Giant otter | adibarocas

Giant otters live in South America' s freshwater ecosystems. They are top carnivores, feeding on fish of various sizes. The species, which recently was close to extinction, is listed as Endangered by the IUCN. Giant otters are sensitive to more recent threats, mostly related to the effects of human activity on Amazon freshwater environments.

Our project is based in Peru, especially the Madre de Dios province. One of the main potential threats it focuses on is informal, small scale gold mining. Mining is widely practiced in Amazon lakes and rivers and has several impacts on the riparian and aquatic environments by the release of mercury, the production of engine noise and bank habitat deforestation. We study giant otter populations in mined areas and also in the adjacent Manu National Park. Both of these areas have high conservation value because of their increased biodiversity.

Our work includes behavioral observations and monitoring of several giant otter groups. In a recent publication, we assessed how giant otters respond to distinct types of human activity. We found that, when ecotourism is responsible and strictly regulated, giant otters may become habituated to the presence of humans and show reduced defensive behavior. However, in areas with extractive activities, such as commercial fishing and gold mining, giant otter tend to avoid humans and keep their distance.

We also catch and sample fish, on which giant otter diet is based, to understand their abundance and mercury levels in oxbow lakes. In a recent paper, we found that in Madre de Dios fish abundance and biomass are considerably lower outside protected areas. The main fish species found in protected oxbow lakes were carnivorous piranhas, whereas in lakes exposed to mining and fishing, fish who feed on detritus were the most frequent.

Our long-term presence in both Manu National Park and unprotected oxbow lakes outside it enables us to gain insights on the specific processes by which gold mining drives habitat deterioration. An example is our assessment of water quality, which indicates that levels of dissolved oxygen and transparency are lower in lakes with human activity. We also used a drone to assess the giant otter's aquatic and terrestrial habitats. The resulting paper suggests that giant otters prefer well-drained bank areas with dense forest canopy cover, and open water and fallen logs in the water. Our ongoing analyses are aimed at examining the influences of environmental factors and human activity on giant otter abundance, survival and reproductive success.

The giant otter project also works with local communities in the Madre de Dios gold mining corridor to understand their perceptions towards giant otters and Amazon freshwater ecosystems. Since 2018, we have an educational presence in these places. Our community team works in local schools and conducts environmental education workshops. Our goal is to promote a better understanding of local freshwater ecosystems and the best ways conserve them.

Our recent publication examines how gold mining and the state of the aquatic environment are perceived by local people, and how likely they are to contribute in conservation initiatives. Opinions and perceptions are mixed, but it appears that local gold miners are concerned for the state of rivers and animals and are willing to paarticipate in actions that promote change and make their activities more sustainable.

During 2021, our community team started a recycling project, in participation with the municipality of Laberinto, involving several primary schools in the area. In addition, workshops are conducted, in which students learn about the aquatic ecosystems surrounding them and use art to draw the animals and plants they are familiar with.

This project is led by the San Diego Zoo Wildlife Alliance, in collaboration with the WildCRU unit from the University of Oxford.