The status of species in the wild is monitored by the IUCN (International Union for Conservation of Nature). This is the most up do date IUCN status on giant otters:
The status of Giant Otters is regularly monitored by its range countries. Of the 12 national assessments on the distribution and conservation status of the Giant Otter that were prepared, in two countries the species has been categorized in national Red Lists as Critically Endangered (Paraguay and Ecuador), in four countries as Endangered (Peru, Colombia, Venezuela, Bolivia), and as Vulnerable in Brazil; it is considered Extinct in Uruguay, and probably Extinct in Argentina. In the Guianas, the Giant Otter is also protected by law though this is rarely enforced. There was a strong consensus among workers on Giant Otter that it should be considered as Endangered on a continental level. The total global Giant Otter population size is low but, more critically, individual subpopulations are fragmented and most are small. Because of its conspicuous behaviour and social nature, this species is easy to extirpate and is therefore extremely vulnerable. It remains highly susceptible to hunting (though currently hunting of Giant Otters is not a common practice). The killing of individuals and entire groups continues in some areas where fishermen are active, including in protected areas. Moreover, the Giant Otter is intrinsically vulnerable to extinction: combined with low habitat resilience and the fact that only a quarter to a third of the total population reproduces, the species also shows late maturity, late breeding age, suspected low transient survival, and low cub survival – all are traits which limit Giant Otter recovery and re-colonization. Although widely distributed on a continental scale, overall they may occupy less than 5%, often less than 1% of a given watershed. This means that changes in this specific habitat, or impacts there-in, will have severe effects even if only a fraction of the overall area is affected. Rivers are roads into the forest, this is where people settle, where gold mining takes place, where there is competition for fish or overfishing, where “green” energy can be harvested, where climate change will have strong impacts, where contamination can be spread rapidly, and so on. This vital link to rivers and wetlands renders the Giant Otter much more susceptible than most other comparable large predators of the Amazon, such as the Jaguar.