Guiana’s dolphin (Sotalia guianensis) was known until 2007 by its common name of marine tucuxi. It was recognized as the marine ecotype of a single species distributed in the Atlantic coastal areas of Central and South America, as well as in the Amazon River and its tributaries. The concept of one species with two ecotypes, one marine and one riverine, was changed based on morphological characteristics and genetic divergence. Although the number of studies on both species has increased in the last decade, they still remain listed as “Data Deficient” by the IUCN. The majority of these studies have been conducted in Brazil, and as a result, the populations from there are known fairly well and their status is not classified as endangered. In Colombia, Guiana’s dolphin was designated as Vulnerable in 2005 by the Ministry of Environment and Territorial Development of Colombia. The main reasons that gave support to this resolution were: a suspected and/or observed reduction in population size over the last 10 years based on a decline in area of occupancy and/or quality of habitat, and actual levels of exploitation.
        It seems like yesterday when I arrived in 2002 in Sarasota, asking the Sarasota Dolphin Research Program for help to conduct research with Guiana’s dolphin in Colombia. SDRP team members offered their knowledge, training, support and care for this project from the beginning. Without their support this project would not be the longest ongoing project conducted with marine dolphins in Colombia. The main goal of this project is to advance knowledge of the ecology of the Guiana’s dolphin in the Gulf of Morrosquillo, Colombia, and to use this knowledge to develop guidelines for the management and long-term conservation of this species and its ecosystem.
        For those who are not familiar with this species and its habitats, the question of why or how we chose this specific area in Colombia to conduct research may arise. For 30 years the Gulf of Morrosquillo has been the only area in Colombia where Guiana’s dolphins have still been reported. It may be the only area in Colombia where this species still resides. Therefore, it is extremely important for the conservation of this species and the ecosystems where it is found in Colombia, to conduct studies in this area to determine if a population decline has occurred or is occurring. An understanding of the basic species’ needs in this region is required for its survival. It is necessary as well to identify the principal causes for habitat loss in the study area and to recognize how they may affect directly or indirectly the dynamics of this species.
       

Releasing a Guiana's dolphin after illegal collection by an aquarium in Isla Palma, Morrosquillo Guilf, Colombia.

        From November 2002 through June 2006, 194 boat survey days were accomplished in the southern area of the Gulf of Morrosquillo. The surveys were made during the three climatic seasons: rainy, dry, and semi-dry, and covered approximately 8,226 km. The data collected include: environmental, behavioral, photographic, acoustic, and carcass. We have learned so much about this species in Brazil and Colombia in recent years. We know now, for example, that the different communities adapt to local geomorphologic characteristics, showing a high grade of plasticity and social learning. We also learned that it is impossible to generalize about suitable conservation methods for this species since the threats and ways that Guiana’s dolphins respond to them vary for each population. A strong tendency for site fidelity and permanent residency seems to be the common for this species along its distribution, but the number of individuals in a certain area at any moment depends on the carrying capacity. Guiana’s dolphins are strongly associated with estuarine ecosystems (mangrove areas), they feed and reproduce in these areas, and their survival is connected to the future of these ecosystems. We cannot separate the vulnerability of this dolphin species and the vulnerability of its coastal ecosystems. Two of the results of this study showed a decline in the number of sightings compared to previous reports from the area and a probable shift in their distribution and habitat selection caused mainly by habitat loss (anthropogenic origin).
        So, what are we doing to minimize the problem? At the moment we are analyzing data to gain basic knowledge on Guiana’s dolphins in the study area. We are going back to the field in 2009 and 2010 to collect more data, and we aim to expand the study area with the help of Colombian students who are interested in continuing research with this species. In addition, we aim to develop a Conservation Plan by the end of 2010 that includes a management and monitoring plan in the southern area of the Gulf of Morrosquillo, having the support of the Colombian Government and the local community. Our plan is to propose an area of special management for this species in this area of Colombia and in this way to initiate the protection of the coastal marine ecosystems in this country.
        Many thanks for the funding received by: CVS (Colombia), Cetacean Society International, Conservación Internacional (Colombia), Chicago Zoological Society’s Chicago Board of Trade Endangered Species Fund, Iniciativa de Especies Amenazadas “Programa de Becas Jorge Ignacio Hernández-Camacho” (Colombia) and private funds.