In Brazil, the whale shark occurs in coastal waters from Ceará to Rio Grande do Sul States and at oceanic islands, like the archipelagos of Fernando de Noronha, São Pedro and São Paulo and Trindade. Information gathered from these phenomena, for instance, has been valuable to assess the seasonality of occurrence, aspects of population structure and dynamics of whale sharks in coastal waters of Australia the Gulf of Mexico the Gulf of California Belize the Seychelles and the Maldives. Sites with predicted seasonal foraging aggregations of whale sharks offer the best opportunity to study the species on a regular basis. Commonly, environments with an optimal scenario for whale shark occurrence provide suitable conditions for primary and secondary productivity, as the main known purpose for whale shark aggregation is foraging. Past studies on the ecology and biology of whale sharks have suggested a relationship between their movements and environmental features, including sea surface temperature, chlorophyll a concentrations, bottom relief and ocean currents. The whale shark Rhincodon typus (Smith 1828) is a pelagic and highly migratory filter-feeding species distributed around the globe in tropical and subtropical waters. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. The CNPq also provided the PhD scholarship grant (#140567/2012-7) for BCLM. The Grupo Fundação Boticário de Proteção à Natureza ( provided grant (#0760_20072 FHVH) for equipment. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: All relevant data are within the paper and its Supporting Information file.įunding: The Secretaria da Comissão Interministerial para os Recursos do Mar (SECIRM/Brazilian Navy and Brazilian Council for Scientific and Technological Development (CNPq provided grant (#405460/2012-0 FHVH) for logistics and equipment through Pró-Arquipélago/Oceanic Islands Program. Received: Accepted: SeptemPublished: October 26, 2016Ĭopyright: © 2016 Macena, Hazin. Schmidt, University of Illinois at Chicago, UNITED STATES Irrespective of its use for feeding or reproduction, this insular habitat serves as a meeting point for both juvenile and adult whale sharks, and may play an important ecological role for the species.Ĭitation: Macena BCL, Hazin FHV (2016) Whale Shark ( Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean. swollen abdomen and bite marks on the pectoral fins), and the potential mating behaviour exhibited by one male, suggest that the ASPSP area might also have a role in whale shark reproduction. At the same time, evidence of reproductive activity in adult females ( i. During this period, the ocean current weakens and the waters are enriched by eggs and larvae of fishes and invertebrates that attract marine life to forage. The majority of sightings occurred between February and June. The maturational stages were classified by size as immature (9.0 m 46.51%) with almost half of the observed animals being mature specimens. The estimated mean ± SD size was 8.27 ± 2.52 m (range: 2.5–14.0 m) with no significant differences in size across the year. Forty-nine whale sharks were recorded from February 2005 to May 2014. In the present work, we assessed the ecological and behavioural aspects of the whale sharks that visit the archipelago of São Pedro and São Paulo (ASPSP), located ~1,000 km off the coast of Brazil in the equatorial Atlantic Ocean. Despite an increase in the number of whale shark studies, information on mating and parturition grounds is still lacking. Conversely, aggregations of mature adults are rarely observed, and their occurrence is correlated with oceanic environments. Feeding aggregations occur mainly in nearshore areas and are composed primarily of immature individuals. Consequently, foraging is believed to be the main reason for the formation of whale shark aggregations. ![]() Whale sharks are generally associated with environmental factors that drive their movements to specific locations where food availability is high.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |