Date of Award

4-28-2023

Document Type

Thesis

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Kristine Grayson

Second Advisor

Robert Leaf

Abstract

Within the Gulf of Mexico, forage fish species serve as an important link between lower trophic levels and higher trophic levels, supporting economically valuable predator fish, birds, and mammals. Despite the key ecological role of forage fish, fisheries management efforts are often directed elsewhere; as a result, input data for fisheries models is unavailable for many forage fish species. To fill this knowledge gap, we sought to produce species-specific caloric content values for four forage fish species in the Gulf of Mexico: Atlantic croaker (Micropogonias undulatus), white trout (Cynoscion arenarius), bay anchovy (Anchoa mitchilli), and gulf menhaden (Breevortia patronus). We additionally investigated the impacts of body length, month of collection, as well as Mississippi River discharge to determine the response of caloric content to physiological, temporal, and environmental variation. Using bomb calorimetry, we were able to determine the dry energy density of the four forage fish species. Additionally, the dry varied by month, with dry energy densities dropping during and after migration. Furthermore, the dry energy densities of gulf menhaden and Atlantic croaker were positively correlated with fork length. There was also a limited positive relationship between river discharge and dry energy density. Ultimately, our species-specific caloric content values for forage fish in the Gulf of Mexico add much needed specificity to current fisheries models, especially since our caloric content values are available for a variety of temporal, environmental, and physiological conditions.

Additional Files
2023-Walsh-form.pdf (1034 kB)
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