[LUM#8] Too Close, Human
Establishing marine reserves far from any human activity? A measure that may seem paradoxical but could well become a key tool in ocean conservation. At least, that is the conclusion of the latest major global study aimed at surveying the fish and shark populations found in coral reefs.
This study is surprising even to the leading experts. “When I received the data, I thought it was a joke. A bad joke,” says David Mouillot, an ecologist at the Marbec laboratory (Marine Biodiversity, Exploitation, and Conservation) and a member of the international consortium that conducted this major survey. The researchers observed 1,800 coral reefs, including 106 located in marine reserves, and found that only one-third are inhabited by top predators such as sharks.
Far from men
Sharks tend to settle far away from human activity: researchers found these large predators on only 1% of the reefs located near human settlements, compared to 59% on remote reefs. Not exactly the stuff of a new *Jaws* movie. “Sharks are particularly sensitive to the noise generated by human activities, not to mention the presence of nets in which they can become entangled.” All the more reason to retreat far from humans. Far from us.
Would common fish tolerate our presence better? Nothing could be less certain. If the results for the reserves located near our coasts remain positive, it is primarily, according to David Mouillot, because “the comparison between the population inside a reserve and the one found outside can only be positive, since there’s nothing left outside! It’s as if you had a 2 out of 20 and were comparing your score to someone who got a 0. You did twice as well, but you still have a 2.”
Significant human pressure
To assess the extent of human pressure on these reserves and determine their actual effectiveness, researchers compared their biomass with that of the world’s most isolated sites, such as Hawaii, the Chesterfield Islands, and the Chagos Archipelago. The results are clear: “The biomass in these reserves located near human settlements doesn’t hold a candle to that of these global reference sites. There is a gain, but the benefit is not huge compared to the performance of highly isolated sites or the most protected reserves.”
The issue, of course, is fishing. For while these reserves are certainly a step in the right direction, they represent only a tiny fraction of the total marine area. “As soon as the fish venture outside, they’re caught, which prevents the population inside the reserve from growing normally,” laments David Mouillot. In 2010, the Aichi Targets committed United Nations member states to placing 10% of their marine areas under protection by 2020. According to the researcher, this is still insufficient to combat overfishing.
Economic barrier
But then, how far should we go—or rather, how far should we not go—to rediscover this ocean untouched by human pressure? “Twelve hours of sailing! That’s the threshold beyond which the cost of diesel [about 1,000 euros] becomes prohibitive for fishermen and tourists. It’s an economic barrier.” David Mouillot, like other environmentalists, is actively campaigning for higher fuel prices and an end to fishing subsidies. “It’s a vicious cycle: the more we subsidize, the fewer fish there are; the fewer fish there are, the more we subsidize.”
The researcher also highlights the damage caused by recreational fishing and urges the public to give up this cultural practice: “It’s easy to pull out a fishing rod, yet we wouldn’t dream of killing a bird in our own backyard.”
Expand the reserves
So, following this study, is the rift between fish and humans now irreversible? Are the reserves near our coasts doomed? “No,” replies the researcher, “they remain entirely useful provided they are drastically expanded.” As for the isolated reserves—far from being useless or easy to manage— “our study shows that they are the only effective protection for top predators . They must therefore not be neglected under any circumstances.”
The Age of Plastic
From the cold seas of Greenland to the remote paradises of the Pacific, via the Mediterranean, microplastics are everywhere. Including in the samples that Delphine Bonnet, a researcher at the Marbec laboratory, collects off our coasts. “Worldwide, 206 kilograms of plastic are dumped into the ocean every second.” This massive pollution stems primarily from our daily activities on land: “We find plastic microbeads in toothpaste, cosmetics, the fibers of certain synthetic clothing, and cigarette butts.” These microplastics cannot be treated by current wastewater treatment plants and therefore end up in the sea. In collaboration with the Center for Functional and Evolutionary Ecology (CEFE), the researcher is trying to understand what roles these disruptors may play in the ecosystem and what solutions can be implemented to reduce their presence. “70% of the microplastics found in the ocean are single-use. We all share some responsibility for this. We need to change our consumption habits and move away from the reign of plastic.”
UM podcasts are now available on your favorite platform (Spotify, Deezer, Apple Podcasts, Amazon Music, etc.).