Trial setting of deep longline techniques to reduce bycatch and increase targeting of deep-swimming tunas


Beverly, S., Robinson, E., Itano, D.



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SCTB17 Working Paper

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Pelagic longlines were weighted with lead weights, enabling them to fish deeper in the water column than traditional pelagic longlines.  Weighted longlines caught 31 target species with a slightly higher catch per unit effort (CPUE) of 1.3 fish/100 hooks (49 kg/100 hooks) compared to traditional gear (38 target species and a CPUE of 1.08 fish/100 hooks or 41 kg/100 hooks).  Bigeye tuna CPUE for the weighted gear was higher, 0.95 fish/100 hooks (36 kg/100 hooks), than for traditional gear, 0.56/100 hooks (21 kg/100 hooks).  Swordfish CPUE was very similar for weighted (0.3 fish/100 hooks or 17 kg/100 hooks) and traditional (0.25 fish/100 hooks or 14 kg/100 hooks) gear.  This technique could be used to reduce sea turtle and other bycatch species interactions, however this was not tested during this initial trial study.