Off-radar fishing threatens efforts to preserve stocks, study warns

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Widespread untracked fishing is hindering global efforts to protect depleted fish stocks and marine environments, according to a study that maps undisclosed activities at sea for the first time.

About 75 per cent of the world’s industrial fishing vessels are not publicly tracked, according to research by conservation organisation Global Fishing Watch (GFW), threatening food security, livelihoods and marine ecosystems.

While the footprint of land-based extractive industries such as agriculture is plotted almost down to the last square metre, oceans were “still the wild west”, said David Kroodsma, one of the study’s lead authors and GFW’s director of research and innovation.

This discrepancy leaves governments and organisations operating in the dark, hindering efforts to achieve a global commitment made at the 2022 COP15 biodiversity summit to protect at least 30 per cent of land and sea by 2030, he said.

GFW’s study, published in the journal Nature on Wednesday, used GPS positions from hundreds of thousands of ocean-going vessels as well as satellite radar imagery and artificial intelligence to track activity in the sea between 2017 and 2021.

It found that on average 63,000 vessels were detected at any given time. About half were industrial fishing vessels, three-quarters of which were off-radar, including many around Africa and south Asia.

Of the remainder, including container ships and fuel tankers as well as passenger and supply vessels, a quarter were untracked.

Kroodsma said some of these so-called ghost ships lacked automatic identification system (AIS) transponders, which broadcast their location and identity to coastal authorities and other vessels. Others turned off the devices, often because they were engaged in illicit activities such as unregulated or illegal fishing or forced labour, he added.

As much as 20 per cent of fishing was potentially unregulated or conducted illegally, he estimated, “but the truth is, we don’t actually know because the data is so poor”.

The study also found that the global distribution of industrial fishing differs from the generally understood pattern.

According to AIS data, Europe and Asia have similar levels of activity in terms of fishing hours. But with non-broadcasting ships factored in, Asia accounted for 70 per cent of global fishing activity, compared with 12 per cent for Europe.

North America and Africa’s total tracked and untracked fishing was 7 per cent of the global total each, while in South America and Australia it was 4 and 2 per cent respectively.

Another key finding was that untracked fishing vessels routinely entered marine protected areas, with an average of five operating in the Galápagos Marine Reserve and 20 in the Great Barrier Reef each week. 

To protect such areas and safeguard fish stocks, governments should mandate that all vessels are publicly trackable, according to campaign group Oceana. “If you’re fishing on the ocean, you’re fishing on a public resource and you should be required to prove that you are doing so legally,” said chief executive Andrew Sharpless. 

According to UN Food and Agriculture Organization estimates, a third of the world’s fish stocks are overexploited, meaning fish are being caught faster than they can reproduce. Critical marine habitats are also being depleted, with between 30 and 50 per cent lost due to human activity.

Fishing activity decreased globally by 12 per cent during the Covid-19 pandemic and has not yet fully recovered, but previous overfishing meant many stocks were nonetheless at their limit, according to GFW. “We are already catching all the fish we can possibly catch,” said Kroodsma.

Overfishing represents a risk not only for marine ecosystems but also for the 500mn people around the world who rely on the fishing sector for their livelihoods, he warned. Fish stocks are also crucial for global food security.

The oceans face further pressure as other industrial activities in the sea increase, according to the study. The number of container ships, fuel tankers and offshore energy installations rose during the research period, with offshore wind turbines surpassing oil platforms for the first time, excluding infrastructure in Venezuela’s Lake Maracaibo.

GFW predicts that as demand for renewable energy grows, the seas will see more development. This could create conflict over space, which would need to be managed, Kroodsma said. 

“The bigger picture here is that the ocean economy is growing faster than the global economy,” he said, adding that the study would help prevent this happening “entirely unmapped”.

Cartography by Steven Bernard