Research Article

Fatty acid allocation between muscle and gonads of Senegalese sardinellas under upwelling influence

¹ CNRS, IRD, Univ Brest, Ifremer LEMAR F-29280 Plouzané, France
² Univ Brest, Ifremer, BEEP, F-29280 Plouzané, France
³ IRD, Univ Brest, CNRS, Ifremer, LEMAR, Dakar, Sénégal
⁴ Centre de Recherche Océanographique de Dakar-Thiaroye (CRODT), Institut Sénégalais de Recherches Agricoles (ISRA), Route du Front de Terre, Dakar, Sénégal

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 23 October 2025
Accepted: 5 June 2026

Abstract

Sardinellas (Sardinella aurita and Sardinella maderensis) are small pelagic fish that play a critical ecological and socio-economic role in West African coasts. These species primarily feed on plankton, a rich source of long chain polyunsaturated fatty acids (LC-PUFAs), including docosahexaenoic acid (DHA), arachidonic acid (ARA), and eicosapentaenoic acid (EPA). This study investigated the relationship between the muscle and gonad LC-PUFA profiles and the physiological status in both males and females at two periods of the upwelling season (January and March, 2022). Fatty acid profiles were measured in storage and membrane lipids to capture environmental and physiological variations, respectively. The ARA and DHA contents were largely enriched in membrane lipids as compared to reserve lipids. Within membrane lipids, gonads contained higher levels of LC-PUFA compared to muscle, suggesting preferential allocation to gonad structures. From January to March, Le Cren body condition index increased, associated to increasing reserve lipid storage. Additionally, gonad membrane showed an increasing DHA and a decreasing ARA contents. Altogether, these results suggest increasing lipid storage and investment for reproduction for both species and sexes. However, the gonado-somatic index of females remained stable between the two sampling periods, highlighting the importance to distinguish between the dynamics of gonadal biochemical composition and their morphological growth, two processes that may be decoupled depending on the maturation stage. Inter-specific differences were, however, observed: S. maderensis exhibited higher DHA and EPA concentrations in muscle reserves, and a higher ARA content in both reserves and membranes lipids compared to S. aurita, suggesting differential dietary LC-PUFA trophic regimes between species. Overall, our findings highlight the strong coupling between environmental conditions, dietary LC-PUFA availability and reproductive physiology in sardinellas. This emphasizes the critical role of LC-PUFA in supporting their reproductive success, and thus, to sustain the management and conservation of their populations in upwelling ecosystems.