Deep-frozen longline and ice fresh-longline are the only two fishing gears used by Chinese fleets to catch tuna and tuna-like species in the IOTC waters. The total number of Chinese longline vessels operated in the IOTC waters in 2017 was 81. The number of active deep-frozen longline vessels increased from 54 in 2016 to 71 in 2017. The tropical tunas catch (bigeye and yellowfin tuna) of Chinese longline fleet in 2017 was estimated at 7,880 MT, 1,982 MT higher than that in 2016(5,898MT). The number of ice-fresh longline vessels decreased from 13 in 2016 to 10 in 2017. The albacore longline catch for 2017 was estimated at 3,646 MT, higher than in 2016 (1,920 MT). Both the logbook and observer programs are being implemented for the Chinese longline fleets. In 2017, four scientific observers were deployed on board longline vessels, and collected the data for both targeted and bycatch species as required.