A new dataset of intentional disabling of Automatic Identification System devices by fishing vessels provides insights into illegal, unreported, and unregulated fishing activity

Data from the shipboard Automatic Identification System (AIS), which was created as a collision avoidance tool, can provide information about global fishing activity, including illegal, unreported, and unregulated fishing. Fishing vessels may disable their AIS devices, but a new analysis identifies intentional disabling events in commercial fisheries and shows that, while some disabling events may be for legitimate reasons, others appear to be attempts to conceal illegal activities.

 

 

The new study, published November 2 in Science Advances, presents the first global dataset of AIS disabling in commercial fisheries, which obscures up to 6% of vessel activity.

First author Heather Welch, a project scientist in the Institute of Marine Sciences at UC Santa Cruz, worked on the study with researchers at Global Fishing Watch, which maintains an AIS dataset of vessel activity, and NOAA Fisheries. After Global Fishing Watch developed a way to distinguish intentional disabling from gaps in satellite coverage and other technical issues, Welch used a machine learning method to identify four primary reasons for AIS disabling.

“There are some legitimate reasons why vessels disabled their AIS, but we found two situations in which it is done for potentially nefarious reasons, either to fish in unauthorized locations or to obscure unauthorized transshipments,” she said. “This dataset is now operationalized, and the data are produced in real time, so it can be used to target inspections and improve fisheries management.”

5 million hours of fishing vessel activity intentionally obscured

For the study, the researchers identified over 55,000 suspected intentional disabling events between 2017 and 2019, obscuring nearly 5 million hours of fishing vessel activity. More than 40% of the total hours obscured by suspected AIS disabling occurred across four hotspots, three of which are areas of concern for illegal fishing: the Northwest Pacific and areas adjacent to the Exclusive Economic Zones (EEZs) of Argentina and West African nations. These areas contain rich fishing grounds with limited management oversight.

Disabling events were concentrated in waters adjacent to EEZ boundaries, suggesting that vessels may be disabling AIS before entering unauthorized locations to fish illegally. In many cases, vessels go dark as they approach the edge of an EEZ where they are not authorized to fish, Welch said. “For example, you might see a Korean-flagged vessel heading toward Argentina, and then it goes dark in international waters just outside of Argentina’s EEZ,” she said.

Disabling common in areas such as the Falkland Islands

Notably, disabling was particularly common within and adjacent to EEZs with overlapping claims, such as the Falkland/Malvinas Islands that are disputed by the U.K. and Argentina. The political conflicts in these regions may create blind spots for enforcement.

The study also found evidence that some disabling is done for legitimate reasons by vessels engaged in legal activities. In some cases, Welch said, AIS disabling may be done to hide the locations of good fishing grounds from competitors. The fourth disabling hotspot was caused by U.S. trawlers disabling in U.S. waters off the coast of Alaska. “This is one of the most intensely managed fishing grounds in the world, and these events likely constitute location hiding from competitors,” she said.

The other legitimate reason for disabling AIS is for protection from piracy. “Using a database of historical attacks, we can see that vessels switch off AIS in these historically dangerous waters, and that may be so that pirates aren’t able to track and intercept them,” Welch said.

This is an extract from the University of California and the full piece can be found here. The full journal paper published in Science Advances can be read here.

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