Abstract The imperiled pallid sturgeon (Scaphirhynchus albus) and closely related, but more common, shovelnose sturgeon (S. platorynchus) are believed to broadcast adhesive, demersal eggs in the current and over coarse substrate in turbid rivers of the North American midcontinent. It has been hypothesized that eggs settle immediately following fertilization, but field conditions preclude direct observation. We conducted laboratory studies to characterize the diameter, shape, settling velocity, and specific gravity of pallid sturgeon and shovelnose sturgeon eggs. Based on these laboratory measurements, we then modeled the potential fate of pallid sturgeon eggs by considering these physical properties in the context of two field sites where spawning has occurred. Although eggs of pallid sturgeon and shovelnose sturgeon were of a similar size and shape, shovelnose sturgeon eggs had slightly higher specific gravity and settling velocity. For representative hydraulic conditions at documented spawning sites in the mainstem Missouri and Lower Yellowstone Rivers, eggs of both species will likely be concentrated near the bed although some eggs may be distributed throughout the water column. Simulations of egg transport indicate that eggs may be transported up to several hundred meters downstream from spawning locations in the approximate length of time required for eggs to become adhesive. Estimates of egg transport presented here rely on simplifying assumptions about river hydraulics and limited understanding of how eggs interact with the complex substrates and flow near the bed; results highlight the need for additional studies to evaluate the fate of eggs and fertilized embryos of both species.

中文翻译：

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苍白鲟和鲟鱼卵的物理特性及模拟运输

摘要 濒临灭绝的苍白鲟 (Scaphirhynchus albus) 和密切相关但更常见的铲鼻鲟 (S. platorynchus) 被认为在北美大陆中部浑浊的河流中的当前和粗糙基质上散播粘性的底层卵。已经假设受精后卵会立即沉降，但现场条件排除了直接观察。我们进行了实验室研究，以表征苍白鲟和鲟鱼卵的直径、形状、沉降速度和比重。根据这些实验室测量结果，我们通过在两个产卵现场的背景下考虑这些物理特性来模拟苍白鲟鱼卵的潜在命运。虽然苍白鲟和鲟鱼卵的大小和形状相似，但鲟鱼卵的比重和沉降速度略高。对于密苏里河和黄石河下游主要产卵地点的代表性水力条件，这两种物种的卵可能会集中在河床附近，尽管一些卵可能分布在整个水体中。卵运输的模拟表明，在卵变得粘连所需的大约时间长度内，卵可能被运输到产卵地点下游数百米。此处介绍的鸡蛋运输估计依赖于简化关于河流水力学的假设，以及对鸡蛋如何与复杂基质相互作用并在河床附近流动的有限理解；