Lipid and fatty acid dynamics in mature female albacore tuna (Thunnus alalunga) in the western Indian Ocean

Abstract

Lipid composition in the reproductive and somatic tissues were investigated for female albacore tuna, Thunnus alalunga, in the western Indian Ocean, between latitude 18–21°S and longitude 56–60°E, from January 2014 to March 2015. Highest total lipids (TL) were found in the gonads of spawning-capable females (SCP) (mainly phospholipids, PL, triacylglycerols, TAG and wax esters, WE) and in the liver of females in the late regressing and regenerating ovary phases (mainly TAG, PL and sterols, ST). Muscle TL was low but exhibited high inter-individual variability. Correlations between gonadosomatic and hepatosomatic indices with TL and the lipid classes in albacore gonads and liver describes a pattern of reallocation of energy from the liver to the gonads during SCP. Female albacore were also observed to pursue foraging activities even during this period. Therefore, female albacore can be considered as a capital-income breeder relying mostly on stored lipids before the onset of reproduction and to a lesser extent on energy derived from concurrent feeding during the spawning season. Overall, the three examined tissues had similar general fatty acid profiles with the dominance of 22:6ω3 (docosahexaenoic acid, DHA), 16:0, 18:0 and 18:1ω9. The proportions of fatty acids varied with maturity stage and ovary lobe, with the smaller lobe having significantly higher proportions of essential fatty acids, as well as 16:0 and 18:1n9, compared to the larger one. Our results provide new information on the life-history and energy allocation strategy of albacore which will assist fisheries managers.

Lipid and fatty acid dynamics by maternal Pacific bluefin tuna

“…These lipoproteins are synthesised by the liver, which in the majority of teleost fish then transports most yolk proteins to the developing oocyte [12, 39]. Variation in TL levels in ovary tissues of female PBF in different oocyte developmental stages (Fig 2) is comparable to that reported for other tunas [21, 40–42], being high in Ly and Mn (developing or spawning capable phase), and low in Pn (resting or regressing phase) and Hy (spawning capable phase). Although we did not statistically test for variation in lipid classes, variation in TL might indicate preferential accumulation of certain lipids from the reserves of other tissues during vitellogenesis.…”

“…Therefore, the distribution of lipid classes in somatic and gonad tissues during the reproductive cycle is indicative of the reproductive strategy a species follows [21, 41, 42, 49]. Many species, including yellowfin tuna and albacore, present with a mixture of capital- and income-breeding strategies [21, 40, 47].…”

“…Limited information is available on the feeding habits of PBF during spawning season [50]. Therefore, PBF may depend largely on capital to finance reproductive output, and we propose it to be a mixed capital-income breeder, like albacore [40].…”

Stable isotope analysis indicates resource partitioning and trophic niche overlap in larvae of four tuna species in the Gulf of Mexico

“…The use of CSI-A AA , particularly for calculating TP, highlighted how this effect can lead to apparent, yet inaccurate, trophic differences in the early life of tunas when comparing only SIA bulk values. Lipid composition analysis and lipid reserves utilization has also revealed a capital breeding strategy in the congeneric albacore tuna T. alalunga from the Indian Ocean (Dhurmeea et al 2018). Highest total lipids were found in the liver of albacore pre-spawners, which suggested they rely mostly on stored lipids for energy associated with reproduction (Dhurmeea et al 2018).…”

Unlocking the intraspecific aquaculture potential from the wild biodiversity to facilitate aquaculture development

“…Talbi et al 2011; Bigarré et al 2017), as well as a check‐up of the quality of breeders (e.g. lipid content in oocytes; Dhurmeea et al 2018). Unfortunately, some of such tests are still unavailable (e.g.…”