| Summary: | 碩士 === 國立中山大學 === 海下科技暨應用海洋物理研究所 === 100 === Sea turtles are large migratory animal stay in the water most of their life time. In the east coast of Taiwan, there is a strong northward Kuroshio current. It is hypothesis that ocean current might play an important role to the migration tracks of sea turtles in the region. To test the hypothesis, two turtle tracks based on Argos records were analyzed. The first turtle moved from Lanyu in the NE direction to Ishigaki Island. The second one moved southward from Dong-Auo, along the east coast of Taiwan, to the southern tip of Taiwan, and then detoured westward across the Taiwan Strait, swum southward along coastal China to Leizhou Peninsula finally. In this study, we analyze data of EASNFS model, drifter tracks, weather buoy records and MODIS sea surface temperature, to explore the relationship between the ocean currents and the migration tracks of sea turtles.
The Lanyu turtle seems follow very well with Kuroshio current in the early stage of its migration. The migration matches well with many Argos drifter tracks, and Lagragian drifter of EASNFS model. The probability of this turtle arriving Ishigaki Island is 26% if without other help. There is a turning point, as indicated by the comparison of model and real track. The Lanyu turtle swam hard to correct the migration route in order to reach the final destination.
The Dong-Auo turtle track is analyzed together with data of winds, waves and drifters. This turtle migrated southward along the east coast of Taiwan seemly agree with the northeast monsoon wind driven coastal current. The migration route turned west at the southern tip of Taiwan. The turn matches well with the currents indicate by Argos drifters, as well as EASNFS modeling. In additional to the guidance of currents, this migration route also followed the sea surface temperature of 21℃. In conclusion, this study suggests that turtles migration, in additional to the efforts of swimming and temperature guidance, will take advantage of prevailing currents to reach their final destinations.
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