Influence of Natural and Anthropogenic Environmental Variability on Larval Fish Diet, Growth, and Condition in the Northcentral Gulf of Mexico

<p>The northern Gulf of Mexico experiences high levels of freshwater runoff annually from various sources including the Mississippi River and Mobile Bay, among other sources. Early life history stages of fishes are especially vulnerable to environmental variability created by freshwater discharge. The objectives of this study were to describe the available prey field, diet, growth and condition of larval fishes with respect to various effects of freshwater discharge in the northern Gulf. The first chapter compared these parameters in larval Gulf Menhaden (<em>Brevoortia patronus</em>) collected from three different water masses characterized by physical and biological parameters after the opening of the Bonnet Carré Spillway in January 2016. Zooplankton community structure was found to be significantly different among the water masses. Larval Gulf Menhaden diet did not differ significantly among the water masses, but larvae from the Chandeleur Sound region had significantly lower recent growth and poorer condition than larvae from the other regions. The second chapter addressed the same parameters in Atlantic Bumper (<em>Chloroscombrus chrysurus</em>) in relation to summer-time hypoxia. Although found in a reduced habitat, the larvae collected above hypoxia did not experience differences in prey field, diet, growth, or condition based on morphometric analyses. Overall, my studies exemplify how difficult it is to predict results of environmental variability on larval fishes.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2018

Author dc:creator

• Hoover, Angie

Contributors dc:contributor

• Frank Hernandez
• Robert Griffitt
• Alison Deary

• larval fish
• gulf of mexico
• gulf menhaden
• atlantic bumper
• freshwater-discharge
• hypoxia
• Other Environmental Sciences
• Other Oceanography and Atmospheric Sciences and Meteorology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/583

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1449