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Long-term monitoring of black turtles Chelonia mydas at coastal foraging areas off the Baja California Peninsula

2009; Inter-Research; Volume: 11; Linguagem: Inglês

10.3354/esr00264

1863-5407

Melania C. López‐Castro, Volker Koch, A Mariscal-Loza, WJ Nichols,

Avian ecology and behavior

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 11:35-45 (2010) - DOI: https://doi.org/10.3354/esr00264 Long-term monitoring of black turtles Chelonia mydas at coastal foraging areas off the Baja California Peninsula Melania C. López-Castro1,2, Volker Koch3,4,*, Antonio Mariscal-Loza3, Wallace J. Nichols5,6 1Grupo Tortuguero de Las Californias, C.P. 23060 La Paz, Baja California Sur, Mexico 2Centro de Investigaciones Biológicas del Noroeste, C.P. 23090 La Paz, Baja California Sur, Mexico 3Departamento de Biología Marina, Universidad Autónoma de Baja California Sur, C.P. 23080 La Paz, Baja California Sur, Mexico 4Investigación para la Conservación y el Desarrollo A.C. (INCODE A.C.), La Paz, Baja California Sur, Mexico 5The Ocean Conservancy, Davenport, California 95017, USA 6Department of Herpetology, California Academy of Sciences, San Francisco, California 94118, USA *Corresponding author. Email: vokoch@uabcs.mx ABSTRACT: Monthly in-water monitoring was conducted at 5 foraging areas off the Baja California Peninsula, Mexico, from 2001 to 2006 to assess black turtle population status. Turtles were captured with entanglement nets, size (straight carapace length, SCL) and weight of each individual were recorded and turtles were tagged on both rear flippers. A total of 1238 turtles were captured, involving 6309 h of effort. Of this total, 937 ind. were marked and 155 were recaptured. SCL ranged from 30 to 95.5 cm; immature turtles accounted for >94% of the total catch and were dominant at all sites. However, size class distribution varied among sites, and turtles from the Gulf of California were significantly larger than those caught in the Pacific. Catch per unit of effort (defined as the number of turtles caught per 100 m of net soaking for 24 h) varied from 1.79 at Bahía Magdalena to 17.35 at Punta Abreojos. Mean (±SD) annual growth rate for black turtles was 2.27 ± 0.71 cm yr–1, with the lowest and highest growth rates in Bahía Magdalena (1.37 ± 0.71 cm yr–1) and Laguna Ojo de Liebre (3.05 ± 2.23 cm yr–1), respectively. Lack of recaptures from adjacent sites and multiple recaptures of specimens at the site of origin over several years indicate a low connectivity among foraging areas and a high site fidelity. Hence, strengthening local protection is imperative to the recovery of black sea turtle populations. KEY WORDS: Black turtle · East Pacific green turtle · Chelonia mydas · Population ecology · Northwest Mexico · Growth · Size distribution · CPUE · Population status Full text in pdf format PreviousNextCite this article as: López-Castro MC, Koch V, Mariscal-Loza A, Nichols WJ (2010) Long-term monitoring of black turtles Chelonia mydas at coastal foraging areas off the Baja California Peninsula. Endang Species Res 11:35-45. https://doi.org/10.3354/esr00264 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 11, No. 1. Online publication date: March 10, 2010 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2010 Inter-Research.