A comparison of catches of swordfish, Xiphias gladius, and other pelagic species from Canadian longline gear configured with alternating monofilament and multifilament nylon gangions

Tests were conducted aboard Canadian longline vessels targeting swordfish (Xiphias gladius) to determine if there were differences in the catch rates and size composition of swordfish and bycatch species caught by monofilament and multifilament nylon gangions.  No significant differences in the mean lengths of swordfish were found between the two nylon gangions but catch rates did differ significantly, with more swordfish caught on the monofilament gangions. There was also a significant difference in catch rates between the two gangions for blue sharks (Prionace glauca) and pelagic stingrays (Dasyatis violacea), with more animals caught on monofilament gangions. There was no significant difference in catch rates between gangions for mako sharks (Isurus oxyrinchus), white marlin (Tetrapturus albidus) or loggerhead sea turtles (Caretta caretta).