Hatchery release has been used for the conservation of green turtles for many years. To improve the rescue management of released individuals and avoid their negative impact on wild populations, the application of individual markers is particularly important. Quick response (QR) code was used to tag the individual of released turtles in Huidong Sea Turtle National Nature Reserve, the unique spawning site and nature reserve for sea turtles in China. The viscosity differences of four safe and non-toxic glues (e.g., epoxy resin, acrylic glue, ABS glue, and nail gel 401) in different age groups were tested. The results revealed that epoxy resin glue has the best adhesion effect on 8-year-old turtles, and the intact rate after 50 days was 100%. It is suitable to be used for the rescue of stranded turtles within 50 days of release. Nail gel 401 has the best adhesion effect on the carapace of 1-year-old turtles, with an intact rate of 100% after 50 days, which can be used for short-time conservation of young turtles. The release experiments of 18 eight-year-old sea turtles with passive integrated transponder (PIT) tags, QR codes, and steel tags showed that QR codes are conducive to public participation and improve rescue efficiency. In fact, QR code is a powerful measure to overcome the limitations of the existing individual label. However, the QR code fused with turtle carapace can only be applied for turtle rescue and tracing in the short-term due to its limited persistence.

The insights gained from individual tracking can improve the conservation of released young green sea turtles by providing detailed data on migration route, feeding place and habitat distribution. During the fishing moratorium from May 1 to August 16 in 2021, we used satellites to track 6 juvenile green sea turtles released from China’s Huidong Sea Turtle Nature Reserve, and located and reconstructed their migration routes and foraging sea areas. The tracking data shows that the longest tracking time is 91 days, the shortest time is 10 days, and the total tracking time is 213 days, of which three (50%) obtained tracking data for more than one month, and the total movement distances (statistics LC3-LCB) ranges from 124 to 4627 km, while the accurate movement distances (counted by dot pitch above LC0) ranged from 39.5-2331 km. The average daily movement distances ranges from 3.95 to 51.4 km, and the average speed varies between 0.16 to 2.14 km/h. The green turtles released from the China Turtle Bay migrate along the northern coastline of the South China Sea or go straight to the South China Sea. After a month or so, they migrate from Huidong Turtle Bay to Hainan Lingao, Beibu Gulf and Xisha Islands. The northern coast of the South China Sea is one of the migration routes of green sea turtles. Beibu Bay, Zhanjiang Port, Daya Bay, Red Bay, Nan’ao Island, Zhelin Bay and Xisha Islands are important foraging places for green sea turtles. The protection of migration routes and important foraging grounds is one of the key measures to protect sea turtles.