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Tuna and tuna like species are important fish stock. Among tropical tunas, yellowfin and skipjack are the two important species. Different gear settings are used to catch tuna and tuna like species as fishers change fishing grounds moving from coastal to offshore and in the high seas. Different gear settings result in different catch and therefore, has proven as a mitigation measure for reducing entanglement of incidentally caught species. The impact of different gear setting on target catch species has not been determined. Therefore, assessing and providing capture rates for target tuna species is critical for gear settings to be considered an appropriate conservation and management measure. This paper provides capture rates and makes comparisons of target catch with different gear settings using the data collected by four trained skippers (on 15-20 m vessels) actively engaged from 2013-2017. During this period, a total of 3,874 drift gillnet sets was monitored. Two gear settings using multifilament gillnets were used: surface and subsurface gillnets. Surface gillnets were deployed at the surface, whereas “subsurface” gillnets were deployed at 2 meters below the surface (net height varied from 10 to 14m). A total of 304,952 tunas were captured (68.8% of the total catch, all species included). A total of six species of tuna was recorded as target catch, yellowfin tuna (Thunnus albacares), Skipjack (Kotsuwanis pelamis), longtail tuna (Thunnus tonggol), frigate tuna (Auxis thazard thazard), Kawakawa (Euthynis effinis), and Bullet tuna (Auxis rochei). Captures rates (CPUE) were calculated for tropical tuna species for both gear settings. Overall, tuna CPUEs in surface and subsurface gillnets were not significantly different, whereas incidentally caught species, were higher in surface settings and lower in subsurface settings. The results from the study are promising and other methods such as the use of electronic monitoring systems is encouraged for expanding studies elsewhere, in addition to also studying the gear behavior and may be considered as a potential conservation and management measure in gillnet fisheries.
