"Day after day after day, when I came on deck I saw objects floating by: toothbrushes, bottlecaps and soap bottles," says Captain Charles Moore.
The trash he found floating, like a Japanese traffic cone, was from much of the world.
Beneath the surface, a jellyfish was so entangled in a scrap of synthetic net that its tentacles had grown around the plastic strands.
The trash was found in a patch of ocean called the North Pacific Gyre where the currents can trap floating debris for years.
"I have no doubt that some of these things that we're discovering out there have been there since the dawn of the plastic era in the 1950's," says Moore.
As plastic ages it crumbles, leaving so many tiny fragments that Moore found seawater in the Gyre contained more plastic than plankton, the tiny sea life that many ocean creatures feed on.
To jellyfish, the plastic particles seem like food.
"It's like putting them on a plastic diet," says Moore. "It becomes part of their tissue."
In his lab, Moore studies jellyfish embedded with plastic.
"I saw that it had brightly colored plastic fragments inside," he says. "Pieces like this blue monofilament fishing line."
That Moore found lots of plastic in sea trash does not surprise Rob Krebs, of the American Plastics Council.
"Just because it's everywhere, it shouldn't be the whipping boy of environmentalists," says Krebs.
Krebs says plastic is ever more widely used because it does so much, so well.
"It's a good material, and so when we talk about Charles Moore we really have to look in the mirror," says Krebs. "We need to look at ourselves."
Put another way: Plastic doesn't pollute, people pollute.
"It's everyone's fault," says Moore. "There are no guiltless parties here."
After a heavy rain in Los Angeles, the plastic flows into the Pacific in torrents.
Even with efforts to clean it up, some will escape, eventually reaching the synthetic sea of the North Pacific Gyre.