‘We need a wilder world, with wolves and sharks’

Marine biologist Enric Sala explains that predators are key to the functioning of the ecosystems that provide so many services to humans

Clemente Álvarez
Enric Sala
The marine ecologist Enric Sala.National Geographic

As a child growing up on the Mediterranean coast, in Spain’s Catalonia region, Enric Sala, 54, wanted to be a diver on the Calypso, the research vessel of the famous oceanographer Jacques Cousteau. Part of his dream came true, as he became a marine biologist and was able to dive underwater to do research. But after years of study in Spain and the United States, one fine day he realized that “what I was doing was writing the obituary of marine life.” He needed to stop watching it be destroyed and take action to try to prevent the destruction. It was then that he realized that there are still untouched places on the planet that not even Cousteau got to see, and he started organizing expeditions to these unique places with National Geographic. According to him, these trips are to make sure the sites are protected and to show how different life on Earth is when humans are not around. His book La naturaleza de la naturaleza (The nature of Nature) was recently released in Spanish. It’s an “accelerated biology course” in which he explains why it’s necessary to return to a wilder world and repopulate the Earth with predators such as wolves or sharks.

Question. Why are predators so important in an ecosystem?

Answer. Because they are the providers of life. We have the wrong idea about predators, we believe that they eat everything and that if we eliminate them the rest will recover, when the opposite is true. It is the predators that provide stability to ecosystems. There is the example of the wolves in Yellowstone. The park was running out of trees, it had riparian vegetation, the slopes of the rivers were crumbling, there were no trout, no otters, no amphibians… But when the wolves were reintroduced, they began to regulate the deer population, which caused the vegetation to recover, stabilizing the slopes of the rivers and creating habitats for fish, amphibians, and birds... It is the predator that ensures that the entire ecosystem is working.

Q. For an ecosystem to work, does fear have to be a factor?

A. Yes, an ecosystem is a landscape of fear. We have also seen it proven in some coral reefs in the Pacific where there is no fishing but many sharks. You don’t see as many fish there because they are hidden. This phenomenon is separate from the fear of predators that we may feel. But that landscape the sharks create, where species wait in hiding to feed, is what ensures that biodiversity flourishes.

Q. Predators like the wolf control the abundance of other species, but they don’t do away with them completely. Why is that so?

A. Because there are spaces where prey are safe from predators. Furthermore, in a natural ecosystem everything is limited by the number of plants there are; that determines the number of both herbivores and carnivores. There are times when the predator reduces the number of prey, but then this also reduces the population of the predator, which means that the number of prey increases again and the cycle resumes. It’s a dynamic cycle which maintains the number of predators and prey and allows both to coexist.

Q. Why doesn’t this hold true for humans, who do drive other species to extinction?

A. The problem with humans is that other species have no escape, no one escapes from us. Furthermore, we are not limited by the number of plants there are or by the amount of solar energy that reaches the Earth each day. To overexploit the present moment, we are using the necrosphere, the energy that plants stored in the past.

Q. In the book, you say that this is the explanation that the eminent ecologist Ramón Margalef gave you when you asked him the same question in college. Is that so?

A. I was lucky enough to study biology at the University of Barcelona when Professor Margalef still went in to his office and taught the odd class about plankton in Marine Biology, although he was already retired. When there was a question for which no one had an answer, Professor Margalef always came up with something.

Q. What do you think about the way some people still reject the wolf?

A. There are two types of people who reject the wolf: those who do not know the wolf and who, as part of the collective unconscious, continue to have an atavistic fear that these predators eat people when in fact they do not attack humans. And the people who live in the countryside, the ranchers, due to the damage to their livestock. But this is something that can technically be fixed by compensating for the loss of cattle.

Q. Ever since you were a child, on the beaches of Catalonia, your whole life has been closely linked to the sea. What does it feel like when you dive underwater?

A. The earthly world, with all its worries and burdens, completely disappears for me. It’s like I’m transported to another dimension. The water helps to forget about gravity and that has an absolutely healing effect. Jacques Cousteau said that when he started diving he felt like an angel.

Q. How is fishing altering this underwater world?

A. We are emptying the sea. In the Mediterranean, three quarters of the fish population is being overfished, we are taking them out faster than they can reproduce.

Q. At what point did you realize that your investigations were limiting you to “writing the obituary of marine life”?

A. At the University of California they pressured us to publish many scientific articles. One day, working on an article about how fishing was shortening food chains in the Gulf of California, I started thinking about the studies I had published that year and realized I didn’t want to spend my life writing research on how we’re destroying sea life. I thought I was just describing the problem, not helping to fix it. I felt a bit irresponsible. And I ran away.

Q. How does organizing expeditions to the last untouched areas of the planet help to solve the problem?

A. Although they tell you in college that the most important thing to make rational decisions is data, in reality, for political leaders or communities to decide to protect unique areas, they first have to fall in love with those places. And if we can’t get them to those places, then we have to get the places to them, through documentaries.

Q. What is “shifting baseline syndrome”?

A. It’s thinking that what’s natural to a place, its baseline, is what we saw the first time we arrived at a site. For me, what is natural in the Mediterranean is what I saw as a child: crystal clear water, with sea urchins, tiny algae and no big fish. But this gives us the wrong idea, because if we go back in time we find that life was much more abundant than that. It’s like memory loss.

Q. Are we turning the planet into a huge farm?

A. Exactly, 96% of the biomass of the planet’s mammals is us and our livestock. Only 4% are wild mammals.

Q. Why do we have to go back to a wilder world?

A. Because wildlife is what provides us with the oxygen we breathe, the clean water we drink, it protects cities from flooding... We need a wilder world, with wolves and sharks, because for everything to happen we need the big predators.

Q. How do you get that wilder world back?

A. It is achieved by protecting areas so that fishing or logging is not allowed in at least in 30% of the planet by 2030. It is achieved by restoring and rewilding areas that have been degraded. In Spain there are many lands that were once agricultural that have been abandoned and that are an opportunity to restore ecosystems with their predators. You also get that by eating less meat and more plants, because right now half of the world’s agriculture is dedicated to feeding livestock. If we consumed less meat we could free land, restore it and rewild it.

Q. What happens in an ecosystem when fishing is prohibited?

A. In Spain, less than 1% of the sea is totally protected from fishing, but we know that the protected areas in marine reserves, such as the Medes Islands or Cabo de Palos, are not only extraordinary, but they also help repopulate the surrounding areas. Fishermen are fishing more around those reserves, we should create hundreds of them.

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