Gabon issued in 1991 four stamps which shows us some traditional fishing methods in the country, the 175F stamp has a dugout canoe on it what I believe is used in rivers and coastal swamps. The other three stamps show trap fishing, gillnet fishing and seine net fishing but shows not any watercraft.
The man in the dugout is fishing with a trammel net of which Wikipedia gives: A trammel is a fishing net with three layers of netting that is used to entangle fish or crustacea. A slack central layer with a small mesh is sandwiched between two taut outer layers with a much larger mesh. The net is kept vertical by the floats on the headrope and weights on the bottom rope
Gabon 1991 175f sg1094, scott717.