Bottlenose dolphin Tursiops truncatus at São Tomé Island (São Tomé and Príncipe) — relative abundance, site fidelity and social structure

  • A Pereira
  • F Martinho
  • C Brito
  • I Carvalho

Abstract

Although the bottlenose dolphin Tursiops truncatus is one of the most common cetacean species around São Tomé Island, Gulf of Guinea, little research has focused on this species in this region. This study investigated the population of bottlenose dolphins around São Tomé Island by estimating the minimum population size, site fidelity and social structure. During a total of 226 surveys between 2002 and 2006, and in 2012, 51 sightings were recorded but only 33 had photographic data suitable for rigorous analysis. The minimum annual total population size, based on permanently marked dolphins, was 37 individuals, and the discovery curve indicated that a large part of the population remained undiscovered. The annual sighting rate for 76 highly distinctive adult animals ranged from 0.20 (seen in one year only) to 1.0 (seen every year of the study period). Resighted individuals demonstrated low association values; the dolphins seemed to form a single group with a fluid structure.

Keywords: Africa, conservation, group composition, Gulf of Guinea, photo-identification, population size, social association, South Atlantic

African Journal of Marine Science 2013, 35(4): 501–510

Author Biographies

A Pereira
Escola de Mar, Edifício ICAT – Campus da FCUL, Campo Grande 1749-016 Lisboa, Portugal
F Martinho
Escola de Mar, Edifício ICAT – Campus da FCUL, Campo Grande 1749-016 Lisboa, Portugal
C Brito
Escola de Mar, Edifício ICAT – Campus da FCUL, Campo Grande 1749-016 Lisboa, Portugal; Centro de História de Além-Mar, Faculdade de Ciências Sociais e Humanas, Universidade Nova de Lisboa, Avenida de Berna, 26 C, 1069-061 Lisboa, Portugal
I Carvalho
Escola de Mar, Edifício ICAT – Campus da FCUL, Campo Grande 1749-016 Lisboa, Portugal; Associação Para as Ciências do Mar, Edifício ICAT – Campus da FCUL, Campo Grande 1749-016 Lisboa, Portugal
Published
2013-12-19
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X