Oceanic adults, coastal juveniles: tracking the habitat use of whale sharks off the Pacific coast of Mexico

PeerJ

article

Dení Ramírez-Macías¹  Nuno Queiroz²  Simon J. Pierce⁴  Nicolas E. Humphries³  David W. Sims³  Juerg M. Brunnschweiler⁷ 

[1] Tiburón Ballena México;Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, CIBIO/InBIO—Universidade do Porto;The Laboratory;Marine Megafauna Foundation;Ocean and Earth Science, National Oceanography Centre Southampton, Waterfront Campus, University of Southampton;Center for Biological Sciences, Highfield Campus, University of Southampton;Independent Researcher

关键词: Movements;    Habitat use;    Diving behavior;    Size segregation;    Whale sharks;    Pacific coast of Mexico;    Habitat conservation;   

DOI  :  10.7717/peerj.3271

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Eight whale sharks tagged with pop-up satellite archival tags off the Gulf of California, Mexico, were tracked for periods of 14–134 days. Five of these sharks were adults, with four females visually assessed to be pregnant. At least for the periods they were tracked, juveniles remained in the Gulf of California while adults moved offshore into the eastern Pacific Ocean. We propose that parturition occurs in these offshore waters. Excluding two juveniles that remained in the shallow tagging area for the duration of tracking, all sharks spent 65 ± 20.7% (SD) of their time near the surface, even over deep water, often in association with frontal zones characterized by cool-water upwelling. While these six sharks all made dives into the meso- or bathypelagic zones, with two sharks reaching the maximum depth recordable by the tags (1285.8 m), time spent at these depths represented a small proportion of the overall tracks. Most deep dives (72.7%) took place during the day, particularly during the early morning and late afternoon. Pronounced habitat differences by ontogenetic stage suggest that adult whale sharks are less likely to frequent coastal waters after the onset of maturity.

【 授权许可】

CC BY