The information comes from a civilian militia source and the fishermen's union.
According to the Fisheries Association, fighter jets bombed two islands on the lake.
40 Nigerian fishermen are missing and are believed to have drowned as a result of the attacks, according to fishermen who escaped, a union representative says.
Lake Chad stretches between Cameroon, Chad, Niger and Nigeria, and its many islands provide a haven for jihadist groups such as Boko Haram.
