Bluefin Tuna Resources Department, National Research Institute of Far Seas Fisheries, Japan Fisheries Research and Education Agency, Shizuoka-shi, Shizuoka, Japan.
Environmental Management Unit, JAPAN NUS Co. Ltd, Shinjuku-ku, Tokyo, Japan.
PLoS One. 2019 Sep 25;14(9):e0222824. doi: 10.1371/journal.pone.0222824. eCollection 2019.
Lipid and fatty acid composition of female Pacific bluefin tuna (PBF, Thunnus orientalis) reproductive and somatic tissues in southwestern North Pacific and Sea of Japan spawning grounds are compared. Total lipid (TL) levels are higher in liver than white muscle tissues. An increased gonadosomatic index (GSI) during the early spawning season coincided with decreased TL. Levels of triacylglycerols (TAG) in PBF liver tissues from the Nansei Islands and Sea of Japan, and white muscle in fishes from the Sea of Japan, decreased during the spawning season, while TAG in ovary tissues did not. Concurrent reductions in TL and increases in GSI early in the spawning season suggest TAG depletion was caused by allocation from liver and white muscle tissues to oocytes, that the liver is one of the important lipid-storage organs in PBF, and this species mostly reliant on capital deposits as a mixed capital-income breeder. Differences of docosahexaenoic acid (DHA) levels between spawning grounds were lower in ovary than in muscle and liver tissues. However, eicosapentaenoic (EPA) and arachidonic acid (ARA) levels that influence egg development and embryo and larval growth are significantly higher in PBF tissues from the Sea of Japan than Nansei Islands, which coincided with larval quality. These suggest a maternal effect exists, with egg quality influencing offspring survival, and that the reproductive strategy of PBF varies according to local variation at each spawning ground.
比较了西南北太平洋和日本海产卵场雌性太平洋蓝鳍金枪鱼（PBF，Thunnus orientalis）生殖组织和躯体组织的脂质和脂肪酸组成。肝脏中的总脂质（TL）水平高于白色肌肉组织。在早期产卵季节，性腺体指数（GSI）增加，同时 TL 降低。来自南海诸岛和日本海的 PBF 肝脏组织以及来自日本海的白色肌肉组织中的三酰基甘油（TAG）水平在产卵季节下降，而卵巢组织中的 TAG 没有下降。在产卵季节早期，TL 降低和 GSI 增加表明 TAG 耗竭是由于肝脏和白色肌肉组织向卵母细胞的分配引起的，肝脏是 PBF 重要的脂质储存器官之一，该物种主要依赖资本存款作为混合资本收益繁殖者。产卵场之间 DHA 水平的差异在卵巢中低于肌肉和肝脏组织。然而，影响卵子发育和胚胎和幼虫生长的二十碳五烯酸（EPA）和花生四烯酸（ARA）水平在日本海的 PBF 组织中明显高于南海诸岛，这与幼虫质量相符。这表明存在母体效应，卵子质量影响后代存活率，并且 PBF 的繁殖策略根据每个产卵场的局部变化而有所不同。
