The Mississippi River is host to multiple species of invasive carp, including bighead, silver, and black carp, which have been linked to negative ecological impacts upon introduction to a waterbody. Most of the rivers emptying into the Gulf of Mexico are hydrologically separated from the Mississippi River by seawater and have historically been considered safe from an invasion of carp attempting to traverse coastal waters due to their intolerance of seawater salinity levels. However, there is growing concern that freshwater diversions of the Mississippi River into brackish or saltwater systems could reduce salinity to a level that allows entrained carp to navigate freshwater plumes to uninvaded rivers. To help quantify this risk, we conducted an Arrival Assessment that estimates the number of invasive carp that will enter a receiving waterbody through a single freshwater diversion event. A case study using the Bonnet Carré Spillway is presented here to illustrate how water managers and spillway operators can derive predictions for a specific spillway and how mitigative steps can be taken to target the most influential parameters and help reduce the number of carp that pass. The findings of this case study suggest that, for an average spillway opening event, the number of invasive carp that pass through the Bonnet Carré Spillway is higher than many water managers may be willing to accept. This Arrival Assessment serves as the first of three components within a broader, forthcoming quantitative risk assessment that will also consider the number of carp that survive (Survival Assessment) to reach a suitable, uninvaded river for reproduction and population sustainment (Establishment Assessment) and determine the magnitude and uncertainty of the risk of introduction to uninvaded waters downstream from a freshwater diversion that forms a hydrological connection to a source waterbody inhabited by invasive carp.

中文翻译：

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量化通过淡水改道引入入侵鲤鱼的概率：到达评估

密西西比河是多种入侵鲤鱼的栖息地，包括鳙鱼、鲢鱼和青鱼，这些鲤鱼引入水体后会对生态产生负面影响。大多数注入墨西哥湾的河流在水文上与密西西比河被海水隔开，历史上一直被认为不会受到试图穿越沿海水域的鲤鱼的入侵，因为它们无法忍受海水盐度水平。然而，人们越来越担心，密西西比河的淡水改道进入咸水或咸水系统可能会将盐度降低到允许夹带的鲤鱼通过淡水羽流到达未入侵河流的水平。为了帮助量化这种风险，我们进行了到达评估，估计通过一次淡水改道事件进入接收水体的入侵鲤鱼的数量。本文介绍了使用 Bonnet Carré 溢洪道的案例研究，以说明水管理者和溢洪道运营商如何得出特定溢洪道的预测，以及如何采取缓解措施来针对最有影响力的参数并帮助减少通过的鲤鱼数量。本案例研究的结果表明，对于平均溢洪道开放事件，通过 Bonnet Carré 溢洪道的入侵鲤鱼数量高于许多水管理者可能愿意接受的数量。该到达评估是即将进行的更广泛的定量风险评估中三个组成部分中的第一个，该评估还将考虑存活下来的鲤鱼数量（生存评估）以到达合适的、未入侵的河流进行繁殖和种群维持（建立评估）并确定与入侵鲤鱼栖息的水源水体形成水文联系的淡水引道下游未入侵水域引入风险的大小和不确定性。