East Pacific Sea Turtle Tracking Project (1996-1997)

The oceanic movements of a captive-raised adult loggerhead turtle
(Caretta caretta) were monitored with satellite telemetry for 368 days from 10
August 1996 to 12 August 1997. During this time the turtle migrated across the
Pacific Ocean, covering more than 11,500 km between Santa Rosaliita, Baja
California, Mexico (28 40N, 114 14W), and Sendai Bay, Japan (37 54N, 140 56E).
The average speed during migration was 1.3 km/h and the maximum recorded speed
was 1.84 km/h. These findings are consistent with the hypothesis that
loggerheads feeding in the eastern Pacific eventually return to nest on western
Pacific beaches. Baja California loggerhead turtles have been shown, through
molecular genetic analysis (Bowen et al. 1995) and flipper tag returns (Uchida
and Teruya 1988, Resendiz et al. 1998), to be primarily of Japanese origin. We
conclude that loggerhead turtles are capable of transpacific migrations and
propose that the band of water between 25 and 30 degrees North latitude, the
Subtropical Frontal Zone, may be an important transpacific migratory corridor.
Recent findings (Polovina et al. 2000) indicate that juvenile loggerheads in
the North Pacific move westward against weak (0.1-0.3 km/hr) eastward
geostrophic currents, demonstrating that passive drift may not entirely explain
the dispersal of loggerheads.