15 Mar North Pacific Loggerhead Research
North Pacific loggerhead turtles were recently studied to see if the immature loggerheads in the Sea of Japan follow the prevailing current to the south or north, or if they are unable to leave the area when it gets cold. The study followed 30 immature captive-reared turtles tagged with Wildlife Computers SPOT tags released in the summer of 2011.
All 30 turtles were released at the same time. Seventeen of the tagged turtles were tracked for an average of 232 days and for a distance of over 5,000 km. Seven of those reached the North Pacific Ocean after being tracked for an average of 413 days and over 9,000 km. Several of the turtles never left the Sea of Japan but were tracked for an average of 70 days.
The tags allowed researchers to follow some of the turtles for over a year. Most of the turtles moved directly to an important nursery ground. The turtles were tracked along courses similar to the migrations of wild loggerheads that depend on the Tsushima Warm Current and its extensions.
They discovered some differences between a couple of the groups of turtles, especially between the large and smaller turtles. Researchers gained valuable insight into how water temperature and ocean currents affect migration patterns and movement habitats of immature loggerheads.