Interdisciplinary Seminar: Jessie Straub

iiAn interdisciplinary seminar from UNC Marine Sciences graduate student, Jessie Straub. Presented by the UNC-CH Department of Marine Sciences and UNC’s Institute of Marine Sciences (IMS). The main location of this event will be in seminar room 222 at IMS in Morehead City, NC. The seminar will be streamed live to room G201 on the ground floor of Murray Hall on UNC-CH campus in Chapel Hill, NC. This event will be held on Monday, November 5th, at 12:20pm.

Seminar Title: The Mighty Mississippi: Impacts of Freshwater Diversions on Economically Important Fisheries

Abstract: The Mississippi River delivers sediments and nutrients to coastal Louisiana, forming one of the most productive wetland systems and providing habitat for economically and ecologically important fisheries. For estuarine nekton communities, freshwater flow is one of the most influential factors affecting biotic community structure and production. Following the Mississippi River flood of 1927, the US Army Corps of Engineers initiated levee development along the Mississippi River for flood control and navigation, which has contributed to wetland loss of approximately 1,883 mi2 from 1932-2010. Restoration approaches have focused on the creation of large-scale river diversions that can be used to create artificial discharges similar to natural spring floods. Built in 1991, the Carnarvon diversion changed riverine flow and salinity patterns in the Breton Sound estuary. Following the opening of the diversion, there was a shift in nekton community structure in Breton Sound. Species of economic importance increased in biomass, and higher abundances of small fish were observed, indicating that the area serves as a refuge from large predators. The establishment of a salinity gradient allowed available habitat for species from a wide range of salinity tolerances. Decisions about future Mississippi River management need to view proposed diversions as estuary-wide connected systems, recognizing the diversions will impact sediment and nutrient delivery, and modelling how the diversions will impact spatial distribution and community structure of fisheries.