South America River Dolphin Survey
Yearlong Study of Amazon River Pink Dolphins and Tucuxi Ends
A unique survey of South America's river dolphin populations is giving a clearer picture of the status of two threatened species and the rivers they live in.
The Amazon River is well known as the water source for one of the world’s largest rainforests. But it is also home to the endangered pink river dolphin (Inia geoffrensis). The results of an intensive survey initiated by Fundacion Omacha and supported by the Whale and Dolphin Conservation Society (WDCS), Fundacion LaSalle, the Wildlife Conservation Society (WCS) and the World Wildlife Fund (WWF) will go a long way to determining the status of the boto (as the pink river dolphin is known locally) as well as providing baseline information on the grey river dolphin or tucuxi (Sotalia fluviatilis), another freshwater dolphin of the same area. Techniques and protocols will be compared with those used in other parts of the world where freshwater dolphins are found.
What the Survey Will Tell Researchers
Beginning in May of last year, the survey took scientists to Bolivia, Columbia, Ecuador, Peru and Venezuela. The Orinoco River watershed was searched first, then the Amazon basin. The surveys are part of an program to survey for freshwater dolphins around the world. Similar surveys have taken place in Asia. From these projects protocols and techniques for surveying for these species will be internationally standardized.
The boto is listed as Vulnerable by the IUCN so this study will provide important information which may prevent the species from going the way of the baiji. Researchers from Fundacion Omacho had already done mark recapture studies of the pink dolphin in the Amazon River. These studies, in this case more correctly called sight-resight as they compare pictures of dolphins previously photographed with present sightings, provide background for the survey. They have photo-id of over 150 pink river dolphins from both the Amazon and Orinoco Rivers. Combining the details from the survey with the ongoing id work provides valuable data necessary to develop species and habitat protection plans. Because the tucuxi, which is IUCN listed as Data Deficient, inhabits the same watersheds information crucial to determining their actual numbers and overall status will help assign appropriate listing as well.
Threats and Conservation Efforts
Both species face threats from habitat loss from deforestation and hydroelectric plant development, entanglement in fishing gear and mercury contamination from mining. An additional threat to the boto is the use of the dolphins as bait in the mota fishery. By determining more about South America's freshwater dolphins, appropriate habitat can be protected. Education programs for children in settlements near the rivers as well as for fishermen who often believe that the freshwater dolphins are competing with them for food are another aspect of Fundacion Amacha’s work to protect these rare dolphins.
Photo Credit: Lunchi
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