Fatty Acid Profile and Total Fat Content of Yellowfin Tuna (Thunnus albacares) from Three Major Fishing Zones

Introduction: Yellowfin tuna (Thunnus albacares) is one of the most commercially important tuna species worldwide, widely consumed for its recognized nutritional value, particularly its content of long-chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Geographic origin may influence the lipid composition of fish muscle due to differences in diet, sea surface temperature, and migratory behaviour. However, comparative data across major fishing zones remain limited for this species.

Methods: Frozen muscle samples of yellowfin tuna (n=4 per zone) were collected from three fishing zones: the Western Indian Ocean (FAO 51), the Eastern Central Atlantic (FAO 34), and the Western Central Pacific (FAO 71). Total fat content was determined by Soxhlet extraction. The lipid fraction was extracted and fatty acids were derivatized to FAMEs according to ISO 12966-2:2017. Separation and quantification were performed by gas chromatography with flame ionization detection (GC-FID) using a CP-Sil 88 capillary column, with identification against a FAME 37-component standard mix.

Results: Total fat content was low and comparable across fishing zones. Fatty acid profiles were dominated by saturated fatty acids (notably palmitic acid, C16:0) and LC-PUFAs, with DHA representing the predominant n-3 fatty acid in all groups. No substantial differences in individual fatty acid proportions or EPA and DHA content were observed across the three origins.

Conclusions: Despite originating from geographically distinct fishing zones spanning three ocean basins, yellowfin tuna muscle showed a largely consistent lipid composition, suggesting that fatty acid profiles may be relatively stable across the commercial supply of this species. These findings have implications for nutritional assessments and risk-benefit analyses based on tuna consumption, regardless of geographic provenance.