Harmful algal bloom (HAB) toxins have severe negative impacts on marine mammals, particularly for Florida bottlenose dolphins (Tursiops truncatus) which frequently experience mass mortality events. Dolphins on the Florida Atlantic coast inhabit a region endemic to two HAB species, Karenia brevis and Pyrodinium bahamense, which produce the neurotoxins brevetoxin (PbTx) and saxitoxin (STX), respectively. Although toxic HABs and associated dolphin mortality events have been reported from this region, there is a lack of available data necessary for comparing toxin exposure levels between bloom ('exposed') conditions and non-bloom ('baseline') conditions. Here we present a 10-year dataset of PbTx and STX concentrations detected in dolphins stranding in this region, and compare the toxin loads from HAB-exposed dolphins to those detected in dolphins recovered in the absence of a HAB. We analyzed liver tissue samples from dead-stranded dolphins (n = 119) recovered and necropsied between 2002-2011, using an enzyme-linked immunosorbent assay (ELISA) modified for use with mammalian tissues. For dolphins recovered during baseline conditions, toxin-positive samples ranged in concentration from 0.27 to 1.2 ng/g for PbTx and from 0.41 to 1.9 ng/g for STX. For K. brevis-exposed dolphins, concentrations of up to 12.1 ng PbTx/g were detected, and for P. bahamense-exposed dolphins, concentrations of up to 9.9 ng STX/g were detected. Baseline PbTx values were similar to those reported in other regions where K. brevis blooms are more frequent and severe, but HAB-exposed PbTx values were considerably lower relative to these other regions. Since no baseline STX dolphin data exist for any region, our data serve as a first step towards establishing reference STX values for potential dolphin mortality events associated with STX-producing blooms in the future. This study demonstrates that although HABs in eastern Florida are only infrequently associated with dolphin mortalities, the presence of toxins in these animals may pose significant health risks in this region.

中文翻译：

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2002-2011年印度河泻湖宽吻海豚体内开花期间和开花间短毒素和虎毒素的比较。

有害藻华（HAB）毒素对海洋哺乳动物具有严重的负面影响，特别是对于经常经历大规模死亡事件的佛罗里达宽吻海豚（Tursiops truncatus）。佛罗里达大西洋沿岸的海豚栖息于两个HAB特有的区域，即短小克雷伯氏菌（Karenia brevis）和巴哈热霉（Pyrodinium bahamense），它们分别产生神经毒素短毒素（PbTx）和毒毒素（STX）。尽管已从该地区报告了有毒的HAB和相关的海豚死亡事件，但仍缺乏必要的可用数据来比较开花（“暴露”）条件和非开花（“基线”）条件下的毒素暴露水平。在这里，我们提供了在该区域的海豚链中检测到的PbTx和STX浓度的10年数据集，并比较暴露于HAB的海豚的毒素负荷与在没有HAB的情况下回收的海豚中检测到的毒素负荷。我们使用经修饰用于哺乳动物组织的酶联免疫吸附测定（ELISA）分析了2002-2011年间从死链海豚（n = 119）中回收并尸检的死链海豚的肝组织样本。对于在基线条件下回收的海豚，毒素阳性样品的PbTx浓度范围为0.27至1.2 ng / g，STX浓度范围为0.41至1.9 ng / g。对于暴露于短杆菌的海豚，检测到的浓度高达12.1 ng PbTx / g；对于暴露于巴哈姆森的海豚，检测到的浓度高达9.9 ng STX / g。基线PbTx值与其他地区报告的相似，其中短小K.blovis绽放更为频繁和严重，但是HAB暴露的PbTx值相对于其他区域要低得多。由于在任何地区都没有基准STX海豚数据，因此我们的数据是朝着建立与将来产生STX大花相关的潜在海豚死亡事件的参考STX值迈出的第一步。这项研究表明，尽管佛罗里达州东部的HAB很少与海豚死亡相关，但这些动物体内毒素的存在可能对该地区造成重大的健康风险。