Résumé
In 2011, the French purse seine fishing fleet of the Indian Ocean was composed of 8 large size vessels that represented a total carrying capacity of about 8,000 t. Catches reached a total of 43,000 t and were composed of 50%, 42%, and 8% of yellowfin, skipjack, and bigeye, respectively. After a period of increase during 2006-2008, the fishing effort of the fleet has been decreasing to reach a minimum of 1,800 searching days in 2011. The decrease in effort was associated with a contraction of the fleet fishing grounds in the recent years and mainly characterized by a strong decrease in the number of sets made on free-swimming schools; a total of 1,800 fishing sets being made in 2011 compared to about 4,200 y−1 in the mid-2000s. Hence, the percentage of sets made on FAD-associated schools steadily increased since 2004 to reach more than 65% in 2010-2011, FAD-fishing resulting in 75% of the total catch of the French purse seine fishing fleet in 2011. Species-specific catch rates (in t per searching day) on FAD-associated schools reveal increasing trends over 1981-2011 with high interannual variability while no clear trend is apparent in the time series of catch rates on free-swimming schools. The year 2011 is characterized by a large proportion of yellowfin in the catch on FAD-associated schools that might indicate a good recruitment. For both fishing modes, the mean weight in the catch of the 3 tropical tunas has decreased since the mid-2000s with values in 2011 equal to 7.1 kg, 2.4 kg, and 5.4 kg for yellowfin, skipjack, and bigeye, respectively.