Centro para el Estudio de Sistemas Marinos (CESIMAR), CCT CENPAT, CONICET, Boulevard Brown 2915, U9120ACV Puerto Madryn, Chubut, Argentina.
Centro para el Estudio de Sistemas Marinos (CESIMAR), CCT CENPAT, CONICET, Boulevard Brown 2915, U9120ACV Puerto Madryn, Chubut, Argentina; Universidad Nacional de la Patagonia, San Juan Bosco, Boulevard Brown 3150, U9120ACV Puerto Madryn, Chubut, Argentina.
Harmful Algae. 2017 Sep;68:248-257. doi: 10.1016/j.hal.2017.09.001. Epub 2017 Sep 14.
The gulfs that surround Península Valdés (PV), Golfo Nuevo and Golfo San José in Argentina, are important calving grounds for the southern right whale Eubalaena australis. However, high calf mortality events in recent years could be associated with phycotoxin exposure. The present study evaluated the transfer of domoic acid (DA) from Pseudo-nitzschia spp., potential producers of DA, to living and dead right whales via zooplanktonic vectors, while the whales are on their calving ground at PV. Phytoplankton and mesozooplankton (primary prey of the right whales at PV and potential grazers of Pseudo-nitzschia cells) were collected during the 2015 whale season and analyzed for species composition and abundance. DA was measured in plankton and fecal whale samples (collected during whale seasons 2013, 2014 and 2015) using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The genus Pseudo-nitzschia was present in both gulfs with abundances ranging from 4.4×10 and 4.56×10 cell l. Pseudo-nitzschia australis had the highest abundance with up to 4.56×10 cell l. DA in phytoplankton was generally low, with the exception of samples collected during a P. australis bloom. No clear correlation was found between DA in phytoplankton and mesozooplankton samples. The predominance of copepods in mesozooplankton samples indicates that they were the primary vector for the transfer of DA from Pseudo-nitzschia spp. to higher trophic levels. High levels of DA were detected in four whale fecal samples (ranging from 0.30 to 710μgg dry weight of fecal sample or from 0.05 and 113.6μgg wet weight assuming a mean water content of 84%). The maximum level of DA detected in fecal samples (710μg DA g dry weight of fecal sample) is the highest reported in southern right whales to date. The current findings demonstrate for the first time that southern right whales, E. australis, are exposed to DA via copepods as vectors during their calving season in the gulfs of PV.
瓦尔迪兹半岛（PV）、新湾和圣何塞湾环绕的海域是南露脊鲸 Eubalaena australis 的重要产犊地。然而，近年来幼鲸死亡率高的事件可能与藻毒素暴露有关。本研究评估了在 PV 产犊地期间，通过浮游动物等 zooplanktonic 载体，从拟菱形藻属（潜在的 DA 生产者）向活的和死的右鲸转移软骨藻酸（DA），同时还评估了浮游植物和中型浮游动物（PV 处右鲸的主要猎物和潜在的拟菱形藻细胞捕食者）的物种组成和丰度。在 2015 年的鲸鱼季节收集浮游植物和中浮游动物（在 2013、2014 和 2015 年的鲸鱼季节收集）并进行分析，以测量物种组成和丰度。使用液相色谱-串联质谱（LC-MS/MS）在浮游生物和粪便鲸鱼样本中测量 DA。两个海湾都存在拟菱形藻属，丰度范围为 4.4×10 和 4.56×10 个细胞 l。拟菱形藻属丰度最高，达 4.56×10 个细胞 l。浮游植物中的 DA 通常较低，除了在拟菱形藻属 bloom 期间采集的样本。在浮游植物和中型浮游动物样本中没有发现 DA 之间存在明显的相关性。在中型浮游动物样本中，桡足类的优势表明它们是 DA 从拟菱形藻属向更高营养级转移的主要载体。在四个鲸鱼粪便样本中检测到高水平的 DA（范围从 0.30 到 710μgg 粪便干重，或假设平均含水量为 84%，则为 0.05 和 113.6μgg 湿重）。在粪便样本中检测到的 DA 最高水平（710μg DA g 粪便干重）是迄今为止在南露脊鲸中报告的最高水平。目前的研究结果首次表明，在 PV 湾的产犊季节，南露脊鲸 E. australis 通过桡足类作为载体接触 DA。
