When they stop to fish for them, the Vietnamese crews hold rubber hoses in their mouths attached to an onboard air compressor. They strap lead weights around their waists to help them dive, often dangerously deeper than a hundred feet, to collect the cucumbers, which can fetch over $300 per pound in China. During an arrest in 2016, Baiei said, one of these divers shot to the surface too quickly, causing excruciating bubbles to form in his joints, getting what is called the bends.

