Counting river dolphins in Peru
The fourth of a five-stage expedition to establish river dolphins numbers in the Amazon and Orinoco Rivers and their tributaries, South American scientists counted 818 pink dolphins (Inia geffrensis) and grey river dolphins (Sotalia fluviatilis) in 410 sightings.
The largest groups of the dolphins were seen at river confluences where fish are in most abundance.
“Preliminary observations show that the dolphin’s habitat in Peru appears to be in a good state,” said Freddy Arévalo with the Wildlife Conservation Society in Peru. “This state of affairs owes much to the conservation initiatives and sustainable resource management programme which have been implemented in the area, including those of WCS and WWF.”
The results in Peru were significantly more than the 131 pink dolphins spotted on the previous part of the expedition on Colombia’s Meta River.
“The Meta River has been hit hard by pollution and over-fishing,” said Marcela Portocarrero, a scientist from the Omacha Foundation, who is taking part in the dolphin survey. “This has created a marked decline in fish stocks, made evident by low numbers of dolphins, who depend on fish for food.”
The first leg of the survey recorded 270 dolphins on the Orinoco River in Venezuela in June 2006 and only 40 in Ecuador on the Lagarto Cocha, Cuyabeno and Yasuni Rivers in July 2006.
A fifth expedition is planned for Bolivia and a possible sixth expedition on the Amazon River from Peru via Colombia to Brazil in January 2007.
The overall aim of the survey is to gather data on one of the endangered freshwater species in the world in order to design a management and monitoring plan, as well as get to know the state of the rivers and watersheds of some of South America’s largest rivers.
“This dolphin census gives us the wide view of river dolphins in South America,” said José Saulo Usma, WWF Colombia’s Freshwater Coordinator. “This is a first step to build an up-to-date database for the species, something that is fundamental to our future conservation work.”
• The South American river dolphin survey is an initiative led by the Omacha Foundation, with support from the Wildlife Conservation Society, Whale and Dolphin Conservation Society and WWF Colombia.
• The pink river dolphin (Inia geoffrensis), also known as the boto, is found in lowland fast flowing, white-water rivers, clearwater or blackwater rivers. The species is also present in the largest tributaries, lakes, confluences and seasonally flooded forests. It depends on healthy fish populations for its survival. Historically, the boto has been spared human persecution because of the belief that it has special powers. Today however, it is increasingly viewed by fishermen as an unwanted competitor for fish. The boto can get tangled up in fishing nets, or suffer wounds by colliding with boats.
• In addition to spotting the pink river dolphin, scientists are also on the look out for the grey river dolphin (Sotalia fluviatilis), a dolphin species darker and smaller than the boto, with a shorter snout and a distinctive triangular dorsal fin.
For further information:
Julio Mario Fernández, Communications Coordinator
Tel + 57 2 558 25 77