ESR 28:1-10 (2015)  -  DOI: https://doi.org/10.3354/esr00671

Summer-restricted migration of green turtles Chelonia mydas to a temperate habitat of the northwest Pacific Ocean

Takuya Fukuoka1,*, Tomoko Narazaki2, Katsufumi Sato1

1Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
2Sea Mammal Research Unit, School of Biology, University of St Andrews, Fife KY16 8LB, UK
*Corresponding author:

ABSTRACT: The foraging habitats of green turtles Chelonia mydas range from tropical to temperate areas. Previous studies have generally been biased toward tropical and sub-tropical areas; hence, available data do not accurately describe the species’ foraging activity in temperate areas. To reveal seasonal patterns of habitat use in temperate areas, we conducted a by-catch survey, a mark-recapture study, and satellite tracking of green turtles along the Sanriku Coast, a temperate zone in the northwest Pacific Ocean. From July through November of 2005 to 2014, 78 green turtles were captured during a period of relatively high water temperatures (16 to 24°C). Straight carapace length (SCL) ranged from 36.8 to 85.6 cm (average: 49.4 ± 11.4 cm; n = 78), indicating that most of the turtles were juveniles. In the mark-recapture study, 14 of 72 tagged turtles were recaptured 5 to 426 d after release, 12 of which were recaptured south of the release point. Based on satellite tracking data, 3 turtles travelled more than 500 km to reach southern habitats, where water temperature was warmer (13 to 25°C) than along the Sanriku Coast (4 to 22°C). Our results revealed that the Sanriku Coast is a seasonally restricted habitat for juvenile green turtles, which migrate to southern habitats in winter, and that turtles in temperate areas migrated longer than those in tropical and sub-tropical areas. This is the first report of seasonal migration of juvenile green turtles to a temperate habitat in the northern Pacific Ocean. 


KEY WORDS: By-catch · Mark-recapture · Satellite tracking · Temperate habitat · Juvenile turtles


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Cite this article as: Fukuoka T, Narazaki T, Sato K (2015) Summer-restricted migration of green turtles Chelonia mydas to a temperate habitat of the northwest Pacific Ocean. Endang Species Res 28:1-10. https://doi.org/10.3354/esr00671

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