JOHANNESBURG (Reuters) - The world's largest gorilla sub-species has seen its population fall 77 percent over the past two decades, a trend linked to illegal mining for coltan, a key mineral used in the production of cell phones and electronics, a new report has found.
Grauer's gorilla, the planet's biggest primate which can weigh up to 400 pounds (180 kgs), is found in the eastern Democratic Republic of Congo, where minerals have been plundered for decades under the smokescreen of conflict and instability.
A report this week by the Wildlife Conservation Society (WCS) and Fauna & Flora International found that its numbers had fallen to 3,800 from an estimated 17,000 in 1995.
"One of the primary causes of the decline in Grauer's gorilla numbers has been the expansion in artisanal mining for coltan and other minerals. Most of these artisanal mining sites are remote, which means that the miners often turn to local wildlife for food," the organizations said in a statement.
Artisanal mining often involves the illegal extraction of minerals by hand or other makeshift methods.
"Although protected by law, gorillas are highly prized as bushmeat due to their large size and because they are easily tracked and killed as they move in groups on the ground in their small home ranges," the groups said in the statement.
The report says three areas are now key to the survival of the sub-species - Kahuzi-Biega National Park, near the Rwandan border, the adjacent Punia Gorilla Reserve, and the Usala Forest, which is remote but unprotected.
Estimates of the animal's numbers were based on widespread field surveys of ground nests and other signs as well as data collected from rangers and local communities.
The reports authors say the sub-species status should now be labeled as "critically endangered", the highest risk category assigned by the International Union for Conservation of Nature, which means a wild animal faces a very high risk of extinction.
To reverse the decline of Grauer's gorilla, the report says militia groups operating in the lawless region must be disarmed.
It also calls for activists and consumers to: "Lobby cellphone/tablet/computer companies and others to ensure that source minerals from this region are purchased from mining sites that do not hunt bushmeat and are conflict free."
There have been a lot of efforts to reduce the amount of "conflict" or "blood" minerals coming from the region, including a provision in the 2010 Dodd-Frank act obliging U.S.-listed companies to ensure their supply chain was free from tainted Congolese minerals, specifically gold, coltan, tin and tungsten.
The eastern Congo and neighboring Rwanda and Uganda are also home to the more famous mountain gorilla which is also extremely endangered.
Gorillas are threatened throughout their range in Africa's tropical forests and are among humanity's closest living relatives, along with the other great apes, chimpanzees, bonobos and orangutans.
Editing by Raissa Kasolowsky