Degrees of residence of Guiana dolphins (Sotalia guianensis) in Ilha Grande Bay, south-eastern Brazil: a preliminary assessment

Over half of the Guiana dolphins (Sotalia guianensis) studied in Ilha Grande Bay, Brazil, exhibited low or no residency, indicating a fluid population structure. Using photo-identification of dorsal fins from 17,969 photographs, researchers cataloged 462 distinct individuals, with an average resight interval of 35 ± 27.4 days. The findings suggest potential links between dolphin presence and local resource availability, such as prey or protected areas. This preliminary assessment highlights the dynamic nature of this coastal dolphin population in southeastern Brazil.

Espécie, M. d. A., Tardin, R. H. O., & Simão, S. M. (2010). Degrees of residence of Guiana dolphins (Sotalia guianensis) in Ilha Grande Bay, south-eastern Brazil: a preliminary assessment. Journal of the Marine Biological Association of the United Kingdom, 90(8), 1633–1639. https://doi.org/10.1017/s0025315410001256