Managing tropical tuna purse seine fisheries through limiting the number of drifting fish aggregating devices in the Atlantic: food for thought

This paper makes an analysis of the numbers of drifting fish aggregating devices (DFADs) in the eastern Atlantic Ocean and of the potential interest to manage purse seine fisheries based on limitations of FADs numbers. Potential risks of massive DFADs use are discussed. Numbers of FADs released by the French fleet (2004-2014 period) are now available; this paper estimates levels and trends of deployed and active FADs numbers. It is estimated that FADs numbers have been widely increasing during recent years, potentially reaching 18000 or more FADs today, and potentially resulting in an estimated 3.7 fold increase since 2004. Good knowledge of total numbers of DFADs is urgently needed to better estimate the fishing effort and capacity of DFAD fisheries. Future limitations in the number of DFADs could allow an efficient way to reduce FAD fishing effort. Following a precautionary approach, we suggest that ICCAT could consider setting a cap on the number of DFADs; this monitoring could be based on the year 2013. The objective would be to slow down the increasing trends observed in the overall fishing capacity of DFADs. Consequences of such measures should be carefully analysed to ensure the sustainability of the fisheries concerned.