Semester of Graduation

Spring 2025

Degree

Master of Science (MS)

Department

Geography and Anthropology

Document Type

Thesis

Abstract

The region of Southcentral Louisiana, particularly around Bayou Teche, thrives on its commercial and recreational fisheries. These fisheries are occasionally subject to events like extreme weather that cause sudden and unexpected losses (NOAA Fisheries, 2024a). Between 2019 and 2023, a series of extreme weather events impacted southcentral Louisiana near Bayou Teche. This series of extreme events includes Hurricane Barry (2019), Hurricane Laura (2020), Hurricane Delta (2020), Hurricane Zeta (2020), Hurricane Ida (2021), and a United States Drought Monitor (USDM) D4 drought (2023). This study analyzes the impacts of the extreme weather series on coastal fish observed species richness (SR) in the Vermilion/Teche Basin. Previous research does not address the impact of the 2019–2023 extreme weather series on fisheries in the Vermilion/Teche Basin. A climatological assessment of the extreme conditions is provided as they relate to Louisiana’s general climatology, along with a local fishery assessment. Climatological assessment results show that Hurricanes Laura and Ida were the tropical cyclones (TC)s with the strongest intensity (64 and 66.9 ms⁻¹, respectively), and Hurricane Barry was the TC that produced the third most precipitation in the Vermilion/Teche watershed (908.8 km³) out of tropical cyclones TCs from 1980 to 2023. Additionally, in 2023, the Vermilion/Teche watershed received the third-lowest precipitation from 1951 to 2023. Hydrologically, conditions at the FIMP sampling times were little affected after the TCs; however, all sites had a sustained salinity increase in 2023 well above the 75th percentile. The fisheries assessment was conducted with a before-after-control-impact (BACI) model that analyzed the fish SR before and after each extreme weather event at 7 sites. A separate BACI analysis combined the Bay Sites, the sites located north of Marsh Island, and the Gulf Sites, the sites directly interacting with the Gulf of Mexico, into groups. The Fishery assessment results show SR decreased at the Bay and Gulf Sites after Hurricane Barry (p=0.03). SR increased at the Gulf Sites after Hurricane Laura (p=0.02), and SR decreased at the Gulf Sites after Hurricane Ida (p=0.05). Site 1’s individual SR increased during the 2023 drought (p=0.04), and the collective Bay Sites experienced an SR decrease after the 2023 drought (p=0.01). Hurricane Barry likely changed SR at the Bay and Gulf Sites because its track directly passed over the Vermilion/Teche Basin. The more powerful storms changed SR at the Gulf Sites, and the Bay Sites were more vulnerable to drought.

Date

4-21-2025

Committee Chair

Jill Trepanier

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