Dark fleets: Hidden industrial fishing activity exposed

A new study led by Global Fishing Watch has utilized artificial intelligence and satellite imagery to uncover the previously hidden scale of human activity at sea, revealing that around 75% of the world’s industrial fishing vessels are not publicly tracked. 

The study offers an unprecedented global map of large vessel traffic and offshore infrastructure, highlighting the extent of “dark” activities previously invisible to public monitoring systems.

Study significance

David Kroodsma, the director of research and innovation at Global Fishing Watch and co-lead author of the study, emphasized the significance of this research in understanding the new industrial revolution occurring in our oceans. 

“A new industrial revolution has been emerging in our seas undetected – until now,” said Kroodsma. “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.” 

How the research was conducted

The research team, which included experts from the University of Wisconsin-Madison, Duke University, UC Santa Barbara, and SkyTruth, analyzed a vast dataset of satellite imagery spanning from 2017 to 2021. This effort covered coastal waters across six continents, where over three-quarters of industrial activity is concentrated. 

By combining GPS data with radar and optical imagery over five years, the researchers identified vessels that did not broadcast their positions. Machine learning algorithms were then employed to determine which of these vessels were likely engaged in fishing activity.

Poorly documented activity

Fernando Paolo, a senior machine learning engineer at Global Fishing Watch and co-lead author of the study, highlighted the historical challenge of documenting vessel activity. 

“Historically, vessel activity has been poorly documented, limiting our understanding of how the world’s largest public resource – the ocean – is being used,” said Paolo. “By combining space technology with state-of-the-art machine learning, we mapped undisclosed industrial activity at sea on a scale never done before.”

Dark fleets

The study revealed numerous “dark fleets,” vessels not visible on public monitoring systems, within many marine protected areas. It also showed a significant number of vessels in countries’ waters that were previously thought to have little-to-no vessel activity. 

Study co-author Professor Jennifer Raynor from the University of Wisconsin-Madison noted a discrepancy in publicly available data regarding fishing activities in Asia and Europe. Their mapping uncovered that Asia has a substantially higher number of fishing vessels compared to Europe.

“Publicly available data wrongly suggests that Asia and Europe have similar amounts of fishing within their borders, but our mapping reveals that Asia dominates – for every 10 fishing vessels we found on the water, seven were in Asia while only one was in Europe,” said Raynor. “By revealing dark vessels, we have created the most comprehensive public picture of global industrial fishing available.”

Offshore energy development 

The study also observed changes in human ocean activity, particularly during the COVID-19 pandemic. While fishing activity dropped globally, transport and energy vessel activities remained stable. 

Notably, offshore energy development surged during the study period, with oil structures increasing by 16% and wind turbines more than doubling, outnumbering oil platforms by 2021. China’s offshore wind energy saw the most dramatic growth.

Broader implications 

Patrick Halpin, a professor at Duke University and co-author of the study, underscored the broader implications of these findings. 

“The footprint of the Anthropocene is no longer limited to terra firma,” said Professor Halpin. “Having a more complete view of ocean industrialization allows us to see new growth in offshore wind, aquaculture and mining that is rapidly being added to established industrial fishing, shipping and oil and gas activities.” 

“Our work reveals that the global ocean is a busy, crowded and complex industrial workspace of the growing blue economy.” 

The researchers believe that this technology has the potential to address climate change challenges. Accurate mapping of all vessel traffic can enhance greenhouse gas emission estimates at sea, while mapping infrastructure can inform wind development and track marine degradation due to oil exploration. 

A new era in ocean management 

Study co-author Christian Thomas, a geospatial engineer at SkyTruth, stressed the importance of identifying offshore infrastructure.

“Identifying offshore infrastructure is critical for understanding offshore energy development impacts and trends, and is crucial data for our work to detect marine pollution events and hold responsible parties to account,” said Thomas.  

The study not only illuminates previously unseen aspects of ocean industrialization but also democratizes access to satellite monitoring technology. 

“Previously, this type of satellite monitoring was only available to those who could pay for it. Now it is freely available to all nations,” said Kroodsma. “This study marks the beginning of a new era in ocean management and transparency.”

The study is published in the journal Nature. 

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