The larval stage of invasive Dreissena spp. mussels (i.e., veligers) are understudied despite their seasonal numerical dominance among plankton. We report the spring and summer veliger densities and size structure across the main basin, North Channel, and Georgian Bay of Lake Huron, and seek to explain spatiotemporal variation. Monthly sampling was conducted at 9 transects and up to 3 sites per transect from spring through summer 2017. Veliger densities peaked in June and July, and we found comparable densities and biomasses of veligers between basins, despite differences in density of juvenile and adult mussels across these regions. Using a generalized additive model to explain variations in veliger density, we found that temperature, chlorophyll a, and nitrates/nitrites were most important. We generated an index of veliger attrition based on size distributions that revealed a higher rate of attrition in the North Channel than the rest of the lake. A logistic model indicated a threshold calcium concentration of around 22 mg/L was necessary for veligers to survive to larger sizes and recruit to their juvenile and benthic adult life stages. Improved understanding of factors that regulate the production and survival of Dreissena veligers could improve the ability of managers to assess future invasion threats as well as explore potential control options.

侵入性Dreissena spp的幼虫阶段。尽管贻贝在浮游生物中的季节性数量占主导地位，但人们对贻贝（即蚌类）的研究不足。我们报告了休伦湖主盆地、北海峡和乔治亚湾的春季和夏季veliger 密度和尺寸结构，并试图解释时空变化。从 2017 年春季到夏季，每月在 9 个样带和每个样带最多 3 个地点进行采样。Veliger 密度在 6 月和 7 月达到峰值，我们发现流域之间的veliger 密度和生物量相当，尽管幼体和成体贻贝的密度存在差异这些地区。使用广义加性模型来解释 Veliger 密度的变化，我们发现温度、叶绿素a，硝酸盐/亚硝酸盐是最重要的。我们根据尺寸分布生成了一个veliger 磨损指数，该指数显示北海峡的磨损率高于湖的其他部分。一个逻辑模型表明，大约 22 毫克/升的阈值钙浓度对于维吉格动物生存到更大的尺寸并招募到它们的幼年和底栖成年生活阶段是必要的。更好地了解调节Dreissena veligers生产和生存的因素可以提高管理人员评估未来入侵威胁以及探索潜在控制方案的能力。