Abstract
The continuous implementation of drifting Fish Aggregating Devices (dFAD) by tropical tuna fishermen in the early 1990s has impacted the species and size composition of the tuna catch as well as some components of the epipelagic ecosystem (e.g., sharks, turtles, etc.). In addition, the development of this fishing mode introduced a new uncertainty in stock assessment models as abundance indices derived from FAD-fishing cannot be calculated easily as the conventional unit of fishing effort (i.e., the searching time) traditionally used for free school fishing cannot be applied. For all of these reasons, the objective of the European Research project " Catch, Effort, and eCOsystem impacts of FAD-fishing " (CECOFAD) is to improve our understanding of the use of fish-aggregating devices (FAD) in tropical purse seine tuna fisheries and to provide reliable estimates of abundance indices and accurate indicators on the impact of FAD-fishing on juveniles of bigeye and yellowfin tunas and on by-catch species. We presented here the state of advance of the project in light of its objectives, the progress in recovery for non-conventional data and the first results.