Giant otter project update: gold mining, fish bites and hungry caiman

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Illegal gold mining activities and deforestation have severely affected the habitat of giant otters in the Peruvian amazon. However, the full extent of these human threats on giant otters are not well understood yet. People’s Trust for Endangered Species has teamed up with Adi  Barocas in Peru, to understand what is happening and what we can do to reverse their fortunes. In his latest blog post for us Adi gives us an insight into the perils of giant otter conservation!

Gold mining, fish bites and hungry caiman: the latest in giant otter conservation science effort

Group of otters

Our team, which runs the Giant Otter Conservation Project, has just completed our annual surveys of oxbow lakes in the gold mining zone of the lower Madre de Dios river. We documented diverse human activities, including fishing, hunting and gold mining, both within the oxbow lakes and in their vicinity. Pleasingly, we also found several giant otter groups, numbering 40 individuals in total. 


Fish sampling in Peru Photo credit: Adi Barocas

Evidence of otters was also found in Manu National Park and its adjacent areas. Gliding along the water in an inflatable rubber kayak, purchased with funds from PTES, the research team noted the welcome news that breeding had occurred in at least five giant otter groups. We will visit the mined and protected sites again in the rainy season to learn more about giant otter distribution and population dynamics.


We also continued our efforts to sample fish so we can understand what food resources the otters have access to and what their exposure risk to mercury, a toxic metal released into the air and water by gold miners, is. To examine their abundance, we captured fish in ten seasonal lakes. Every fish was measured and sampled for mercury analysis.

Fishing in oxbow lakes is no simple matter. Part of the work must be carried out at night, when most fish are more active. Several of the species, such as piranhas, are carnivorous and have razor-sharp teeth; they’re just waiting for an opportunity to bite our fingers when we remove them from the nets.

Black caiman photo credit: Adi Barocas

Hungry black caiman, who are abundant in our oxbow lakes, also pose a threat as they attempt to approach the nets for an easy meal. These large reptiles consistently need to be driven away from the nets. Luckily, the project’s dedicated Peruvian assistants and I managed to face these challenges with minimal injuries!

Thanks to PTES supporters we have been able to purchase the kayak, the fishing nets and additional specialized gear needed for us to carry out this vital work.

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The Peru giant otter project is led by San Diego Zoo’s Conservation Institute, in collaboration with the WildCRU unit at the University of Oxford. It is funded by the People’s Trust of Endangered Species.

Support the work being done to save giant otters


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