When size matters: The gonads of larger female yellowfin tuna (Thunnus albacares) have different fatty acid profiles compared to smaller individuals

How the size of female yellowfin tuna (Thunnus albacares)affects their spawning capability and fecundity is stillan open and unresolved question due to the difficulties in investigating these complex effects in highly migratorypelagic marinefish species. However, this information is key to understanding the reproductive potential andresilience of the stock. We investigate how energetic resources are allocated for reproduction by female yel-lowfin tuna according to their size in the Gulf of Guinea (central-eastern Atlantic Ocean). Our results reveal thatlarger females have not only larger ovaries by virtue of their greater abdominal cavity, but also different fattyacid profiles in the gonads compared to smaller females, with potential effects on their spawning and recruit-ment patterns. This study contributes to the knowledge of size-dependent variation in female yellowfin tuna andpaves the way for future studies on size-dependent effects on reproductive parameters in this species.