Baker John W, Suffoletta Drew T, Lewis Jessica N, Pamperin Kailey M, Giordano Rachel M, Madrigal Theresa, Solangi Moby
Institute for Marine Mammal Studies, Gulfport, MS, USA.
Institute for Marine Mammal Studies, Gulfport, MS, USA.
Sci Total Environ. 2025 Jan 1;958:177977. doi: 10.1016/j.scitotenv.2024.177977. Epub 2024 Dec 18.
In the last decade, the frequency of the use of the Bonnet Carré Spillway (BCS) to divert water from the Mississippi River by the United States Army Corps of Engineers (USACE) has dramatically increased. The BCS is designed to protect the city of New Orleans, Louisiana from levee breaches and devastating floods. In 2011 and 2019, during extreme flood events, the USACE diverted 6.4 trillion gallons and 10.07 trillion gallons of Mississippi River water into Lake Borgne and Biloxi Marsh, Louisiana, and the Mississippi Sound, Mississippi. The 2011 and 2019 diversions and lower-discharge diversions in other years have coincided with high freshwater discharges of coastal Mississippi streams, the appearance of common bottlenose dolphins (Tursiops truncatus, dolphins) with skin lesions, and large numbers of stranded dolphins. To determine what might be causing dolphin skin lesions and strandings, we investigated BCS and coastal stream discharges between 2010 and 2021 as possible drivers. Generalized additive, kriging, and seasonal-trend decomposition using loess models showed that the prevalence of skin lesions in the western Mississippi Sound and Biloxi Marsh was significantly related to BCS discharge and not to stream discharge. From 2010 to 2021, the frequency of stranded dolphins across the Mississippi Sound was significantly related to BCS discharges, while coastal stream discharges had localized effects. Between 2018 and 2019, the relationship between the frequency of dolphin strandings and BCS discharge was highly significant. In this model, the relationship between dolphin strandings and stream discharge was not significant. This research provides evidence that freshwater diversions through the BCS likely increase the prevalence of skin lesions on live dolphins, strandings, and mortality in the Mississippi Sound.
在过去十年中，美国陆军工程兵团（USACE）使用邦尼特卡里溢洪道（BCS）从密西西比河引水的频率大幅增加。BCS旨在保护路易斯安那州新奥尔良市免受堤坝决口和毁灭性洪水的影响。2011年和2019年，在极端洪水事件期间，USACE分别将6.4万亿加仑和10.07万亿加仑的密西西比河河水引入路易斯安那州的博尔赫内湖和比洛克西沼泽以及密西西比州的密西西比海峡。2011年和2019年的分流以及其他年份的低流量分流与密西西比州沿海溪流的高淡水流量、出现皮肤病变的普通宽吻海豚（Tursiops truncatus，海豚）以及大量搁浅的海豚同时发生。为了确定可能导致海豚皮肤病变和搁浅的原因，我们调查了2010年至2021年期间的BCS和沿海溪流流量，将其作为可能的驱动因素。广义相加模型、克里金法和使用黄土模型的季节性趋势分解表明，密西西比海峡西部和比洛克西沼泽中皮肤病变的患病率与BCS流量显著相关，而与溪流流量无关。2010年至2021年期间，密西西比海峡各地搁浅海豚的频率与BCS流量显著相关，而沿海溪流流量具有局部影响。2018年至2019年期间，海豚搁浅频率与BCS流量之间的关系非常显著。在该模型中，海豚搁浅与溪流流量之间的关系不显著。这项研究提供了证据，表明通过BCS进行的淡水改道可能会增加密西西比海峡中活海豚的皮肤病变患病率、搁浅率和死亡率。
