Date of Award

Fall 2019

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

School

Ocean Science and Engineering

Committee Chair

Dr. Chester Rakocinski

Committee Chair School

Ocean Science and Engineering

Committee Member 2

Dr. Frank Hernandez

Committee Member 2 School

Ocean Science and Engineering

Committee Member 3

Dr. Eric Powell

Committee Member 3 School

Ocean Science and Engineering

Abstract

The eastern oyster (C. virginica) is a foundation species that improves water quality, protects shorelines, provides refuge for other organisms, and contributes to commercial fisheries. Successful early recruitment of eastern oyster is vital for resupplying adult populations in the face of habitat loss. Coastal oyster populations are challenged by freshwater input, hypoxia, predation and overfishing. Consequently, substantial efforts have been dedicated toward oyster restoration within the northern Gulf of Mexico. The overall objective of this study was to consider the role and importance of early recruitment to oyster restoration in western Mississippi Sound. During the summer 2018 recruitment period, we quantified larval oyster supply and spat settlement at eight sites varying in region (inshore vs offshore) and background substrate (restored limestone, restored relic shell, historically unrestored substrates). Larvae were quantified relative to life cycle stage in addition to region, sampling month, and restoration status. Settlement metrics included abundance of early and late size classes, spat area cover, maximum individual size, geometric mean size, barnacle area cover, and spat scar abundance, and were compared relative to variation in background substrate, tile surface, predator exclusion treatment, region, and month. Larval densities varied among sites and increased throughout the summer. D-stage densities were highest in September, and veliger densities were higher in the second half of the sampling season. Spat settlement aligned with patterns of larval density, and was higher in more protected refuge treatments. This study illustrates how recruitment studies can assist with management decisions related to restoring this critical habitat.

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