Satellites reveal 75% of world's industrial fishing vessels are 'hidden'

two large fishing boats at sea
Fishing boats off the coast of Angola. (Image credit: Getty Images)

Earth-observing satellites have helped detect previously unmapped global fishing vessels, revealing nearly 75% of the world's industrial activity at sea was "hidden" from public view. 

Using satellite imagery from 2017-2021, vessel GPS data and machine learning software, a team led by the Global Fishing Watch created the first world map of large vessel traffic and offshore infrastructure. Their findings bring to light a large number of "dark vessels," or those that previously didn't appear in public monitoring systems, offering a better understanding of the global impact of human activity at sea

The new maps, which have been made public, offer a more complete view of ocean industrialization, which can help researchers tackle global concerns such as climate change. Having a more comprehensive view of vessel traffic will improve estimates of greenhouse gas emissions at sea and hold the parties responsible for marine pollution accountable. 

"By seeing and characterizing the activity of these expansive dark fleets, we can begin to better understand and quantify not just illegal fishing but a great deal of human activity that is impacting our marine environment," Paul Woods, chief innovation officer of Global Fishing Watch, said in a statement from the organization. "These are exciting times when it comes to open, accessible data that anyone can use for free to understand and advocate for the fragile marine areas they care about most."

Related: Satellites uncover widespread illegal fishing in Pacific Ocean

The team's analysis showed that 75 percent of the world's industrial fishing vessels and more than 25 percent of transport and energy vessels are not publicly tracked, which presents challenges for managing natural resources such as protected marine areas, according to the study.

Most of the unmapped industrial fishing vessels were found around Africa and south Asia. While there are a number of legitimate reasons why a vessel might not appear in a public monitoring system, many of the unmapped vessels are often engaged in illegal, unreported and unregulated fishing, according to the statement. 

Satellite imagery and machine learning were used to create the first global map of vessel traffic and offshore infrastructure, revealing previously unmapped industrial use of the ocean.  (Image credit: © 2023 Global Fishing Watch)

"A new industrial revolution has been emerging in our seas undetected — until now," David Kroodsma, director of research and innovation at Global Fishing Watch and co-lead author of the study, said in another statement announcing the findings. "On land, we have detailed maps of almost every road and building on the planet. In contrast, growth in our ocean has been largely hidden from public view. This study helps eliminate the blind spots and shed light on the breadth and intensity of human activity at sea." 

The team was able to identify the location of vessels and offshore infrastructure in coastal waters across six continents where more than 75% of industrial activity is concentrated. This, in turn, revealed changing trends in fishing activity, which dropped globally by about 12 percent during the COVID-19 pandemic. 

Meanwhile, offshore energy development, such as oil drilling and wind turbines, increased significantly, but transport and energy vessel activity remained stable. 

"Historically, vessel activity has been poorly documented, limiting our understanding of how the world's largest public resource — the ocean — is being used," Fernando Paolo, co-lead author and senior machine learning engineer at Global Fishing Watch, said in the second statement. "By combining space technology with state-of-the-art machine learning, we mapped undisclosed industrial activity at sea on a scale never done before."

Their findings were published Jan 3 in the journal Nature.  

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Samantha Mathewson
Contributing Writer

Samantha Mathewson joined as an intern in the summer of 2016. She received a B.A. in Journalism and Environmental Science at the University of New Haven, in Connecticut. Previously, her work has been published in Nature World News. When not writing or reading about science, Samantha enjoys traveling to new places and taking photos! You can follow her on Twitter @Sam_Ashley13. 

  • Questioner
    Are they saying people are cheating lying scallywags?
    I am shocked i tell you!
    Next they will be suggesting that unregulated capitalism is a bad thing.
  • waltAG
    So many undocumented vessels seems like a great opportunity for pirates!
  • Questioner
    Pirates, dictators, shell corporations and gangsters are unregulated capitalists.
  • Unclear Engineer
    There are a lot of reasons that ships are not tracked.

    In the particular cases of fishing vessels, even if they are registered and fishing legally in designated waters, they are still in competition with other legal vessels doing the same thing. So, if they think that they have specific knowledge of a "hot spot" to make a big catch, they are usually interested in getting there and doing their fishing without anybody else knowing where they are catching so many fish. Turning off their AIS is just "normal" behavior.

    Add to that the rich who don't want to be tracked, the ships dodging all the "sanctions" imposed on various international trades, naval vessels that don't want to be tracked by "the other guys" and the actual pirates, it is no wonder that 75% of the ship traffic is not on the tracking channels.

    So, I think this satellite visual tracking capability is a good way to get a handle on not only how much of some activities are occurring, but also who is doing them. It might sound like "Big Brother in the Sky", but it is also like "The Wild West" on the water at this point.
  • Phil35
    Read this white paper, there is technology to see vessels with AIS off ! look at the website of this compagny: regards
  • Unclear Engineer
    RF location works when RF is being used. But, the Japanese have already demonstrated that you can avoid using RF at sea even with large numbers of large ships, way back in 1941.

    So, "situational awareness" needs lots of diverse capabilities to be robust.

    And, considering that NASA has now demonstrated laser communication over long distances, it may become even harder to detect signals between vessels, satellites, etc. as the laser technology gets into commercial uses.

    Which brings up the point about detecting extraterrestrials: if they have advanced to using pinpoint-to-pinpoint communication with lasers, would we have any way of knowing they were nearby? Maybe SETI is looking for technology that would be "ancient" to any species that has the technology to get to us from where they originated.