Population size estimates of pink river dolphins (Inia geoffrensis) using mark-recapture methods on photo-identification
Keywords:Pink River dolphin, Inia, population size, photo-identification, mark-recapture, Amazon and Orinoco river basins
Population size estimates of pink river dolphins (Inia geoffrensis) are critical to assess the conservation status of this species and the impacts of increasing human stressors in freshwater ecosystems. Photo-identifications of Inia dolphins were collected between February 2007 and August 2009 in two locations of the Colombian Amazon and Orinoco river basins. Population sizes of Inia were obtained by using the closed (Petersen) mark-recapture model on photo-identifications. The total population size estimate for right/left side individuals was 129/71 Inia dolphins (CV=0.36/0.35) in the Amazon location and 125/58 Inia dolphins (CV=0.77/0.69) in the Orinoco location. The survey and analysis protocols were designed to try to meet mark-recapture assumptions. However, photo-identification was incomplete in both study areas, and there could be recruitment and unequal probabilities of capture due to preferences of individuals for certain areas. Further effort should be focused towards expanding the photo-identification catalogues and creating long-term monitoring programs.
Barlow, J. and Reeves, R. R. (2009) Population status and trends. Pages 918–920 in Perrin, W. F., Würsig, B., Thewissen, J. G. M. (Eds). Encyclopedia of Marine Mammals. Second Edition. Academic Press, San Diego, CA, USA.
Best, R. C. and da Silva, V. M. F. (1993) Inia geoffrensis. Mammalian Species 426: 1-8.
Connor, R. C., Wells, R. S., Mann, J. and Read, A. J. (2000) The bottlenose dolphin: Social relationships in a fission-fusion society. Pages 91–126 in Mann, J., Connor, R. C., Tyack, P. L. and Whitehead, H. (Eds). Cetacean Societies: Field Studies of Dolphins and Whales. University of Chicago Press, Chicago, IL, USA.
Gomez-Salazar, C., Trujillo, F. and Whitehead, H. (2011) Photo-Identification: A reliable and noninvasive tool for studying pink river dolphins (Inia geoffrensis). Aquatic Mammals 37: 472-485. http://dx.doi.org/10.1578/AM.37.4.2011.472
Gomez-Salazar, C., Trujillo, F., Portocarrero-Aya, M. and Whitehead, H. (2012a) Population, density estimates, and conservation of river dolphins (Inia and Sotalia) in the Amazon and Orinoco river basins. Marine Mammal Science. 28(1): 124-153. http://dx.doi.org/10.1111/j.1748-7692.2011.00468.x
Gomez-Salazar, C., Trujillo, F. and Whitehead, H. (2012b) Ecological factors influencing group sizes of river dolphins (Inia geoffrensis and Sotalia fluviatilis). Marine Mammal Science. 28 (2): E124-E142. http://dx.doi.org/10.1111/j.1748-7692.2011.00496.x
Gomez-Salazar, C., Coll, M. and Whitehead, H. (2012c) River dolphins as indicators of ecosystem degradation in large tropical rivers. Ecological Indicators. 23: n19-26. http://dx.doi.org/10.1016/j.ecolind.2012.02.034
Gowans, S., Whitehead, H., Arch, J. and Hooker, S. (2000) Population size and residency patterns of northern bottlenose whales (Hyperoodon ampullatus) using the Gully, Nova Scotia. Journal of Cetacean Research and Management 2: 201-210.
Hammond, P. S., Mizroch, S. A. and Donovan, G. P. (1990) Individual recognition of cetaceans: use of photo-identification and other techniques to estimate population parameters. Report of the International Whaling Commission. Special Issue 12: 3-17.
Hammond, P. S. (2009) Mark-Recapture. Pages 705-709 in Perrin, W., Würsig, B. and Thewissen, J. G. M. (Eds). Encyclopedia of Marine Mammals. Elsevier Academic Press, Canada.
Hammond, P. S. (2010) Estimating the abundance of marine mammals. Pages 42-67 in Boyd, I., Bowen, W. D. and Iverson, S. J. (Eds). Marine Mammal Ecology and Conservation. Oxford University press, New York.
Loch, C., Marmontel, M. and Simões-Lopes, P. C. (2009) Conflicts with fisheries and intentional killing of freshwater dolphins (Cetacea: Odontoceti) in the Western Brazilian Amazon. Biodiversity and Conservation 18: 3979-3988. http://dx.doi.org/10.1007/s10531-009-9693-4
Mann, J., Connor, R. C., Tyack, P. and Whitehead, H. (2000) Cetacean Societies: Field Studies of Dolphins and Whales. University of Chicago Press, Chicago, USA.
Martin, A. R. and da Silva, V. M. F. (2004) River dolphins and flooded forest: seasonal habitat use and sexual segregation of botos (Inia geoffrensis) in an extreme cetacean environment. Journal of Zoology 263: 295-305. http://dx.doi.org/10.1017/S095283690400528X
Martin, A. R., da Silva, V. M. F. and Salmon, D. (2004) Riverine habitat preferences of botos (Inia geoffrensis) and tucuxis (Sotalia fluviatilis) in the central Amazon. Marine Mammal Science 20: 189-200. http://dx.doi.org/10.1111/j.1748-7692.2004.tb01150.x
McGuire, T. L. and Henningsen, T. (2007) Movement patterns and site fidelity of river dolphins (Inia geoffrensis and Sotalia fluviatilis) in the Peruvian Amazon as determined by photo-identification. Aquatic Mammals 33: 359-367. http://dx.doi.org/10.1578/AM.33.3.2007.359
Read, A. J., Urian, K. W., Wilson, B. and Waples, D. M. (2003) Abundance of bottlenose dolphins in the bays, sounds, and estuaries of North Carolina. Marine Mammal Science 19: 59-73. http://dx.doi.org/10.1111/j.1748-7692.2003.tb01092.x
Reeves, R. R., Jefferson, T. A., Karczmarski, L., Laidre, K., O’Corry-Crowe, G., Rojas-Bracho, L., Secchi E. R., Slooten, E., Smith, B., Wang J. Y. and Zhou, K. (2008). Inia geoffrensis. IUCN Red List of Threatened Species. [Available online at . Consulted on 1 January 2012].
Revenga, C., Brunner, J., Henninger, N., Kassem, K. and Payne, R. (2000) Pilot Analysis of Global Ecosystems: Freshwater Systems. World Resources Institute. Wa shington, DC, USA.
Ruiz-García, M., Murillo, C., Corrales, C., Romero-Alean, N. and Alvarez-Prada, D. (2007) Genética de Poblaciones Amazónicas: La historia evolutiva del jaguar, ocelote, delfín rosado, mono lanudo y piurí reconstruida a partir de sus genes. Animal Biodiversity and Conservation 30: 115-130.
Seber, G. A. F. (1982) The Estimation of Animal Abundance and Related Parameters. Second Edition, MacMillan, New York, USA.
Trujillo, F. (1994) The use of photo-identification to study the Amazon river dolphin, Inia geoffrensis, in the Colombian Amazon. Marine Mammal Science 10: 348-353. http://dx.doi.org/10.1111/j.1748-7692.1994.tb00489.x
Trujillo, F., Portocarrero-Aya, M., Gomez-Salazar, C., Diazgranados, M. C., Castellanos-Mora, L., Ruiz-García, M., Caballero, S. (2010). Status and conservation of river dolphins Inia geoffrensis and Sotalia fluviatilis in Colombia. Page 99 in Trujillo, F., Crespo, E., Van Damme, P. A., and Usma, J. S. (Eds) The Action Plan for South American River Dolphins 2010 – 2020. WWF, Fundación Omacha, WDS, WDCS, Solamac, Bogotá, Colombia.
UNEP (2004). Barthem, R. B., Charvet-Almeida, P., Montag, L. F. A. and Lanna, A.E. Amazon Basin., GIWA (Global International Water Assessment) Regional Assessment 40b. University of Kalmar, Kalmar, Sweden. [Available online at<http://www.unep.org/dewa/giwa/areas/reports/r40b/giwa_regional_assessment_40b.pdf>].
Vidal, O., Barlow, J., Hurtado, L., Torre, J., Cendon, P. and Ojeda, Z. (1997) Distribution and abundance of the Amazon river dolphin (Inia geofrensis) and the tucuxi (Sotalia fluviatilis) in the upper Amazon River. Marine Mammal Science 13(3): 427-445. http://dx.doi.org/10.1111/j.1748-7692.1997.tb00650.x
Whitehead, H. (2009) SOCPROG programs: analysing animal social structures. Behavioral Ecology and Sociobiology 63: 765-778.
Wilson, B., Hammond, P. S. and Thompson, P. M. (1999) Estimating size and assessing trends in a coastal bottlenose dolphin population. Ecological Applications 9:288-300. http://dx.doi.org/10.1890/1051-0761(1999)009[0288:ESAAT]2.0.CO;2
LicenseAuthors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).