Paralytic shellfish toxins in Alaskan Arctic food webs during the anomalously warm ocean conditions of 2019 and estimated toxin doses to Pacific walruses and bowhead whales
Paralytic shellfish toxins in Alaskan Arctic food webs during the anomalously warm ocean conditions of 2019 and estimated toxin doses to Pacific walruses and bowhead whales
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DOI：
10.1016/j.hal.2022.102205
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发表时间：
2022-03-03
期刊：
影响因子：
6.6
通讯作者：
Siddon, Elizabeth
中科院分区：
文献类型：
--
作者：
Lefebvre, Kathi A.;Fachon, Evangeline;Siddon, Elizabeth
与气候变化相关的海洋变暖，以及北极海冰范围、持续时间和厚度的减少，增加了阿拉斯加北极地区双鞭毛藻（Alexandrium catenella）有毒繁殖的风险。这种藻类产生的神经毒素影响海洋野生动物的健康，并导致人类疾病，即麻痹性贝类中毒（PSP）。本研究报告了北极食物网样本中麻痹性贝类毒素（PST）的定量浓度，包括2019年夏季在异常温暖的海洋条件下收集的浮游植物、浮游动物、底栖蛤蜊、底栖蠕虫和远洋鱼类。在波弗特海、楚科奇海和白令海陆架近海收集的底栖蛤蜊中，在所有营养水平均检测到PSTs（蛤毒素当量，STX当量），浓度高于海产品安全监管限值（80 μ g STX当量，100 g(-1)）。最值得注意的是，在圣劳伦斯岛北部发现了有毒的底栖蛤蜊（Macoma calcarea），太平洋海象（Odobenus rosmarus）在那里觅食各种底栖物种，包括Macoma。此外，2019年3月至5月期间在圣劳伦斯岛附近采集的13只海象的粪便样本均含有可检测水平的STX，其中两只动物的粪便样本（78和72 mu g STX = 100 g(-1)）接近海鲜安全监管限值。相比之下，2019年3月至9月期间，在乌特恰维克（以前的巴罗）和卡克托维克附近的波弗特海沿海水域收获的以浮游动物为食的弓头鲸（n = 9）的粪便样本中，有64%的毒素呈阳性，而且这些水平显著低于海象（最大弓头鲸8.5 μ g STX = 100 g(-1)）。这与在区域浮游动物猎物中发现的较低浓度的PSTs一致。据估计，以蛤蜊为食的海象和以浮游动物为食的弓头鲸的最大生态相关每日毒素剂量分别为21.5和0.7 μ g STX = kg体重（-1）天（-1），这表明海象比弓头鲸有更高的PST暴露。海象的平均和最大STX剂量在以前报告的范围内，可导致人类和座头鲸生病和/或死亡，而弓头鲸的剂量远低于这些水平。这些发现引起了人们的关注，即随着海洋变暖和海冰继续减少，北极海洋哺乳动物接触PST/STX的风险和健康影响可能会增加。
Climate change-related ocean warming and reduction in Arctic sea ice extent, duration and thickness increase the risk of toxic blooms of the dinoflagellate Alexandrium catenella in the Alaskan Arctic. This algal species produces neurotoxins that impact marine wildlife health and cause the human illness known as paralytic shellfish poisoning (PSP). This study reports Paralytic Shellfish Toxin (PST) concentrations quantified in Arctic food web samples that include phytoplankton, zooplankton, benthic clams, benthic worms, and pelagic fish collected throughout summer 2019 during anomalously warm ocean conditions. PSTs (saxitoxin equivalents, STX eq.) were detected in all trophic levels with concentrations above the seafood safety regulatory limit (80 mu g STX eq. 100 g(-1)) in benthic clams collected offshore on the continental shelf in the Beaufort, Chukchi, and Bering Seas. Most notably, toxic benthic clams (Macoma calcarea) were found north of Saint Lawrence Island where Pacific walruses (Odobenus rosmarus) are known to forage for a variety of benthic species, including Macoma. Additionally, fecal samples collected from 13 walruses harvested for subsistence purposes near Saint Lawrence Island during March to May 2019, all contained detectable levels of STX, with fecal samples from two animals (78 and 72 mu g STX eq. 100 g(-1)) near the seafood safety regulatory limit. In contrast, 64% of fecal samples from zooplankton-feeding bowhead whales (n = 9) harvested between March and September 2019 in coastal waters of the Beaufort Sea near Utqiagvik (formerly Barrow) and Kaktovik were toxin-positive, and those levels were significantly lower than in walruses (max bowhead 8.5 mu g STX eq. 100 g(-1)). This was consistent with the lower concentrations of PSTs found in regional zooplankton prey. Maximum ecologically-relevant daily toxin doses to walruses feeding on clams and bowhead whales feeding on zooplankton were estimated to be 21.5 and 0.7 mu g STX eq. kg body weight(-1) day(-1), respectively, suggesting that walruses had higher PST exposures than bowhead whales. Average and maximum STX doses in walruses were in the range reported previously to cause illness and/or death in humans and humpback whales, while bowhead whale doses were well below those levels. These findings raise concerns regarding potential increases in PST/STX exposure risks and health impacts to Arctic marine mammals as ocean warming and sea ice reduction continue.