In 1963 the director general of the 'Office de la Recherche Scientifique et Technique Outre-Mer' (ORSTOM) asked me to form a well structured team of hydrobiologists based at Fort-Lamy (now N'Djamena) where a laboratory could be built as a branch of the already existing ORSTOM Center. The International Biological Program, IBP, had at this time recommended an integrated study of ecosystems selected in proportion to their representation of a particular zone or ecological conditions. I took this opportunity to propose Lake Chad as the model of a tropicallake in a semi-arid c1imate as part of the activity of the section Productivity of freshwater communities (PF). With the efficient help ofDr B. Dussart a research program was established involving the establishment of a permanent team of ten researchers in Chad. Apart from myself, ORSTOM only had three hydrobiologists: Mr R. Gras, Mr G. Loubens and Mr A. Iltis. These valuable researchers who had been working for the 'Centre Technique et Forestier Tropical' and had acquired considerable experience in African freshwaters, unhesitatingly accepted to join me at Fort-Lamy. It was necessary to enlarge this team with so me young and enthusiastic collaborators, namely, Mr C. Leveque, Mr C. Dejoux, Miss S. Duwat, Mr L. Lauzanne and Mr. J. R. Durand, later joined by Mr J. P. Carmouze and Mr J. Lemoalle.