Abstract The Susquehanna River basin is one of the largest and most diverse watersheds in the northeastern United States, however, its historically renowned Micropterus dolomieu (smallmouth bass–SMB) fishery has been in decline since the mid-2000s. Agricultural herbicide runoff has been identified as a major risk for Susquehanna basin SMB populations given their effects as endocrine disrupting compounds (EDCs). During the summers of 2016 and 2017, we assessed potential threats to SMB populations in 11 tributaries to the Juniata River, the second largest tributary to the Susquehanna River. Passive water samplers were installed for 38–39 days in ecologically important tributaries to quantify six common herbicides, and SMB were collected from nine sites in 2016 and 2017 to assess their health and morphology. Our passive water samplers showed markedly higher EDC concentrations than has previously been documented in the Juniata basin, with atrazine occurring at all sites and in the highest concentrations (11.09–91.02 ng/L). SMB blood samples revealed complete prevalence (100%) of vitellogenin, an egg protein precursor, in male fishes further confirming previous rates male vitellogenisis. Additionally, SMB hepatosomatic index (HSI) was statistically higher in female SMB than in male SMB (P < 0.001), and higher than many previous regional SMB studies further highlighting a contaminant-based stressor. Finally, a geometric morphometric analysis of SMB body shape indicated morphologies to be significantly site-based. Morphological differences were in line with the ram-suction feeding continuum, further revealing potential vulnerability in SMB sub-populations where EDCs may alter food web dynamics and prey availability. Overall, our study of the Juniata River Basin highlights high EDC concentrations alongside high rates of male vitellogenisis and elevated HSI, and proposes novel theory for morphological vulnerability in SMB sub-populations.

中文翻译：

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美国宾夕法尼亚州朱尼亚塔河流域的小口黑鲈（Micropterus dolomieu）面临的潜在威胁

摘要 萨斯奎哈纳河流域是美国东北部最大和最多样化的流域之一，然而，其历史上著名的小嘴鲈鱼（小嘴鲈鱼 - SMB）渔业自 2000 年代中期以来一直在下降。鉴于其作为内分泌干扰化合物 (EDC) 的影响，农业除草剂径流已被确定为萨斯奎哈纳盆地 SMB 种群的主要风险。在 2016 年和 2017 年的夏天，我们评估了萨斯奎哈纳河的第二大支流朱尼亚塔河的 11 条支流中 SMB 种群的潜在威胁。在生态重要的支流中安装被动水采样器 38-39 天，以量化六种常见的除草剂，并于 2016 年和 2017 年从九个地点收集 SMB，以评估它们的健康和形态。我们的被动水采样器显示出明显高于 Juniata 盆地先前记录的 EDC 浓度，阿特拉津出现在所有地点，浓度最高 (11.09–91.02 ng/L)。SMB 血液样本显示，卵蛋白前体卵黄蛋白在雄性鱼类中完全流行 (100%)，进一步证实了以前的雄性卵黄生成率。此外，女性 SMB 的 SMB 肝体指数 (HSI) 在统计学上高于男性 SMB（P < 0.001），并且高于许多先前的区域 SMB 研究，进一步突出了基于污染物的压力源。最后，SMB 身体形状的几何形态测量分析表明形态学显着基于站点。形态差异符合冲压吸饲连续体，进一步揭示 SMB 亚群的潜在脆弱性，其中 EDC 可能改变食物网动态和猎物可用性。总体而言，我们对 Juniata 河流域的研究突出了高 EDC 浓度以及高雄性卵黄生成率和 HSI 升高，并提出了 SMB 亚群形态脆弱性的新理论。