Résumé
The amounts of billfish taken as bycatch by various fishing modes and as bycatch by the Spanish and French tuna purse seiners in the eastern Atlantic Ocean were studied. Bycatch data were collected by observers at sea from June 1997-May 1999. Billfish bycatch by purse seiners generally is very low, and is less than 10% of the total billfish catches currently reported. Simulation modeling showed that the temporary moratorium on fishing with fish aggregating devices (FADs), required in the European purse-seine fishery in this region, resulted in lower incidental catches of marlins, but increased bycatch of sailfishes. Indices for evaluating marine fish conservation status are difficult to devise. An ecosystem approach that incorporates biological and socioeconomic criteria is essential for large pelagic resource management.