Mexican feds have just seized $750,000 of fish guts worth their weight in cocaine. The swimming bladders from totoaba bass — fish on the verge of extinction in the country’s tiny Gulf of California — are a hot commodity in China, where they are believed to be the secret to youthful skin and easing aching joints. A single dried yellow-brown bladder, carved out of totoaba bass illegally caught by poachers, can fetch up to $100,000 in Shanghai and Hong Kong, where they’ve long been a mainstay of traditional medicine.

The bladders are thought to contain high levels of collagen, a protein known to give skin its strength and structure. Traditionally, the dried organs are cooked into soups and stews and eaten in hopes that it will restore youthfulness and elasticity to skin and strengthen joints. In some cases, the “fish maws” are also believed to make the aches and pains of pregnancy more tolerable. The practice is thought to be centuries old, and bigger bladders have historically fetched higher prices. Bladders from totoaba bass, which can grow up to 2 meters long, are especially valuable.

Cooked into soup, illegal 'fish maw' is thought to release beauty-restoring, joint-relieving collagen.

As with many traditional remedies, the science is spotty. The fish bladders certainly do contain collagen — in particular, a specialized form known as isinglass, which has been been used to dress wounds since the 18th century. Collagen, which gets its name from the French word coller — to glue — is tough stuff, appearing to provide an external framework for new tissue to grow on when applied to wounds. There’s been a lot of recent scientific interest in using fish-derived collagen for medical purposes because it seems to be better at resisting infection than animal collagen. Still, there isn’t much scientific evidence to show that eating the collagen in fish bladder broth is an effective way to get it into your system, at least not in a useful way.

As one Mexican fisherman told CNN, “If it really worked for beauty, I should be beautiful by now. Instead, look at me.”

Still, scientific proof rarely trumps cultural convictions, and sales of the contraband fish bladders are thought to fuel an international black market now thought to be worth billions of dollars. PROFEPA, the Mexican counterpart to the U.S. Environmental Protection Agency, has actively attempted to crack down on illegal trafficking by flying over the totoaba’s federally protected spawning grounds twice daily to search for poachers and inspecting all vehicles leaving the sanctuary. Striking a deal with local fishermen to protect the endangered species — they’ve been on the list since commercial fishing ravaged populations in the 1970s — the Mexican government has offered locals $3,100 a month not to fish in the area, but the payout, which is reportedly closer to $2,000 a month, doesn’t even come close to the potential payout for even a single bladder.

Despite federal efforts to curb the fish market trade, PROFEPA still pulls up nine totoaba-catching nets a day. So far, it’s unclear whether existing Mexican drug cartels have fostered the link to illegal Chinese importers.

Photos via https://www.flickr.com/photos/azchael/