Researchers have unveiled the mystery of the North Pacific sea turtle's long-term ocean journey.

According to foreign media reports, the mystery of the North Pacific turtle's ocean journey for several years is still little known. Using the data obtained by satellite tracking and other technologies, scientists have revealed a unique phenomenon, which may explain the path of this endangered species. The little-known journey of this turtle is called "lost years", which may last for twenty years or even longer. Now, a study led by Stanford University has clarified the secret of the epic migration between the birthplace of North Pacific turtles on Japanese beaches and their reappearance in feeding grounds on the coast of Baja California many years later.

The study, published in Frontier of Marine Science on April 8, provides evidence of intermittent channels of warm water, which enable turtles to cross the desolate and cold ocean barrier. These findings can help design conservation measures to protect turtles and other migratory marine life, because climate change is changing their actions.

Dana Briscoe, the lead author of the study, said: "For decades, our ability to connect the migration sites of this endangered species has remained elusive." During his research, he was a research assistant at Woods Environmental Institute of Stanford University, and now he works in Cawthron Institute, the largest independent marine science organization in New Zealand. "This work is based on a special study of these' lost years', and we are very happy to provide evidence of' hot corridors' for the first time in history to explain the long-term mystery of one of the greatest immigrants in the ocean."

Endangered "immigrants"

Wildlife explorers are excited to see turtles, but the dangers such as ship traffic and fishing nets are not so friendly. IUCN lists six of the seven species of sea turtles as extremely endangered, endangered or fragile. Although scientific progress has been made in the utilization of core habitats, researchers still know little about the movement of turtles and other long-lived marine life between different locations. This knowledge gap prevents us from effectively evaluating and protecting these species.

Researchers want to know how and why some turtles go to the west coast of North America, while others stay in the middle of the Pacific Ocean. Why some turtles-creatures that are highly sensitive to temperature-can cross a cold zone called the East Pacific Barrier between two marine areas, which usually stops most creatures.

In order to solve this mystery, the researchers created the largest satellite-marked turtle data set in history, and used complex remote sensing oceanography technology to collect the first batch of detailed records about turtle aging and stable isotope testing-a bone analysis that can be used to provide animal life information. This work depends on decades of research by an international team of scientists.

They first looked at a study in 15 years, which tracked the activities of more than 200 turtles with satellite tracking equipment. Six of the turtles caught the attention of researchers because, unlike their peers, they obviously moved to the North American coast. Stranger still, the researchers say that these "sentinels" travel in the early spring months. The study of remote sensing ocean conditions in this period shows that the water swam by the farthest "sentinels" is much warmer than that encountered by their companions during their travels.

A larger analysis includes measuring stable isotope "fingerprints" in the bones of turtles stranded on the beach to determine the year when the turtles arrived in Baja California. These stable isotopic characteristics can reveal when turtles migrated from the high seas to the coast. The analysis shows that in warm ocean conditions, the number of turtles moving eastward increases obviously every year.

The researchers believe that the possible reason is that the unusually warm sea surface temperature caused by El Ni? o phenomenon and other intermittent warming conditions has formed a "hot corridor", which enables turtles to cross the barrier of the eastern Pacific Ocean to reach the coastal feeding grounds.

The "corridor" appeared in late spring and early summer, and the temperature warmed up in advance a few months before its opening. This anomaly, especially if it lasts for several months, may provide key environmental clues for turtles and other animals concentrated in the eastern edge of the central Pacific Ocean, indicating that the "hot corridor" is opening. This hypothesis is supported by aerial survey, sea observation, grounding records and turtle tissue sample research.

A dangerous trend

This phenomenon may be part of a trend. As the earth has experienced unprecedented climate change, places that were once considered as insurmountable obstacles to species movement, such as the East Pacific barrier, are being redefined. This in turn changed the biological distribution and migration path from seabirds to white sharks, bringing new protection challenges.

For red sea turtles in the North Pacific, this trend may mean more accidental catches off the coast of Baja California and other potentially important North American feeding grounds, including the Gulf of Southern California. This study provides important insights, such as understanding the relationship between animal movement and climate change, which helps to predict when turtles and other protected species will be threatened.

The researchers warned that their multi-year data set only represents a snapshot of the important developmental period of turtles. The number of turtles entering the eastern North Pacific is very small, which limits the ability to comprehensively test the research hypothesis under different conditions. In order to do this, researchers call for more satellite markers and stable isotope research on turtle bones in this area.

Larry Claude, a senior author of the research report and a professor at Hopkins Ocean Station of Stanford University, said: "Understanding how and why species like the North Pacific red turtle move between habitats is very important to help them control threats. Emerging technologies and analysis can help clarify these journeys. "