The Semliki harpoon, also known as the Katanda harpoon, refers to complex harpoon heads carved from bone. It is from an archaeologic site on the Semliki River

Semliki River

Semliki River is a major river in Central Africa. It flows northwards from Lake Edward in the Democratic Republic of the Congo, across the Uganda border, through western Uganda in Bundibugyo District, near the Semuliki National Park. It empties into Lake Albert at...

 in the Democratic Republic of the Congo

Democratic Republic of the Congo

The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...

 (formerly Zaire) which dates back 90,000 years.

It seemed to substantiate that fishing and an "aquatic civilization" was likely in the region across eastern and northern Africa during the wetter climatic conditions of the early to mid-Holocene, as shown by other evidence at the lakeshore site of Ishango.

The site is littered with catfish bones and the hooks are the size to catch adult catfish, so investigators suspect the fisherman came to the site every year "to catch giant catfish."

It is unlikely that the harpoons are much different than those used today (see reference for photos).
The archaeologic site coincides with the range of the Efé

Efé

The Efé are a group of part-time hunter-gatherer people living in the Ituri Rainforest of the Democratic Republic of Congo. In the depths of the forest they do not wear much clothing, using only leaf huts as shelter for their bodies in the intense heat. The Efé are Pygmies, and one of the shortest...

 Pygmies, which have been shown by mitochondrial dNA analyses to be one of the oldest races still existing on earth.