The hippo population declined most dramatically in the Democratic Republic of the Congo. By 2005, the population in Virunga National Park had dropped to 800 or 900 from around 29,000 in the mid-1970s. The decline is attributed to the disruptions caused by the Second Congo War. The poachers are believed to be Mai-Mai rebels, poorly paid Congolese soldiers, and local militia groups. Reasons for poaching include the belief that hippos are harmful to society, as well as financial gain. However, as of 2016, the Virunga hippo population appears to have increased, possibly due to greater enforcement and cooperation between fishermen and park authorities. The sale of hippo meat is illegal, but black-market sales are difficult for Virunga National Park officers to track. Hippo meat is considered a delicacy in some areas of central Africa and the teeth have become a valued substitute for elephant ivory.