This is also a big deal for commercial and environmental reasons.

Eels are extremely popular as food. China has aquafarms to grow them, but the problem is getting ahold of young eel to grow, because we can't get them to breed in captivity. They catch wild ones, then raise them in farms. At first, the Japanese eel got clobbered.

Then what had been happening is that people would catch young wild European eels ("elvers") then export them illegally to be raised in Chinese aquafarms:

Moreover, the effort is increasingly urgent due to the dramatic decline in European eel populations since the 1980s, marked by a staggering drop of over 95% in the number of glass eels arriving at European coasts. The species is now highly endangered, facing multiple threats that complicate conservation efforts.

https://www.europol.europa.eu/media-press/newsroom/news/law-enforcement-casts-net-over-256-eel-smugglers

Law enforcement casts net over 256 eel smugglers

Europol-led operation finds 25 tonnes of trafficked eels worth EUR 13 million destined for Asia

Then after European eels got depleted, baby eel smuggling started happening in North America.

https://apnews.com/article/business-europe-china-smuggling-nyc-state-wire-baab790064d148b72dc5b1752fab7d39

Baby eels are among the most lucrative fish species in the seafood world. The U.S. fishery for American eels is based almost entirely in Maine. The baby eels are often worth more than $2,000 per pound at the docks.

https://vifreepress.com/2024/03/boaters-caught-trying-to-smuggle-over-110000-live-eels-out-of-puerto-rico-feds-say/

SAN JUAN — Two people are facing charges after the United States Coast Guard found them trying to take over 110,000 eels out of Puerto Rico without proper paperwork, prosecutors said.

U.S. Customs and Border Protection officials noticed a “suspicious” boat about 40 miles off the northern coast of Puerto Rico on the morning of February 21, the U.S. Attorney’s Office for the District of Puerto Rico said in a March 1 news release.

The boat was described as “flagless and outfitted for smuggling.” The U.S. Coast Guard approached the boat and, when it refused to stop, had to “neutralize” it, prosecutors said.

Once onboard, officials found two people with 22 bags of live American eels, prosecutors said. Each bag held “over 5,000 eels”, officials said, totaling at least 110,000 eels.

https://en.wikipedia.org/wiki/Freshwater_eel_poaching_and_smuggling

Freshwater eel poaching and smuggling have emerged in recent years as a direct response to the sustained popularity of eels as food combined with the eels' low population, endangered status, and subsequent protections. Freshwater eel are elongated fish in the Anguillidae family of ray-finned fish. The three most commonly consumed eel species are the Japanese eel (A. japonica), European eel (A. anguilla), and American eel ( A. rostrata).

The life cycle for eels has not been closed in captivity on a sustainable level, and any eel farms rely entirely on wild-caught elvers (juvenile eels). These elvers are caught from their native ranges in North America and Europe and are smuggled into East Asian eel farms, where they are often relabeled as the native Japanese eel to subvert legislation. The eels are smuggled disguised as other cargo, such as luggage[1] or other meat products.[2]

If we could figure out how to get eels to breed in captivity, which we currently don't know how to do, it could resolve the eel shortage. That probably involves a better understanding of their sexual habits.