This clip from BBC One's documentary series Human Planet shows what happens the one day a year when the Dogon people in Mali are allowed to fish in the sacred Lake Antogo in the village of Bamba. It only takes 15 minutes for thousands of fishermen to clear out the lake.
Thousands of fishermen empty lake in minutes - Human Planet: Deserts, preview - BBC One
This article from The Sunday Times describes the legend behind Lake Antogo:
Legend has it that the lake was discovered in ancient times by a young girl from Bamba village. She told her sister in the neighbouring village of Yanda about the profusion of fish, and her brother-in-law claimed the lake for Yanda. But her father staked a claim on it too, and tribal war broke out. Eventually her father and his fellow tribesmen won the battle, and even today only Bamba men can take part in the great fishing ceremony; the men of Yanda are forbidden.
This article from Reportage has more photos from the fishing ritual. It says "Antogo" is the name of the ritual, not the lake, and explains how the fish are distributed: "All fish captured will be put together and given to the oldest man of Bamba, who will ensure proper distribution among all villages."