During the 1950s and 1960s, a campaign was conducted in order to eradicate sources of disease, and over 1 million marmots were exterminated. Losses in prey species have in turn affected predators such as bears, wolves and snow leopards, as well as large predatory birds such as vultures (including Egyptian, black and griffon vultures). Declines have also been reported in many indigenous fish species in Lake Issyk-Kul as a result of overfishing.