[LUM#3] Coral reefs in danger
They are under threat all over the world. How can we better preserve coral reefs, irreplaceable refuges for marine life? A scientific expedition provides some new ideas.
New Caledonia, Tonga Islands, French Polynesia: this is not a list of idyllic destinations for your next vacation, but rather the research sites for the Pristine project. In these dream islands, home to some of the planet's last remaining ocean refuges, a team of marine biologists has been diving to encounter a wealth of marine life. Their goal: to assess the health of coral ecosystems.
Protecting marine life
Because these havens of life are in danger. "The latest scientific reports are alarming: 75% of the world's reefs are now threatened, with 60% under direct and immediate threat. By 2050, this figure will rise to 100%," warns David Mouillot of the Marbec laboratory.
To protect marine life, we must first understand it. "Virtually untouched sites are valuable because they provide a reference point: we can use them to measure the state of biodiversity in the absence of any human intervention." This reference will then serve as a benchmark for measuring the impact of human presence around the world, as well as for measuring the effectiveness of marine protected areas.
While diving on the Acteon Islands in Polynesia, the Minerva Reefs in Tonga, and the archipelago of New Caledonia, researchers were amazed by what they found. Beneath the waves of the Pacific, they witnessed a forgotten spectacle... "Sharks galore, gigantic groupers, napoleon fish, humphead parrotfish: abundant life animates these seabeds. Some species that thrive here are endangered elsewhere," describes David Mouillot.
An extraordinary amount of biomass: more than one ton of fish per hectare. That's about 70% more than what can be found in other protected areas around the world. The difference is spectacular. Why this explosion of life? Or rather, why are fish so scarce in other protected areas?
Human, too human
For scientists working on the Pristine project, the answer is clear: human proximity is responsible for the disappearance of fish. This is a factor they have carefully measured. "Coral reefs are closer to humans than we thought. Half of the world's reefs are located less than 30 minutes away from a village or market... These reefs are therefore under very high pressure. As a result, 90% of large predators, such as tuna and sharks, have disappeared from these areas."
Only reefs that are sufficiently far away from human communities would be safe, according to the study, which sets the critical threshold at around 12 hours' travel time. However, such reefs are now very rare."Worldwide, barely 1% of coral reefs are located in safe areas, i.e., more than 12 hours away. This is the other major finding of the study: the rarity of these natural refuges. They are mainly found in the middle of the Indian Ocean and in the Pacific."
Western countries have a responsibility to protect these areas, which are vital for biodiversity. Most of these last refuges for marine life belong to England, the United States, and France: New Caledonia alone accounts for a quarter of the world's isolated reefs...
Poorly protected biodiversity
This is a particularly heavy responsibility, given the state of degradation of marine biodiversity. Although there are marine protected areas all over the world, their effectiveness is partly called into question by the findings of the Pristine project. "These areas are useful, particularly in allowing small fauna to rebuild their populations. But they are insufficient. They do not adequately protect certain species, particularly large predators." The main problem is their proximity to human activity. Their size is also an issue: they are too small and do not cover the entire vital territory of threatened species.
Although efforts are now being made to create new protected areas, David Mouillot believes they remain wholly insufficient. This is particularly true given the tendency to create these areas as far away as possible from zones that could give rise to conflicts of interest with coastal users such as fishermen and tourists. "The public authorities are thus creating reserves in sites that do not really need protection,"summarizes the researcher.
Public authorities that are poorly informed and sometimes unaware of the value of a natural heritage that is irreplaceable. "As scientists, we have a role to play in providing information and raising awareness in order to bring about political change." This approach can prove effective: in New Caledonia, following the Pristine project, the Entrecasteaux reefs were classified as a protected area.
What solutions are there to preserve marine life?
Ask all the countries involved to invest more? "It's hard to ask developing countries to do more. How can you stop villages that depend on fishing from going out to sea? But industrialized countries need to put in place some serious protection measures in their own countries."
What types of protection? "Create 'No entry' zones where access is prohibited. Or even reverse the logic, by creating areas where fishing is permitted, and automatically making other areas sanctuaries. This experiment could prove successful on a regional scale, with New Caledonia or Corsica serving as examples. It would demonstrate that fishermen themselves will ultimately benefit from these measures, which are the only way to rebuild fish stocks."
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