Parasites of billfish in eastern Australian waters

Fifty-two sailfish (Istiophorus platypterus), 63 black marlin (Makaira indica) , 1 blue marlin (Makaira mazara) and 3 striped marlin (Tetrapterus audax) were examined for parasites between 1987 and 1989.Fish were obtained from gamefishing tournaments, club competitions, professional charter operations and research cruises. Black marlin were collected from fishing grounds near Lizard Island, Cairns, Dunk Island, Cape Bowling Green and Cape Moreton. Sailfish were collected from Dunk Island, Cape Bowling Green, the Whitsunday Islands and Cape Moreton. The blue marlin and striped marlin were collected from Cape Moreton.All external, visceral and gill metazoan parasites were removed, or dissected out, counted and identified using a compound microscope. The distribution of parasites on the host was recorded. Stomach contents were collected and identified. Weight, body length, sex, reproductive status (immature or mature) and spawning status were also recorded for each fish examined.Parasites were also classified as either permanent, semi-permanent or temporary according to their probable longevity on the host. This research was undertaken to evaluate parasites as natural population tags in sailfish and black marlin, by examining differences in parasite abundance and parasite faunal complements in fish caught over a wide geographical range.