This research aimed to quantify the methyl esters of linoleic (LA), gamma-linolenic (LNA), arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids in the muscular tissue and orbital cavity of farmed tambaqui (Colossoma macropomum) and in those caught in the Brazilian Amazonian Area during two periods. For the farmed fish, the amounts of LA, LNA, AA, EPA, and DHA found in the muscle were 208.0, 12.4, 57.9, 5.0, and 25.1 mg/g, respectively. The amounts of these FA in the orbital cavity were 103.4, 6.6, 20.0, 4.4, and 8.1 mg/g for LA, LNA, AA, EPA, and DHA, respectively. For the fish caught during the flood period, the LA, LNA, AA, EPA, and DHA levels were 297.3, 50.7, 32.3, 3.8, and 14.1 mg/g in the muscle and in the orbital cavity were 259.7, 40.3, 10.8, 5.5, and 9.3 mg/g, respectively. For the fish captured in the dry season the levels of LA, LNA, AA, EPA, and DHA in the muscle were 262.0, 48.0, 157.6, 9.3, and 40.2 mg/g and in the orbital cavity were 102.5, 15.7, 24.6, 7.0, and 8.9 mg/g. According to their contents of AA, EPA, and DHA, tambaqui captured in the dry season can be considered as a rich source of EFA. The adipose tissue of the orbital cavity did not show sufficiently high EPA and DHA contents to classify it as a better source of FA than the muscle.
