Pr. Fredj has been the head of the Laboratoire d'Oceanographie Biologique and director of the Centre de Ressources Informatiques de l'Université de Nice - Sophia Antipolis (1992-1996). He was the president of the Benthos Committee of the International Commissions for the Scientific exploration of the Mediterrannean Sea (ICSEM) from 1991 to 1996.
Pr. Fredj is a specialist in Mediterranean Biodiversity. He has created (with a network of 35 contributors from 5 European countries) the MEDIFAUNE data bank (Mediterranean Marine Fauna) which contains factual data on 5366 species of the Mediterranean and Black Sea fauna, recorded since 1758, a pilot realization for biological data banking.