the sea and, in order to continue doing so, they know they must save the sharks. "Fishermen know the Sea of Cortez perfectly, as well as the creatures that live in it," explains James Ketchum. "They help us find the individuals we tag and monitor, and from this activity they receive an income alongside that of their normal work, which — precisely because of the loss of abundance in the Gulf of California — is becoming less and less profitable. The long-term goal is that those who wish to do so leave fishing behind and devote themselves to tourism."
While many communities are changing course with the help of experts and conservation organisations, the survival of sharks also depends on governments. Fortunately, a positive signal recently came from Panama, where the fourteenth meeting of the parties to the Convention on international trade in endangered species of wild fauna and flora (Convention on international trade in endangered species of wild fauna and flora – Cites) was held from 14 to 25 November. There, despite initial fears and uncertainties, pressure from civil society and dozens of organisations led governments to vote to extend protection to 54 species of requiem and hammerhead sharks, representing more than fifty per cent of the species at risk of extinction whose fins are currently traded. A hugely important step forward on the eve of Cop15, the conference on which the future of the planet's biodiversity, as we know it, depends.