30 per cent by 2030? Study maps out how to protect the world’s oceans

As governments work towards an international pledge to protect at least 10 per cent of the world’s oceans by 2020, scientists are proposing an even wider movement to save more than one-third of the marine ecosystem.

Scientists have mapped out an enormous network of potential protected areas, covering more than one-third of the world’s oceans, to conserve marine biodiversity threatened by overfishing, emerging deep-sea mining, plastic contamination, and climate change.

They released a report outlining the network on April 4, a day before the conclusion of the second round of negotiations at the United Nations toward a landmark treaty to address the ongoing decline of marine biodiversity on the high seas.

Report co-author Alex Rogers, a marine biologist at the University of Oxford, said the study puts forward the first detailed plan for a planet-wide network of marine sanctuaries.

The sanctuaries would dot the globe from pole to pole, represent all marine ecosystem categories, and provide migration corridors for sea life. They would be fully protected from all human exploitation, including industrial fishing and deep-sea mining, according to the report.

“This can be seen as one of a number of measures that we must take to stop the degradation of the ocean,” Rogers told Mongabay. While the sanctuary network by no means offers an exhaustive solution, he said, “it will provide a good basis to protect and conserve the astounding diversity of marine life.”

Rogers has seen firsthand the harmful effects of human activity on the otherworldly ecosystems beneath the ocean’s surface during more than 25 years exploring the deep sea and coral reefs. On expeditions to a chain of largely unexplored vents in the southwestern Indian Ocean, Rogers was struck to find the underwater mountains littered with fishing gear and ghost nets floating through the water, entangling wildlife long after they are abandoned.

“We were saddened to see the dead and dying animals trapped by those nets,” Rogers said. “It was shocking how much abandoned fishing gear [has] already gotten to these marvelous deep-sea ecosystems.”

To design the network, the researchers used a computer program to divide the high seas into nearly 25,000 squares, each 10,000 square kilometres (3,860 square miles) in area. In allocating areas for protection, the program took into account data such as the distributions of sharks, whales, seamounts, trenches and hydrothermal vents, as well as commercial fishing operations and mining claims.

We were saddened to see the dead and dying animals trapped by those nets. It was shocking how much abandoned fishing gear [has] already gotten to these marvelous deep-sea ecosystems.

Alex Rogers, marine biologist, University of Oxford

It also built in resilience to wider environmental changes and uncertainty. For example, it looked at sea-surface temperature data to identify places likely to change relatively slowly or adapt readily under rising temperature stress.

In the end, aiming to protect at least 30 per cent of each kind of marine habitat, the network covered between 35 and 40 per cent of the high seas. “While the designs demonstrate the practicality of creating networks based on existing information, they are not specific proposals for protection,” the report states. The report, titled “30×30: A Blueprint For Ocean Protection,” resulted from a year-long collaboration between academics at the University of York, University of Oxford and other institutions in the UK and the NGO Greenpeace.

The high seas represent about two-thirds of the world’s oceans, but they lie outside national boundaries and are not governed by any country or international body. As such, these areas lack a comprehensive oversight structure to protect the marine life that relies on them.

The UN’s high seas treaty would create a system for coordinating the conservation and sustainable use of marine biodiversity in the high seas. It could include a mechanism for establishing various kinds of protected areas, and if so, the network outlined in the new report “shows how that could then be implemented,” Rogers said.

“I believe it is critical if we are to avoid the continuing decline of the ocean and its species leading towards a 6th global extinction event,” he added.

Governments around the world are already working toward a pledge under the Convention on Biological Diversity to protect at least 10 per cent of coastal and marine areas by 2020. But a move has been afoot recently among some scientists, conservationists and governments to up the ante and get countries to commit to protecting 30 per cent of the ocean by 2030. (The UN reports that as of 2017 just 5.3 per cent of the ocean has been protected, including 13.2 per cent of waters within national jurisdictions and just 0.25 per cent of the high seas.)

Aside from protecting biodiversity, creating a global network of protected areas is in all countries’ interests, according to the study authors: underwater ecosystems play an important role in mitigating climate change, with fish and squid in the sea helping to regulate carbon in the atmosphere. The animals feed on the phytoplankton that draws carbon out of the atmosphere and process it into solid feces that sink to the bottom of the sea, where the carbon remains.

In January 2018, Mongabay investigated the efficacy of marine protected areas by reviewing 42 scientific studies and talking to seven experts. The investigation found that, overall, ocean sanctuaries do appear to help fish stocks and other marine species to recover within their boundaries.

While the main driver for creating protected areas is to ensure the conservation of marine biodiversity, protected areas only shelter marine species from certain regulated human activities. They don’t directly address acidification, plastic pollution, agricultural waste, and illegal fishing.

Even so, a network of marine sanctuaries would offer protection from the cumulative effects of human activities, said Arlo Hemphill, an ocean campaigner with Greenpeace USA. “Climate change is already having a huge impact on the oceans and the fish, whales and all life that lives within the sea,” Hemphill said. “By creating these protected spaces where fishing and deep seabed mining [are] not permitted, you give the ocean a chance to adapt and recover from the other stressors like plastics and climate change that we’re also trying to get a handle on.”

However, not all scientists think marine protected areas are the way to go. Ray Hilborn, a marine biologist and fisheries scientist at the University of Washington, US, criticised the initiative to set aside 30 per cent of the oceans in sanctuaries.

“For the high seas, almost all fish caught there are quite migratory (tunas, billfish, sharks and some fish like jack mackerel),” Hilborn wrote in an email. “There is no evidence that closing 30 per cent of the area would affect the catch. It would simply cause the boats to make their catches elsewhere.”

“There are substantial costs to trying to enforce closed areas, and forcing boats to move elsewhere would likely result in more fuel use, longer catch times and the cost of fishing would go up as a result,” he said.

Hilborn told Mongabay he did support closing sensitive bottom habitats, such as deepwater corals, to bottom trawling, a destructive method of fishing, but surface or midwater fishing did not need to be banned.

This story was published with permission from Mongabay.com.

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