Cascadia Research Collective, 218½ W. 4th Avenue, Olympia, WA 98501, USA.
Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Association, 2725 Montlake Boulevard East, Seattle, WA 98112, USA.
Sci Total Environ. 2020 Sep 1;733:138880. doi: 10.1016/j.scitotenv.2020.138880. Epub 2020 May 4.
False killer whales are long-lived, slow to mature, apex predators, and therefore susceptible to bioaccumulation of persistent organic pollutants (POPs). Hawaiian waters are home to three distinct populations: pelagic; Northwestern Hawaiian Islands (NWHI) insular; and main Hawaiian Islands (MHI) insular. Following a precipitous decline over recent decades, the MHI population was listed as "endangered" under the Endangered Species Act in 2012. This study assesses the risk of POP exposure to these populations by examining pollutant concentrations and ratios from blubber samples (n = 56) related to life history characteristics and MHI social clusters. Samples were analyzed for PCBs, DDTs, PBDEs, and some organochlorine pesticides. Skin samples (n = 52) were analyzed for stable isotopes δC and δN to gain insight into MHI false killer whale foraging ecology. Pollutant levels were similar among populations, although MHI whales had a significantly higher mean ratio of DDTs/PCBs than NWHI whales. The ∑PCB concentrations of 28 MHI individuals (68%) sampled were equal to or greater than suggested thresholds for deleterious health effects in marine mammals. The highest POP values among our samples were found in four stranded MHI animals. Eight of 24 MHI adult females have not been documented to have given birth; whether they have yet to reproduce, are reproductive senescent, or are experiencing reproductive dysfunction related to high POP exposure is unknown. Juvenile/sub-adults had significantly higher concentrations of certain contaminants than those measured in adults, and may be at greater risk of negative health effects during development. Multivariate analyses, POP ratios, and stable isotope ratios indicate varying risk of POP exposure, foraging locations and potentially prey items among MHI social clusters. Our findings provide invaluable insight into the ongoing risk POPs pose to the MHI population's viability, as well as consideration of risk for the NWHI and pelagic stocks.
伪虎鲸寿命长、成熟缓慢、处于食物链顶端，因此容易受到持久性有机污染物（POPs）的生物蓄积影响。夏威夷水域栖息着三个不同的种群：远洋种群；西北夏威夷群岛（NWHI）岛屿种群；和主夏威夷群岛（MHI）岛屿种群。在过去几十年中，MHI 种群数量急剧下降，2012 年根据《濒危物种法》被列为“濒危”物种。本研究通过检查与生活史特征和 MHI 社会群体相关的鲸脂样本（n=56）中的污染物浓度和比值，评估这些种群接触 POP 的风险。样本分析了 PCBs、DDTs、PBDEs 和一些有机氯农药。对 52 个皮肤样本（n=52）进行了稳定同位素 δC 和 δN 的分析，以深入了解 MHI 伪虎鲸的觅食生态。尽管 MHI 鲸鱼的 DDT/PCBs 比值明显高于 NWHI 鲸鱼，但三个种群的污染物水平相似。在所采集的 28 头 MHI 个体中（占 68%），有 28 头个体的∑PCB 浓度等于或高于海洋哺乳动物产生有害健康影响的建议阈值。我们样本中最高的 POP 值出现在四只搁浅的 MHI 动物身上。24 头 MHI 成年雌鲸中，有 8 头尚未有生育记录；它们是否尚未繁殖、生殖衰老，还是由于 POP 暴露过高而导致生殖功能障碍，目前尚不清楚。幼年/亚成年个体的某些污染物浓度明显高于成年个体，在发育过程中可能面临更大的健康负面影响风险。多变量分析、POP 比值和稳定同位素比值表明，MHI 社会群体之间存在不同的 POP 暴露风险、觅食地点和潜在的猎物。我们的研究结果为 POP 对 MHI 种群生存能力构成的持续风险以及对 NWHI 和远洋种群的风险提供了宝贵的见解。
