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.

1987年至1989年间，研究人员共收集52尾旗鱼（Istiophorus platypterus）、63尾黑枪鱼（Makaira indica）、1尾蓝枪鱼（Makaira mazara）及3尾条纹枪鱼（Tetrapterus audax）开展寄生虫调查。所有样本均源自海钓锦标赛、俱乐部赛事、专业包船捕捞作业及科研巡航。
其中黑枪鱼采集自蜥蜴岛、凯恩斯、邓肯岛、鲍灵格林角与莫顿角附近的渔场；旗鱼采集自邓肯岛、鲍灵格林角、圣灵群岛及莫顿角；蓝枪鱼与条纹枪鱼均采集自莫顿角。
研究人员对所有受试鱼类的体外、内脏及鳃部后生寄生虫进行剥离或解剖取材，经计数后通过复合显微镜完成种类鉴定，并记录寄生虫在宿主体内的寄生分布；同时采集并鉴定胃容物。此外，还逐一记录每尾受试鱼的体重、体长、性别、繁殖状态（未成熟或成熟）及产卵状态。
研究人员还根据寄生虫在宿主体内的预期存活时长，将其划分为永久性、半永久性与临时性三类。本研究旨在通过分析广泛地理范围内捕获的旗鱼与黑枪鱼的寄生虫丰度及寄生虫区系组成差异，评估寄生虫作为其自然种群标记的可行性。