Date of Award

Spring 5-2021

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)


Ocean Science and Engineering

Committee Chair

Frank Hernandez

Committee Chair School

Ocean Science and Engineering

Committee Member 2

Kevin Dillon

Committee Member 2 School

Ocean Science and Engineering

Committee Member 3

Verena Wang

Committee Member 3 School

Ocean Science and Engineering


The deep-pelagic environment encompasses ocean waters below 200 m depth, and comprises 90% of the volume of the Gulf of Mexico. Deep-pelagic fishes are important prey for many oceanic consumers, but relatively little is known about their early life history, including larval fish trophic ecology. An understanding of the role deep-pelagic fish larvae have in oceanic food webs is important in the development of ecosystem models that examine the connectivity (via vertical migrations) between the deep-pelagic and epipelagic environments with respect to trophic interactions, nutrient cycling, and carbon sequestration. In this study, archived plankton samples collected during 2010 and 2011 were used to describe the trophic ecology of the dominant deep-pelagic fish larvae collected in the northern Gulf of Mexico. Bulk-tissue stable isotope analysis of δ13C and δ 15N were performed on larvae from four different families: Myctophidae (Lanternfishes), Gonostomatidae (Bristlemouths), Sternoptychidae (Hatchetfishes) and Phosichthyidae (Lightfishes). Gut contents were counted and identified to provide taxon-specific diet information. In addition, compound-specific stable isotope analysis of amino acids of nitrogen was performed on a subset of samples from the Family Paralepididae (Barracudinas) to elucidate ontogenetic shifts in diet.