East Pacific Sea Turtle Tracking Project (1996-1997)
Entry ID:
seamap105
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Summary
Abstract:
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.
Purpose:
Juvenile loggerhead turtles, Caretta caretta, in the 20 - 85 cm straight carapace length (SCL) size range have been observed in the offshore waters along the Pacific coast of California, USA, and the Baja California peninsula, Mexico (Pitman 1990, Nichols, in press). Bartlett (1989) suggested that these turtles might be of western Pacific origin, migrating 10,000 km and feeding on pelagic red ... crabs (Pleuroncodes planipes) along the Baja California coast. Subsequently, Pacific loggerheads appear to utilize the entire North Pacific during the course of development in a manner similar to Atlantic loggerheads' use of the Atlantic Ocean (Bolten et al. 1998). After a period of more than 10 years (Zug et al. 1995), mature turtles evidently cross the Pacific Ocean from pelagic waters and foraging areas along the Baja California coast to return to natal beaches, a journey of more than 12,000 km in each direction. This is the first effort to document pelagic movements of North Pacific loggerheads from feeding grounds to nesting areas using satellite telemetry. Previous telemetry studies of loggerhead turtles have documented post-reproductive movements (Stoneburner 1982), pelagic movements (Polovina et al. 2000), home ranges (Renaud and Carpenter 1994), navigational abilities (Papi et al. 1997) and homing behavior (Luschi 1996). However, few studies of sea turtles have documented pre-nesting movements from feeding grounds to breeding areas. Notably, Renaud and Landry (1996) documented movement of a Kemp's ridley turtle (Lepidochelys kempii) from feeding grounds in Louisiana, USA, to its successful nesting in Rancho Nuevo, Mexico. A unique opportunity to track the movements of an adult-sized loggerhead turtle, rarely encountered along the Baja California coast, emerged in 1996. The turtle had been raised in captivity and used in the initial genetic analysis of Baja California loggerhead turtles (Bowen et al., 1995). Its mature size (Kamezaki and Matsui, 1997), genetic affinities with Japanese turtles, and the existence of a previous tag return from Japanese waters of a captive-raised, Baja California loggerhead turtle (Resendiz et al., 1998) were the deciding factors in choosing this particular turtle for the study. The objective of the study was to monitor the oceanic movement, using satellite telemetry, of a Pacific loggerhead turtle initially captured on feeding grounds along the Baja California coast. Movement data also were examined with respect to oceanographic and meteorological information in an effort to gain insight into the navigational cues that guide adult sea turtles and to identify possible transpacific movement corridors. The results are from a single telemetered turtle (loggerhead series 07667) that was captive-raised for ten years and released from the coast of Baja California, Mexico. SUPPLEMENTAL INFORMATION: A captive-raised adult loggerhead turtle (series number 07667) was monitored following release at Santa Rosalita, Baja California, Mexico (28 40N, 114 14W). The turtle was first captured in October 1986 by sport fishermen in Baha de Los Angeles, Baja California, and maintained in captivity at the Centro Regional de Investigaciones Pesqueras, Sea Turtle Research Station (CRIP-STRS). At the time of capture, it had a straight carapace length (SCL) of 29.9 cm and weighed 4 kg. The turtle was used in a study of captive growth rates and in genetic analysis of Pacific loggerhead stocks. Genetic studies suggested that this individual was of Japanese origin (Bowen et al. 1995). At the time of release, the turtle measured 83.4 cm (SCL) and weighed 95 kg. The tail measured 3.5 cm from the edge of the carapace to the tip. A model ST-3 backpack transmitter manufactured by Telonics, Inc. (Mesa, AZ, U.S.A.) was programmed with a duty cycle of 6 hours on, 6 hours off. The transmitter was attached to the second vertebral scute (counting from the anterior) of the turtle's carapace using a modified version of the attachment technique described by Balazs et al. (1995). Specifically, we substituted a thin layer (<1 cm) of tinted two-part marine epoxy (Marine-Tex; Montgomeryville, PA, USA) for Silicone Elastomer. Epoxy was also used to create a small faring on the leading and trailing edges of the transmitter to reduce drag (Watson and Granger 1998). Release of the telemetered turtle occurred about 2 km offshore of Santa Rosalita, Baja California, Mexico (28 40N, 114 14W), on 10 August 1996, 10 years after initial capture. Transmission data were received via the Argos/NOAA satellite-based location and data collection system, which interprets and classifies signal locations in categories called location classes (LC). In addition to the date and location, data included surface time for each 12-hour period, average dive time for each 12-hour period, last dive time and temperature. Only positions with LCs of 0,1, 2 or 3 were included in the analysis of distances traveled and swim speeds. LCs of 1 or greater have known error factors of > 1,000 m and accuracy increases with location class (LC = 2, accuracy within 350 m; LC = 3, within 150 m). Distances and headings were calculated using variations of the Great Circle Equation (Dunlap and Shufeldt 1969). Each segment of the track, or distance traveled between quality locations, is presented and swim speeds for these segments are calculated by dividing the distance traveled by the time between locations. The straightness index, or the ratio between the great circle distance (shortest line between the release location and the final location) and the calculated distance traveled, was calculated using endpoints of the track. http://search.csmonitor.com/durable/1997/11/18/home/home.1.html http://www.nationalgeographic.com/ngkids/9911/turtle/protectors.html http://edition.cnn.com/NATURE/9907/19/turtles.enn/ http://www.turtles.org/adelita http://www.oxygengroup.com/specialprojects/adelita.html http://www.oxygengroup.com/specialprojects/japanstorysp.html (Spanish) http://www.adelitasjourney.com/ CURRENTNESS REFERENCE: ground condition SPATIAL REFERENCE INFORMATION - GEODETIC MODEL Horizontal Datum Name: D_WGS_1984 Ellipsoid Name: WGS_1984 Semi-major Axis: 6378137.000000 Denominator of Flattening Ratio: 298.257224
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Description:
Access data from the OBIS and OBIS-SEAMAP websites.
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Geographic Coverage
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Spatial coordinates
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N: 39.84
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S: 21.57
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E: -114.24
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W: 140.92
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Temporal Coverage
Start Date:
1985-12-03
Stop Date:
1986-03-14
Use Constraints
PICCCBY
Personnel
Role:
INVESTIGATOR
Role:
TECHNICAL CONTACT
Phone:
+81-42-512-0742
Email:
iida at nipr.ac.jp
City:
Tachikawa-shi
Province or State:
Tokyo
Postal Code:
190-8518
Country:
JAPAN
Role:
DIF AUTHOR
City:
Tachikawa-shi
Province or State:
Tokyo
Postal Code:
190-8518
Country:
Japan
Publications/References
Mitsuo Fukuchi et al. Chlorophyll a Concentration measured continuously with Surface Water Monitoring System during the JARE-27 Cruise to Syowa Station, Antarctica in 1985/86. JARE Data Rep., No.142(Marine Biology 13), 1-151
Creation and Review Dates
Last DIF Revision Date:
2012-04-09
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