The taxonomy of crime that takes place offshore is both diverse and acute. Nonetheless, illegal fishing is at the top of the food chain. It’s a $10 billion-a-year global business that’s thriving thanks to improved technology that allows fishing vessels to plunder the oceans more efficiently.

The Thunder thrived in this environment. Interpol had issued the ship a Purple Notice, the equivalent of adding it to a most wanted list, a designation given to only four other ships in the world up to that point. According to Interpol estimates, the vessel earned more than $76 million from illegal seafood sales in the previous decade than any other ship.

Although it had been prohibited from fishing in the Antarctic since 2006, the Thunder had been spotted there several times in the years since. That’s where the environmental organization Sea Shepherd discovered it in 2015. The captain of the Bob Barker, Peter Hammarstedt, warned through a translator that the Thunder was prohibited from fishing in those waters and would be stopped.

The Bob Barker and a companion ship, both operated by Sea Shepherd, trailed behind the trawler for 110 days and more than 10,000 nautical miles, with the three captains close enough to watch each other’s cigarette breaks and on-deck workout routines. The ships maneuvered through an obstacle course of giant ice floes, endured a cyclone-like storm, faced clashes between opposing crews, and nearly collided in what became the world’s longest pursuit of an illegal fishing vessel.

The chase ended with a distress call from the Thunder, according to the Outlaw Ocean Project, a nonprofit journalism organization whose reporter was on board the Bob Barker. “We’re sinking,” the Thunder’s captain pleaded over the radio. The ships operated by Sea Shepherd rescued the crew and tried gathering evidence of its crimes before the ship sank to the bottom of the ocean.

The Thunder’s senior crew members were arrested and taken to the nearest port officials in So Tomé and Prncipe. Three officers were charged with pollution, negligence, and forgery, among other things. However, the loss of the ship — and the evidence it carried, including the fish in the hold, onboard computers, various records, and fishing equipment — makes prosecution more difficult, according to Interpol and Sea Shepherd officials.

The second episode of “The Outlaw Ocean” podcast also focuses on another notorious case of illegal fishing that occurred off the coast of North Korea, in which battered wooden “ghost boats” drifted through the Sea of Japan for months, their only cargo the corpses of starved North Korean fishermen whose bodies had been reduced to powder.

For years, Japanese police were perplexed by the gruesome phenomenon, which they attributed to climate change, which drove the country’s desperate fishermen to dangerous distances from shore, where they became stranded and died from exposure.

However, an investigation based on satellite data by the Outlaw Ocean Project revealed what marine researchers now believe is a more likely explanation: China was sending a previously invisible armada of industrial boats to illegally fish in North Korean waters, violently displacing smaller North Korean boats and spearheading a 70% decline in once-abundant squid stocks.

The Chinese vessels — nearly 800 in 2019 — were present in defiance of United Nations sanctions prohibiting foreign fishing in North Korean waters. The sanctions, imposed in 2017 in response to North Korea’s nuclear tests, were meant to punish the country by preventing it from selling fishing rights in its waters in exchange for valuable foreign currency.

The incident exposes what experts call the largest known case of illegal fishing committed by a single industrial fleet operating in another country’s waters.