Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA, USA.
Alaska Department of Fish and Game, Arctic Marine Mammal Program, 1300 College Road, Fairbanks, AK, USA.
Harmful Algae. 2016 May;55:13-24. doi: 10.1016/j.hal.2016.01.007. Epub 2016 Feb 10.
Current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (HABs), making algal toxins a growing concern in Alaskan marine food webs. Two of the most common HAB toxins along the west coast of North America are the neurotoxins domoic acid (DA) and saxitoxin (STX). Over the last 20 years, DA toxicosis has caused significant illness and mortality in marine mammals along the west coast of the USA, but has not been reported to impact marine mammals foraging in Alaskan waters. Saxitoxin, the most potent of the paralytic shellfish poisoning toxins, has been well-documented in shellfish in the Aleutians and Gulf of Alaska for decades and associated with human illnesses and deaths due to consumption of toxic clams. There is little information regarding exposure of Alaskan marine mammals. Here, the spatial patterns and prevalence of DA and STX exposure in Alaskan marine mammals are documented in order to assess health risks to northern populations including those species that are important to the nutritional, cultural, and economic well-being of Alaskan coastal communities. In this study, 905 marine mammals from 13 species were sampled including; humpback whales, bowhead whales, beluga whales, harbor porpoises, northern fur seals, Steller sea lions, harbor seals, ringed seals, bearded seals, spotted seals, ribbon seals, Pacific walruses, and northern sea otters. Domoic acid was detected in all 13 species examined and had the greatest prevalence in bowhead whales (68%) and harbor seals (67%). Saxitoxin was detected in 10 of the 13 species, with the highest prevalence in humpback whales (50%) and bowhead whales (32%). Pacific walruses contained the highest concentrations of both STX and DA, with DA concentrations similar to those detected in California sea lions exhibiting clinical signs of DA toxicosis (seizures) off the coast of Central California, USA. Forty-six individual marine mammals contained detectable concentrations of both toxins emphasizing the potential for combined exposure risks. Additionally, fetuses from a beluga whale, a harbor porpoise and a Steller sea lion contained detectable concentrations of DA documenting maternal toxin transfer in these species. These results provide evidence that HAB toxins are present throughout Alaska waters at levels high enough to be detected in marine mammals and have the potential to impact marine mammal health in the Arctic marine environment.
目前的气候趋势导致海冰迅速减少和水温升高，这可能会扩大有害藻类大量繁殖（HAB）的有利条件的北方地理范围和持续时间，使藻类毒素成为阿拉斯加海洋食物网中日益令人关注的问题。北美的西海岸两种最常见的 HAB 毒素是神经毒素软骨藻酸（DA）和石房蛤毒素（STX）。在过去的 20 年中，DA 中毒症在美国西海岸的海洋哺乳动物中导致了大量的疾病和死亡，但据报道，这种毒素并未对在阿拉斯加水域觅食的海洋哺乳动物产生影响。STX 是麻痹性贝类毒素中毒性最强的一种，几十年来，阿留申群岛和阿拉斯加湾的贝类中都有很好的记录，并与因食用有毒贻贝而导致的人类疾病和死亡有关。关于阿拉斯加海洋哺乳动物的暴露信息很少。在这里，记录了阿拉斯加海洋哺乳动物中 DA 和 STX 暴露的空间模式和流行率，以评估包括对北方种群的健康风险，包括对阿拉斯加沿海社区的营养、文化和经济福祉很重要的物种。在这项研究中，从 13 个物种中采集了 905 只海洋哺乳动物，包括：座头鲸、弓头鲸、白鲸、港湾海豹、北方毛皮海狮、北方海狮、港海豹、环斑海豹、髯海豹、斑海豹、带纹海豹、太平洋海象和北方海獭。在所有 13 个检查的物种中都检测到了软骨藻酸，在弓头鲸（68%）和港湾海豹（67%）中最为常见。在 13 个物种中的 10 个中检测到了石房蛤毒素，在座头鲸（50%）和弓头鲸（32%）中最为常见。太平洋海象体内同时含有 STX 和 DA 的浓度最高，其 DA 浓度与美国加利福尼亚中部海岸因出现软骨藻酸中毒（癫痫发作）而被发现的加利福尼亚海狮中的 DA 浓度相似。46 只海洋哺乳动物同时含有可检测浓度的两种毒素，强调了联合暴露风险的可能性。此外，一只白鲸、一只港湾海豹和一只北方海狮的胎儿中都检测到了软骨藻酸，证明了在这些物种中存在母体毒素转移。这些结果表明，HAB 毒素存在于阿拉斯加水域的各个水域，浓度足以在海洋哺乳动物中被检测到，并有可能影响北极海洋环境中海洋哺乳动物的健康。
