All seven species of sea turtle are in trouble because of human impacts, especially the one favored for its beautiful "tortoiseshell" carapace, the Hawksbill. One way to help, as with ivory, rhino horn, bear bile, and tiger claw, is to make certain you NEVER buy the real thing.
From the brochure...
HAWKSBILL SEA TURTLES, Eretmochelys imbricata (CRITICALLY ENDANGERED) are found world- wide. They spend most of their time in the open ocean before returning to the beach where they were hatched to lay their own eggs. Like many egg-laying reptiles, warmer sand temperatures in the next produce female hatchlings, cooler ones produce males. Like all seven species of sea turtle, the Hawksbill is in trouble because of harvesting their eggs and meat for food and their shells for carvings and jewelry, and because of by-catch.
Hawksbill sea turtle graphic (banner) by Christina Ward