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  • Writer's pictureTravis Turgeon

How Missing AIS Data from Dark Ships Can Help Mitigate Illegal Fishing

"Dark shipping is a plague on legal and sustainable wild fisheries and threatens everything from the livelihoods of those who depend on them to the consumers who buy the seafood."

Automatic Identification Systems, or AIS, have been used for quite some time to track the movements of commercial ships at sea. The systems deliver data to end-users, often relayed through earth observation (EO) satellites operated by companies providing space services, that contains valuable information on a ship’s location, heading, speed, and more. AIS data helps maritime authorities identify suspicious behavior or pinpoint illicit activities at sea, spanning everything from Sanctions Avoidance to Human Trafficking to Illegal (IUU) Fishing.

Still, AIS systems have some significant limitations that make it hard for authorities to mitigate the issues in real-time. Not only can AIS systems be manually switched off at any given moment, but the operational data can also be manipulated so that a ship appears to be operating differently than it is or be in places it is not. AIS data manipulation is known as “Spoofing,” while ships operating without their Automatic Identification Systems turned on are referred to as “Dark Ships” or “Ghost Ships.”

The limitations of AIS often result in end users trying to filter through diluted information, and bad actors that are savvy and capable of some of the more advanced manipulation techniques can buy themselves enough time to carry out their illegal or illicit operations and continue on their voyage before authorities can intervene.

However, some maritime authorities are now taking a different approach to monitoring ships with AIS data, and with a fine-tuned strategy, these approaches could shed light in more meaningful and applicable ways.

Below, we outline how the absence of one ship’s AIS data helped authorities uncover an illegal fishing operation - shedding light on how others can use the same strategies globally to mitigate the occurrences of IUU Fishing and help bring some relief to the world’s at-risk wild fisheries.

The Situation: The Oyang 77

In January 2019, a South Korean fishing boat - the Oyang 77 - departed from a port in Montevideo, Uruguay, heading for the productive wild fisheries off the coast of Argentina. As the Oyang 77 entered Argentinian waters on January 10th, the ship’s AIS signal was promptly lost, appearing to have turned off its AIS transponder.

Over the next two weeks (17 days, to be exact), the vessel disabled its AIS transponder eight more times, leaving gaps in its voyage history and leaving its actual location at those times unknown. On February 7th, the Oyang 77 reappeared consistently on AIS, heading towards Comodoro Rivadavia, Argentina.

The kicker?

The ship was being escorted to the coast by the Argentinian Coast Guard and would be quickly arrested for illegal fishing in Argentinian waters upon its arrival.

About the Oyang 77

The Oyang 77 is a South Korean-flagged fishing vessel that belonged (at the time) to a fishing fleet run by the Sajo Oyang corporation - which has been well-known for its illicit activities at sea, which have been reported on by The Guardian at least once before.

The Oyang 77 was seized in New Zealand for illegally dumping fish into the ocean, falsifying reports on their catch loads, and not paying workers according to local law. This incident was reported on by Oceana - a global non-profit focusing on ocean conservation and fisheries management.

Digging Deeper into the Incident Involving the Oyang 77

It’s a common practice for fishing boats looking to hide their illegal fishing activity. Once they arrive near the Exclusive Economic Zone (EEZ) of a country’s territorial waters, they simply shut off their AIS transponders and head towards protected or off-limits fishing zones. This usually happens within about 200 nautical miles of an EEZ before they enter the protected waters.

This was precisely the case with the Oyang 77 in January 2019. It vanished on AIS near the EEZ of Argentina and reappeared at least once on AIS near the location just outside the zone during the AIS outages.

The Argentinian Coast Guard discovered the fishing vessel inside their EEZ with its nets deployed in the water. When they boarded the Oyang 77, they found over 300,000 lbs of seafood, most of which was assumed to come from within the EEZ.

After the discovery, the Argentinian Coast Guard deployed a helicopter, airplane, and at least one vessel to escort the trawler back to shore. The Oyang 77 was released after issuing a fine of 25 million Argentinian Pesos (around $550,000), and all of the fishing equipment onboard was confiscated.

While this situation did not use any particular strategy for monitoring ships with AIS data, it sheds light on how it can be used to mitigate illegal fishing in the future (covered below).

A New Approach to Uncovering Illegal Fishing with Space-Based AIS Data

Traditional ship monitoring with AIS data has proven time and time again to be a challenging task - primarily due to the untimely nature of how AIS data is observed and delivered. The team at Global Fishing Watch recognized this and is now taking a new approach to the data that could help minimize the legwork involved and reduce the time needed to take action against vessels suspected of operating illicitly.

Alongside a team of data scientists and machine learning experts, Global Fishing Watch recently started looking at AIS data outages rather than tracked positions to more quickly and accurately locate ill-intentioned incidents.

The team analyzed over 28 billion AIS signals from 2017 to 2019 and found more than 55 thousand gaps in transmissions over the period. These gaps are estimated to hide around 6% of commercial fishing activity around the globe - a massively significant number considering the state of the world’s oceans.

While the data described above was not used to apprehend the Oyang 77 in Argentina, the US Coast Guard and the Canadian Department of Fisheries and Oceans are already using the data to pinpoint the most valuable vessels to pursue.

The data could also prove valuable to authorities in charge of vessel inspections on fishing boats by analyzing the AIS tracks of ships after they arrive at a port. By inspecting a ship's AIS tracks and locating the vessels with recurring or long-lasting AIS outages, authorities can narrow the pool of suspicions by a large margin - allowing them to make better use of time, money, and resources.

Still, not all AIS outages indicate illegal or illicit activity. Some vessels periodically switch off their AIS systems for legitimate reasons, including shutting off AIS in areas with a high risk of pirating or during maintenance periods.

To separate legitimate incidences of AIS outages from those that are suspicious, the research team headed by Global Fishing Watch uses machine learning (ML) technologies to identify which is which.

For example, if a ship is found motionless while not operating its AIS transponder, it may or may not indicate suspicious behavior. So what the ML technology does is analyze the time and variability of the AIS outage, along with the recent AIS history of the vessel, and flag the system as suspicious when conditions are met.

While these instances do not always indicate something illegal, stationary fishing vessels often use the tactic to illegally offload their catch, so if the location data and vessel history match up, they are flagged as suspicious.

How Dark Shipping Puts Sustainable Fisheries and Fish Stocks at Risk

Dark shipping is a plague on legal and sustainable wild fisheries and threatens everything from the livelihoods of those who depend on them to the consumers who buy the seafood.

Below, we outline some of the most significant risks that dark shipping imposes on the commercial fishing industry, solidifying why mitigating dark shipping fleets and illegal fishing occurrences is important.

90% of Global Fish Stocks are Fully Exploited or Overfished

More than a third of global wild fisheries are now considered unsustainable, threatening the livelihoods of over 3 billion people who depend on the fisheries for a source of protein and income.

Fish Farms Cannot Support the Global Demand for Seafood

Seafood is one of the world’s last sources of animal protein that can be harvested in mass quantities. While seafood farming has dramatically increased in recent decades, over 100 million tons of wild seafood is captured yearly for sale in the global food market. To put things into perspective, IUU fishing accounts for nearly 20% of that total - solidifying the need for better regulations and mitigation of dark ships operating in the fishing industry.

While legally-operating commercial fish farms can reduce the opportunities for illegal fishing operations, more is needed to satisfy the global demand - making it imperative to better regulate and manage these risks.

From Illegal Fishing Operations to Your Dinner Table

Much of the world is now conscious of where they source their food, but when the seafood on the shelves of your local grocery store is unknowingly coming from illegal fishing operations, it makes it hard to make an impact on the individual level.

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