Opinion piece: Fully protected marine areas allow us to have our fish and eat them too

Enric Sala, National Geographic Explorer in Residence

Enric Sala is a former university professor who saw himself writing the obituary of ocean life, and quit academia to become a full-time conservationist as a National Geographic Explorer in Residence. He founded and leads Pristine Seas, a project that combines exploration, research and media to inspire country leaders to protect the last wild places in the ocean. To date, Pristine Seas has helped to create 27 of the largest marine reserves on the planet.

As a boy growing up on the Mediterranean coast of Spain, I never saw a big fish while swimming. They had been wiped out by decades, if not centuries, of fishing. Fast-forward a decade, and as a young marine biology student enrolled on a local diving course, I was taken to the Medes Islands off the coast of Catalonia, Spain, for my first dive at sea. The waters around the Medes Islands had been established as a no-take marine reserve three years before. On that dive I witnessed everything that had been missing in the sea of my childhood—a myriad of Mediterranean sea life: scorpionfish, dusky groupers, a school of sea bream, and even an octopus hiding amid the algal forest. That first dive changed my life.

I keenly followed the state of the Medes Islands Marine Reserve over the next decade, diving there every weekend. The gradual transformation I witnessed was exceptional: the Medes ecosystem, free from pressures from outside the reserve, flourished. Commercial fish—now free from fishing—boomed in number and size; fan mussels quickly repopulated the seagrass beds; and soft corals—red, white and yellow—recoloured the underwater seascape. This was all thanks to the protected status of the reserve, allowing marine life to bounce back.

Over the course of my career, and when discussing marine protected areas (MPAs), I’ve encountered individuals—from government officials to fisheries scientists—who ask about the impact of MPAs on the fishing industry and whether they negatively affect their businesses. Some go even further to argue that good fisheries management—to fish in a “sustainable” way that tries to balance ecological health and economic viability—would make protected areas unnecessary. But unfortunately, I haven’t been able to find a single sustainable fishery in my beloved Mediterranean, where over three-quarters of the target species are overfished or have collapsed.

In contrast, fully protected marine reserves where fishing and other damaging activities are banned universally yield a full range of benefits to climate, biodiversity and even local economies.

But some say that we can have “protected” areas with “sustainable” fishing within their boundaries, so everybody wins. The evidence, however, doesn’t support this theory. I have seen for myself that lightly or minimally protected areas have fewer and smaller fish than fully protected (no-take) areas. In fact, research shows that these “partially protected” areas are indistinguishable from unprotected areas. But in fully protected areas, the total biomass of fish is, on average, six times greater than that of unprotected areas nearby. And when the fish come back, they produce many benefits to people.

There are many examples from around the world showing that fully protected areas produce fish spillover—fish become so large that they produce a disproportionately large number of eggs which, together with movements of adult fish outside the protected areas, help replenish nearby unprotected areas. That new fish biomass outside the protected areas helps replenish local fisheries, increasing the catches of species, from small and sedentary (lobsters, scallops) to large and migratory (tuna). After only a few years of protection, we can see fishers reaping the benefits of this full protection. In other words, fully protected areas are an investment account, with a principal that we set aside that produces returns we can all enjoy—by watching inside the protected areas and by catching outside of them.

No one is allowed to walk into the Louvre and pick up any painting they fancy. And no one should be allowed to remove endangered wildlife from areas that we deem worthy of protection. Marine areas managed for responsible fishing are all good and necessary, but if we want to restore marine life in earnest and prevent the accelerating depletion of marine life and all the benefits it provides, we need to establish more no-take areas.

As world leaders gather in Spain, Greece and Cyprus this year for major discussions on our ocean, they must remember that the establishment of fully protected marine areas is justified not only by science, but also by economics. As of April 2023, less than 8% of the ocean has been designated or proposed as protected, and less than 3% is fully protected from fishing. To keep our ocean healthy and thriving, we need much more—at least 30% by 2030.