The Guyana dolphin (Sotalia guianensis) is one of the smaller dolphin species and lives exclusively in South America along a narrow coastal strip from Honduras to Brazil. Due to its coastal distribution, this species is severely affected by human activities. In Venezuela, the main distribution areas are the Orinoco River and Lake Maracaibo. The World Conservation Union IUCN Red List classifies the Sotalia dolphin as potentially threatened (NT). At regional level, however, the species is classified as endangered. Due to the increase in fishing activity along its entire range and habitat destruction, it is feared that local populations are at risk of disappearing completely in the future. Lack of monitoring and control has dramatically worsened the situation for these dolphin populations.
Several genetic and morphological studies indicate that the Guyana dolphin population from Lake Maracaibo must be considered a distinct management unit due to its differences from the rest of the population. Lake Maracaibo has the highest bycatch rate for this species, with a mortality rate of 180 individuals per year. It is the only region in Venezuela where a dolphin species is exploited for human consumption. In addition, there are regular problems with the oil pipelines with catastrophic consequences for the environment. There are around 15 oil spills per year in Lake Maracaibo, which in turn results in contamination with heavy metals and other toxins. Initial studies have already shown negative effects on marine mammals.
Although studies on the population size, behavior and biology of the Sotalia guiana dolphin are available on a global level, such findings are unknown for the population in the Maracaibo. In order to better evaluate the extent of the bycatch problem, a monitoring program is important.
Successes and progress to date
Thanks to PROYECTO SOTALIA and YAQU PACHA, various studies have been carried out in Lake Maracaibo (13,000 km²) on the biology and endangerment of the Guyana dolphin since 2016.
For example, data on the number of animals killed by fishing has been systematically recorded since 2016 and consumption by the local population has also been documented. Based on these figures, the mortality rate can be better defined. In addition, tissue samples from dead animals are examined to determine possible contamination with mercury and heavy metals. This data is relevant to assess the health of this dolphin population, but also to demonstrate the risk to humans. Initial figures indicate that the levels of some harmful substances are particularly high, meaning that human consumption of the meat poses a health risk. In collaboration with other NGOs, a campaign has been launched to warn people against eating dolphin meat in order to protect Guyana's dolphins.
Equally important is the recovery of so-called ghost nets, which repeatedly cause animals to become entangled and subsequently die. This work is carried out in cooperation with various other NGOs, including the shark research center CIT Venezuela.
In the area of information and education, a poster on the impact of heavy metals on the ecosystem of Lake Maracaibo was designed with the support of YAQU PACHA and distributed to fishermen and other people living there. Informative posters have also been produced and distributed in recent years. Visiting schools is another important part of the environmental education work.
On the occasion of the International Day of the River Dolphin, our partners Proyecto Sotalia held an information event in Venezuela.
Many interested people came to this event and our biologist Yurasi Briceño reported on our work to protect the dolphins and our activities in Venezuela.
Ethnobiology of the Guyana dolphin(Sotalia guianensis) and traditional knowledge of artisanal fishermen in the state of Espírito Santo, Southeast Brazil
The Guyana dolphin(Sotalia guianensis) is a dolphin threatened by accidental capture in gillnets used in artisanal fisheries in the central coastal mesoregion of Espírito Santo (ES) in southeastern Brazil.
There is little information about these dolphins for the state of Brazil. The Brazilian National Action Plan for the Protection of Endangered Whales and Dolphins (PAN dos Cetáceos Marinhos) emphasizes the urgent need to collect data on traditional knowledge for the Espírito Santo coast. The objective of this study is to identify, with the knowledge of fishermen, the interactions between Sotalia dolphin and artisanal fishing in the areas where they occur, for the mesoregion of the central coast of Espírito Santo. In addition, environmental awareness actions will be carried out with children from public schools in fishing communities.
With the results obtained, it will be possible to understand the areas of use and human interactions with the species and achieve the objectives of the PAN of Marine Cetaceans, the Decade of the Oceans and the Sustainable Development Goal No. 14 "Life in Water" of the 2030 Agenda. This part of the Sotalia dolphin project is carried out in collaboration with our partners ECOLOGIA HUMANA DO OCEANO.
Team Latin America | Project Sea Otter | Project Chilean Dolphin | Chilean Dolphin | 30 Years YAQU PACHA e.V. | Information about the dolphin species | Species protection | Project Manatees | Project Vaquita | Project Bottlenose Dolphin | Project La Plata Dolphin | Expedition to the Inias in the Rio Casiquiare