This study was co-authored by Brian Wong, a MGEL Research Associate alum

The authors of this study have revealed the largest known case of illegal fishing by a single fleet. Over 900 Chinese vessels were caught operating illegally in North Korean waters, and over 200,000 tons of fish were caught in illegal actions. A Global Fishing Watch led study focused on widespread illegal fishing that occurred in the waters between the Koreas, Japan, and Russia. This region is notorious for poor management, geopolitical conflict, and Japanese flying squid (Todarodes pacificus)— a sought after seafood. Due to this combination of factors, it has been the ideal spot for illicit activity, until now. The study combined four different existing satellite technologies: Automatic Identification System (AIS),  Satellite synthetic aperture radar (SAR), Visible Infrared Imaging Radiometer Suite (VIIRS), and high-resolution optical imagery to illuminate these “dark fleets”. It required international cooperation on a large scale from scientists in South Korea, Japan, Australia, and the U.S. that used machine learning developed by Global Fishing Watch, as well as technology from multiple organizations.

© Global Fishing Watch

The study focused on monitoring the activity of vessels in the claimed territory of the North Korean Exclusive Economic Zone (EEZ) in 2017 and 2018. Using their technologies they trained a neural network to identify pair trawlers, used satellite imagery to verify locations and size, and estimated at least 796 distinct pair trawlers operating in North Korean Waters in 2017 and 588 vessels in 2018. This also revealed that about 3,000 North Korean vessels fished in Russia’s EEZ in 2018. Only a small portion of the vessels were broadcasting their location through AIS, which highlights a bigger issue of the global seafood industry— illegal, unreported, and unregulated (IUU) fishing. In order to determine the identity of vessels operating illegally in these waters, the team use satellite imagery, visual observations, and Global Fishing Watch’s technologies. This large number of previously unmonitored vessels poses a substantial challenge for fisheries management.

Presence of satellite-detected vessels fishing in North Korean waters in 2018 © GFW

This study highlights political strife and maritime boundary disputes have prevented cooperation among these nations to join in regional fisheries management. Allowing shared vessel monitoring data, management plans, and stock assessments could help sustain fisheries in this region of the world. Moreover, improved fisheries governance would allow for more accountability from vessels caught conducting IUU fishing, and deter others from doing so. The presence of this dark fleet further highlights the depth of IUU fishing in the global seafood industry, but also represents a new era of satellite monitoring and international cooperation within fisheries management.

This study was conduced by Jaeyoon Park, Jungsam Lee, Katherine Seto, Timothy Hochberg, Brian A. Wong, Nathan A. Miller, Kenji Takaski, Hiroshi Kubota, Yoshioki Oozeki, Sejal Doshi, Maya Midzik, Quentin Hanich, Brian Sullivan, Paul Woods, and David A. Kroodsma.  


Jaeyoon Park, Jungsam Lee, Katherine Seto, Timothy Hochberg, Brian A. Wong, Nathan A. Miller, Kenji Takaski, Hiroshi Kubota, Yoshioki Oozeki, Sejal Doshi, Maya Midzik, Quentin Hanich, Brian Sullivan, Paul Woods, and David A. Kroodsma. “Illuminating Dark Fishing Fleets in North Korea.” Science Advances. 22 Jul 2020: Vol. 6, no. 30, eabb1197. DOI: 10.1126/sciadv.abb1197