Marine Reserves: “protected should mean truly protected”, says marine scientist

National Geographic reports, 13th June 2017: New analysis of previous studies shows that biomassbiomass The amount of living matter. This is therefore a different measure to numbers of organisms. So, for example, there is much more biomass in 1 elephant than there is in 1000 fleas and there may be more biomass in 100 large cod than you would find in 150 small (because of over fishing) cod. of whole fish assemblages in marine reserves is, on average, 670 percent greater than in adjacent unprotected areas, and 343 percent greater than in 15 partially-protected marine protected areas (MPAs), according to an essay published in the ICES Journal of Marine Science.

Marine reserves also help restore the complexity of ecosystems through a chain of ecological effects (trophic cascades) once the abundance of large animals recovers sufficiently, say the authors, Enric Sala, National Geographic Society Explorer-in-Residence, and Sylvaine Giakoumi, Universite Cote d’Azur, in their opinion essay Food for Thought: No-take marine reserves are the most effective protected areas in the ocean. (Download a PDF)


Rainbow wrasses are common in shallow Mediterranean waters. Red coral used to grow also on shallow walls and overhangs in the Mediterranean, before historical overexploitation.
Photograph by Enric Sala.


There are significant additional benefits from a rigorous protection of portions of the ocean.

“Marine reserves may not be immune to the effects of climate change, but to date, reserves with complex ecosystems are more resilient than unprotected areas. Although marine reserves were conceived to protect ecosystems within their boundaries, they have also been shown to enhance local fisheries and create jobs and new incomes through ecotourism,” Sala and Giakoumi say in their essay.

National Geographic Voices interviewed Sala about the role of MPAs as an essential tool for reversing the global degradation of ocean life, and how that then enhances local fisheries and creates jobs and new incomes through ecotourism.

Read on to learn more about the importance of protecting the oceans and what you can do to help.

National Geographic Emerging Explorer and ecologist, Enric Sala.

What is the purpose and most significant finding of this new analysis?
We show that no-take marine reserves where fishing is prohibited have, on average, almost seven times more fish biomass (the total weight of fish per square mile) than unprotected areas nearby. But we also found that “marine protected areas” (MPAs) that allow fishing within their boundaries are not able to even double fish biomass. While these partially protected areas are useful for managing use conflicts, it is no-take reserves that are the most efficient in bringing back marine life and protecting ecosystems.

What are marine reserves designed to do, and how do they provide more than what they were initially designed for, as stated in the paper?
Marine reserves were initially designed to protect marine life within their boundaries, but over time we’ve discovered that they produce so many fish and other animals, that some of them spill over the reserve’s boundaries. That helps the local fishermen who now can catch more outside the reserve boundaries. And when the fish come back, the divers come in, bringing in more revenue and helping to create more jobs than fishing.

How successful are the reserves?
Reserves can be very successful, as shown in our research. As an example, there is a little marine reserve on the Costa Brava in the Mediterranean, the Medes Islands, that is only 1 square kilometre in size. But it contains one of the largest abundances of large fish in the Mediterranean, which attracts thousands of divers from all over Europe. That square kilometre brings in 12 million Euros per year through ecotourism.

Should artisanal or traditional fishing be allowed in marine reserves?
Marine reserves should be closed to fishing, so that they can bring marine life back and preserve it. Traditional fishing should be carried out in a sustainable way, but outside the reserves. Research shows that artisanal fishing does better next to reserves anyway.

What are the most significant challenges in proclaiming marine reserves and enforcing their protection?
Biggest challenge is opposition from the fishing industry, mainly because either they are not aware of the benefits of reserves to fishing, or because they opt for short-term economic gain at the expense of the resource they exploit. But I’ve met fishermen who were against reserves initially, but who now want more reserves, because they’re better off because of them.

How much of the ocean do you believe should still be set aside for marine reserves? Are there any specific areas that should be given high priority?
A study indicated that, on average, about 40 percent of the ocean should be protected to achieve ecological protection but also sustainability of fisheries. I think that we should protect half of the ocean, which according to another study would allow to catch the same amount of fish in the other half, fishing less.

It also should be made clear that protected should mean truly protected. No-take reserves are protected areas. MPAs that allow fishing, in my opinion, should not be called protected areas, but “managed areas”. And these managed areas should not count in the global tally of how much of the ocean is protected. Calling an area that allows fishing a “marine protected area” is like calling a timber concession (no matter how well managed) a “protected forest.”

How much of the ocean is protected now?
Only 3.5 percent of the ocean is under some type of protection, and less than 2 percent is in no-take marine reserves. Despite the recent increase in large MPAs worldwide, we are still short of the United Nations target of 10 percent of the ocean. So we have a lot of work to do.

What ultimately can the public do to help conserve the oceans?
Avoid single-use plastic such as straws and plastic bags, and eat less meat and more vegetables. And of course, if you eat fish, eat only fish that have a label of sustainability.

What is your current/next research project?
We continue to survey the most pristine places in the ocean and work to inspire leaders to protect them in large marine reserves. For updates on the project please see

Source: National Geographic, 13th June 2017. For further details, see


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