Fishing gear and operation. All vessels included in the study operated with an American System longline (for details see Xxxxxxx et al., 2009). Branch (secondary) lines consisted of a snap, which connects the branch line to the mainline, a length of 2.0 mm monofilament top section followed by a 75 g weighted swivel, 4.5 m of 2.0 mm monofilament bottom section, and a size 9/0 offset hook. The research vessel gear replicated commercial fishing gear although lines set on the research vessel were shorter than those set on commercial vessels (360-450 hooks compared to 900-1,360 hooks, respectively). Line setting typically began just prior to sunset and was generally completed before midnight. Squid Illex argentinus bait was thawed a few hours before line setting began.
