This README_okuyama.txt file was generated on 2022-04-18 by Junichi Okuyama GENERAL INFORMATION 1. Title of Dataset: Latitudinal cline in the foraging dichotomy of loggerhead sea turtles reveals the importance of East China Sea for priority conservation 2. Author Information Corresponding Investigator Name: Junichi Okuyama (Ph.D.) Institution: Japan Fisheries Science and Education Agency E-mail: okuyamajunichi_at_gmail.com Co-investigator 1 Name: Akemi Watabe Institution: Ichinomiya Sea Turtle Association Co-investigator 2 Name: Shunichi Takuma Institution: Ichinomiya Sea Turtle Association Co-investigator 3 Name: Kentaro Tanaka (Ph.D.) Institution: Atmosphere and Ocean Research Institute, The University of Tokyo Co-investigator 4 Name: Kotaro Shirai (Ph.D.) Institution: Atmosphere and Ocean Research Institute, The University of Tokyo Co-investigator 5 Name: Naoko Murakami-Sugihara (Ph.D.) Institution: Atmosphere and Ocean Research Institute, The University of Tokyo Co-investigator 6 Name: Mamiko Arita Institution: Graduate school of Agriculture, Kindai University Co-investigator 7 Name: Kento Fujita Institution: Graduate School of Informatics, Kyoto University Co-investigator 8 Name: Hideaki Nishizawa (Ph.D.) Institution: Graduate School of Informatics, Kyoto University Co-investigator 9 Name: Tomoko Narazaki (Ph.D.) Institution: Atmosphere and Ocean Research Institute, The University of Tokyo Co-investigator 10 Name: Yoshiya Yamashita Institution: Okinoerabujima Sea Turtle Network Co-investigator 11 Name: Kazunari Kameda Institution: Kuroshima Research Institute, Sea Turtle Association of Japan 3. Date of data collection: 2015-2018 4. Geographic location of data collection: Isihigaki Island, Okinoerabu Island, and Ichinomiyha city, Japan 5. Funding sources that supported the collection of the data:JSPS KAKENHI, Award: 15H05584, Minoru Otsuka Foundation for Ocean and Environment, Award: FY2015 and Chiba Prefectural Environment Foundation, Award: FY2015 6. Recommended citation for this dataset: Okuyama, Junichi et al. (2022), Latitudinal cline in the foraging dichotomy of loggerhead sea turtles reveals the importance of East China Sea for priority conservation, Dryad, Dataset, https://doi.org/10.5061/dryad.gmsbcc2nj DATA & FILE OVERVIEW 1. Description of dataset These data were obtained to ivestigate the foraging destinations of loggerhead sea turtles nesting in Japan after their reproductive period. We directly tracked the post-nesting migration routes and the foraging destinations of 12 turtles using satellite transmitters. Moreover, we investigated their foraging destinations based on the isotope ratios of d13C and d15N of egg yolks that nesting turtles laid. Higher values of d13C and d15N of egg yolks indicate that turtles are neritic benthvores in East China Sea or the coastal area of Japan, while lower values indicates turtles are oceanic planktovores in the North Pacific Ocean. 2. File List: File 1 Name: Okuyama_Isotope analysis data of egg yolk.csv File 1 Description: Isotope analysis data of egg yolk of loggerhead turtles File 2 Name: Okuyama_et_al_Loggerhead_Tracking_data_deg.csv File 2 Description: Location data of satellite tracking on 12 loggerhead sea turtles METHODOLOGICAL INFORMATION Isotope data We obtained egg samples from a total of 82 loggerhead turtles nesting at three sites: Ishigaki Island, Okinoerabu Island and Ichinomiya, Japan. All whole egg samples were frozen at -20 C until analytical preparation. Following this, the egg yolk samples were dried at 60 C for 72?96 h. Lipids were removed using a chloroform-methanol (2:1) solution and then ground to a fine powder. The carbon and nitrogen stable isotope ratios in the egg yolks were measured. Isotope ratios in lipid-free powdered yolks (~2 mg) were determined at the Atmosphere and Ocean Research Institute, University of Tokyo, using a mass spectrometer (IsoPrime100, Elementar, Germany) interfaced with an elemental analyser (Vario Micro Cube, Elementar, Germany). The 13C and 15N were expressed as deviations from the standard (Vienna Pee Dee Belemnite and N2 in air for d13C and d15N, respectively), as defined by the following equation: d13C or d15N = (Rsample/Rstandard ?1) ~1000(), where R is 13C/12C or 15N/14N. The isotopic composition was calibrated against a commercial standard (L-Alanine AZ101-SS13, d13C = -19.6 and d15N = 13.7, Shoko Science, Japan). The analytical precision was estimated to be 0.2 for both d13C and d15N based on repeated analyses (n = 5) of in-house standard (mussel tissue standard for trace elements, SRM 2976, National Institute of Standards and Technology, USA) of which CN ratio is similar to egg yolk. Satellite tracking data Our location data of loggerhead turtles (Caretta caretta) nesting in Japan are given only at low horizontal resolution with decimal degree, because this species listed as an endangered species, and all published data in Dryad are made publicly available. If you want to use our location data with original resolution, please contact to corresponding author. To draw the migration trajectories, we used the location data with Argos location classes (B, A, 0, 1, 2, 3). The first two classes have no accuracy information assigned by Argos, and the remaining classes have reported accuracies of >1500, 500?1500, 250?500, and <250 m, respectively. However, accuracy has been measured on marine mammals at 10.3 and 6.2 km for class B and A and 4.2, 1.2, 1.0 and 0.49 km, respectively, for the remaining classes. Additionally, location data with excessive speed (>5 km h-1) were omitted. DATA-SPECIFIC INFORMATION FOR: Okuyama_Isotope analysis data of egg yolk.csv 1. Number of variables: 6 2. Number of cases/rows: 44 3. Variable List: Ishigaki_d15N (N2 AIR, per mil): d15N values of egg yolks that loggerhead turtles laied in Ishigaki Island Ishigaki_d13C (VPDB, per mil): d13C values of egg yolks that loggerhead turtles laied in Ishigaki Island Okinoerabu_d15N (N2 AIR, per mil): d15N values of egg yolks that loggerhead turtles laied in Okinoerabu Island Okinoerabu_d13C (VPDB, per mil): d13C values of egg yolks that loggerhead turtles laied in Okinoerabu Island Ichinomiya_d15N (N2 AIR, per mil): d15N values of egg yolks that loggerhead turtles laied in Ichinomiya city Ichinomiya_d13C (VPDB, per mil): d13C values of egg yolks that loggerhead turtles laied in Ichinomiya city 4. Missing data codes: None 5. Abbreviations used: VPDB: Vienna Pee Dee Belemnite DATA-SPECIFIC INFORMATION FOR: Okuyama_et_al_Loggerhead_Tracking_data_deg.csv 1. Number of variables: 4 2. Number of cases/rows: 18388 3. Variable List: LAT N (deg): North latitudinal locations of loggerhead turtles LON E (deg): East longitudinal locations of loggerhead turtles Type: Foraging type of loggerhead turtles tracked (Neritic benthivores vs. Oceanic planktovores which was determined by isotope analyses).ND represents that the foraging type was not determined because egg samples were not collected from those turtles ID: ID of turtles. For exapmples, O1 represents 1st turtle nesting on the Okinoerabu Island, whereas I2 represents 2nd turtle nesting on Ichinomiya city. 4. Missing data codes: None 5. Abbreviations used: ND: Not determined 6. Other relevant information: Our location data of loggerhead turtles (Caretta caretta) nesting in Japan are given only at low horizontal resolution with decimal degree, because this species listed as an endangered species, and all published data in Dryad are made publicly available. If you want to use our location data with original resolution, please contact to corresponding author.