[en] Lake Tanganyika is very rich in fish species. It is exploited by fishermen and by fish-eating birds often seen as competitors of man. An osteological study was undertaken to establish a methodological tool as a basis to studying the diet of fish-eating birds. Fish were collected, grouped by family. They were then transported to the laboratory to extract features of the cranial bones of each species or genus. An identification key to these bones has been prepared based on the similarities and differences between these bones. Correlations between the length of bone characteristics and size of fish were calculated.