FAD Editorial

ÔWhy do tuna gather around FADs? How long do tuna stay near FADs? Why do some FADs seem to attract more tuna than oth-ers?Õ These are some of the many questions which interest researchers working for the ECOTAP (Tuna Behaviour Study through Acoustics and Longline Fishing) programme in French Polynesia. Pascal Bach and six other scientists participating in the programme summarise (p. 3) the preliminary results obtained during experimental fishing carried out in the vicinity of FADs. Through concurrent use of ultrasonic telemetry to track tuna and acoustic surveys to observe the surrounding environ-ment, these researchers have demonstrated the important effect which the biological environment has on horizontal and vertical tuna movements. A large-scale study was carried out by Jean-Philippe Detolle and four other scientists in La Reunion Island in the Indian Ocean for the purpose of optimising FAD costs and lifespans. In addition to the technical options proposed following an analysis of all the crit-ical points in the fabrication of mooring lines, the authors address FADsÕ importance to the continuation and development of arti-sanal fishing activities on the island. The extract selected for this publication (p. 19) covers the social and economic aspects of FADs through a study of their effects on the number of working fisher-men, catches and income. Oddly enough, few studies of this kind exist, although they are, in fact, essential when it comes to con-vincing governments and possible institutional donors of the mer-its of continuing FAD programmes. Again in the same region, Michel de San, one of the designers of a type of FAD which uses a surface array of small trawl buoys, summarises experiences with FADs in the Western Indian Ocean on page 24. In that part of the world, the FADs deployed are sim-ple to make and costs are kept down to the bare minimum. Fishing techniques there are very similar to those used in th