| Remarks |
Acoustic tagging studies (Ref. 4683) suggest that blue marlin primarily inhabit the surface mixed layer, which is the relatively uniform layer of water between the surface and the top of the thermocline where water temperatures start to drop suddenly (Ref. 6390). Studies have also suggested that fish spend more time close to the surface at night than during the day (Ref. 6390).
In the Pacific Ocean, blue marlin concentrate year-round in tropical waters, but a part of the population undertakes large seasonal movements away from equatorial waters to about 30°S (Ref. 30354). These movements, mostly undertaken by males of 35-75 kg (Ref. 30354), occur as waves in the northern and southern hemisphere summers (Ref. 6390). Fish moving into eastern Australian waters in the summertime are probably part of 1 of these migrations (Ref. 6390).
Blue marlin also live year-round in the Eastern Indian Ocean between northwestern Australia, Java and the Lesser Sunda Islands, with maximum concentration during the Northwest Monsoon (November to April), and between the equator and 13°S during the Southeast Monsoon (April to October) (Ref. 6390).
Known to feed in and near surface waters, but sometimes take food in relatively deep waters as is shown by the presence of deep-dwelling squirrel fish (Holocentrus laeteoguttatus) in the stomachs of this species in Hawaii. |