Descente de la Tsiribihina
The descent of the Tsiribihina is proposed in (motor boat) barge or by canoe. Barges, certainly faster and perhaps more "comforts", are polluting and noisy. I therefore urge you down the River in a dugout canoe (on 2.5 days, 2 nights until Antanambo) to discover the fauna and flora Malagasy!
During this ballad in the dugout: discovery of beautiful landscapes, animals (crocodiles, chameleons, herons and other birds, etc.), stop at the waterfall of Anosinganpela and encounter with the population of the surrounding villages. A canoe is dedicated to the kitchen and for the fish, they shop at the option of the canoes that sell. Of course, nights in bivouac on sand banks that allow you to enjoy the sunsets and the raising of the Sun: everything simply amazing!
The descent of the River starts at Miandriavazo, prefer direct contact with the dugout (from the dugout, being specified that little smart also advises the hotel Baobab hotel).
A drawback on the descent of the River in a dugout canoe you gave me but I've not experienced: some canoes would be attacked, so I can only recommend you to organizations that know their business, in order to avoid stop in isolated locations, etc.
The descent of the Tsiribihina River in a dugout canoe is a way to transport slow (slow travel) and non pollutant (respect the environment and people in the surrounding villages). In these raids, the paddlers stop in their village to bring food to their families.