The blacktip shark (Carcharhinus limbatus) is a placental shark that uses coastal nursery areas in the Galapagos Marine Reserve, where juveniles live during their early life stages. To better understand the feeding behavior of early juvenile blacktip sharks, we conducted stable isotope analysis on 57 samples from three coastal nurseries around the archipelago. We evaluated the intraspecific variation in trophic shifts of four size classes (<60, 60–69, 70–79 and ≥ 80 cm TL) based on δ¹³C and δ¹⁵N signatures. No significant differences in δ¹³C and δ¹⁵N values were observed among nursery areas (P = 0.127 and P = 0.736, respectively) nor between sexes (P = 0.881 and P = 0.993, respectively). However, there were significant differences among size classes, with δ¹³C and δ¹⁵N values showing a negative relationship with size (R = −0.54, P = 0.001 and R = −0.60, P = 0.001, respectively). Neonates (TL < 60 cm) exhibited a larger trophic niche, whereas larger individuals (TL ≥ 80 cm) exhibited a reduction in trophic niche as a result of different use of resources. Clustered δ¹⁵N signatures for the two largest size classes showed similar feeding patterns and same trophic level, while δ¹³C signatures in all size classes showed the use of several primary carbon sources. Our results showed trophic variations among early life stages, as a result of maternal reminiscence in neonates and foraging variation in larger size classes across coastal nursery areas. This is baseline information on the feeding behavior of early juvenile blacktip sharks in the Tropical Eastern Pacific.

黑鳍鲨（Carcharhinus limbatus）是一种胎盘鲨，使用加拉帕戈斯海洋保护区的沿海苗圃地区，少年在其早期阶段生活。为了更好地了解早期黑鳍鲨的摄食行为，我们对来自群岛周围三个沿海苗圃的57个样品进行了稳定的同位素分析。我们评估了在基于δ4大小类（<60，60-69，70-79和≥80厘米TL）的营养位移的种内变异¹³ C和δ ^15个Ñ签名。在δ无显著差异¹³ C和δ ¹⁵育苗区（其中观察到的N个值P  = 0.127和P  = 0.736，分别地）也不两性之间（P  = 0.881和P  = 0.993）。然而，有大小类之间显著差异，δ ¹³ C和δ ¹⁵的N值示出具有尺寸的负相关（[R  = -0.54，P  = 0.001和- [R  = -0.60，P  = 0.001）。新生儿（TL <60厘米）表现出较大的营养生态位，而较大的个体（TL≥80 cm）则表现为不同资源利用的营养价值减少。群集δ ^15个Ñ签名两个最大尺寸类别显示类似的喂养方式和相同的营养水平，而δ ¹³所有尺寸类别的C签名均表明使用了几种主要的碳源。我们的研究结果表明，由于母亲对新生儿的怀念和沿海保育区较大规模种的觅食变化，生命早期阶段的营养变化。这是热带东太平洋早期黑鳍鲨的摄食行为的基准信息。