Biology Department, Acadia University, 33 Westwood Ave., B4P 2R6, Wolfville, Nova Scotia, Canada; Departamento de Biología, Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI·MAR), Av. República Saharaui s/n, 11510, Puerto Real, Cádiz, Spain.
Biology Department, Acadia University, 33 Westwood Ave., B4P 2R6, Wolfville, Nova Scotia, Canada.
Mar Environ Res. 2020 Oct;161:105087. doi: 10.1016/j.marenvres.2020.105087. Epub 2020 Jul 25.
Feeding ecology of Atlantic bluefin tuna (ABFT, Thunnus thynnus), from the Gulf of Saint Lawrence, Canada, was assessed by stomach content and stable isotope analyses. Stomachs were collected from 161 individuals averaging 249 ± 20 cm in curved fork length and 248 ± 64 in round weight. The fish were caught by commercial fishing boats using rod and reel gear during fall 2015-2017. Liver and muscle samples were taken from 133 fish for stable isotope analysis. Atlantic mackerel (Scomber scombrus) was the most abundant prey item in 2015 (%Alimentary index, %AI = 88.94), whereas in 2016 and 2017 the ABFT diet was mainly composed of Atlantic herring (Clupea harengus) (%AI = 56.73 and %AI = 77.23, respectively). PERMANOVA analysis revealed significant differences in the dietary composition between years. δN values varied between 12.3 and 15.4‰ for muscle and between 11.1 and 14.6‰ for liver. δC values ranged from -19.9 to -16.5‰ for muscle and from -20.7 to -17.3‰ for liver. PERMANOVA analysis also detected inter-annual isotopic differences in both muscle and liver samples (p < 0.05). Daily rations (DR) were similar in 2015 and 2016 (DR = 1.02 ± 0.32 and DR = 1.10 ± 0.21, respectively), but higher in 2017 (DR = 1.73 ± 0.54).
采用胃内容物分析法和稳定同位素分析法评估了来自加拿大圣劳伦斯湾的大西洋蓝鳍金枪鱼（ABFT，Thunnus thynnus）的摄食生态。从 2015 年至 2017 年秋季，使用钓竿和卷线轮渔具，商业渔船共捕获了 161 条平均弯曲叉长 249 ± 20 厘米、圆重 248 ± 64 厘米的个体。从 133 条鱼中采集了肝脏和肌肉样本进行稳定同位素分析。2015 年，大西洋马鲛鱼（Scomber scombrus）是最丰富的食物（饮食指数，%AI 为 88.94），而在 2016 年和 2017 年，ABFT 的食物主要由大西洋鲱（Clupea harengus）组成（%AI 分别为 56.73 和 77.23）。PERMANOVA 分析表明，不同年份的饮食组成存在显著差异。肌肉的 δN 值在 12.3 和 15.4‰之间变化，肝脏的 δN 值在 11.1 和 14.6‰之间变化。肌肉的 δC 值范围为-19.9 至-16.5‰，肝脏的 δC 值范围为-20.7 至-17.3‰。PERMANOVA 分析还检测到肌肉和肝脏样本在不同年份的同位素差异（p<0.05）。2015 年和 2016 年的日食量（DR）相似（DR 分别为 1.02 ± 0.32 和 1.10 ± 0.21），但 2017 年更高（DR 为 1.73 ± 0.54）。
