Identifier

etd-03242014-125642

Degree

Doctor of Philosophy (PhD)

Department

Renewable Natural Resources

Document Type

Dissertation

Abstract

Gulf killifish, Fundulus grandis, shows promise for commercial development as a marine baitfish species. Significant markets for F. grandis already exist throughout the Gulf Coast, with the vast majority of supply coming from wild-harvests, which can be hampered by seasonal availability and inconsistent fish health and size. The genus Fundulus also represents an important group of model vertebrates for biological study. A recent review paper described this genus as the premier teleost model for environmental biology. New information generated as a result of the work contained in this dissertation may be more broadly applicable to sister species of F. grandis, enhancing the primary goal of improving reproductive output and fitness in cultured individuals of this species. Results of this dissertation include optimization of culture salinity, female broodfish body size, and dietary lipid composition. Optimal salinity for culture of juvenile F. grandis was 12.0‰, with growth incrementally increasing between 0.5, 5.0, 8.0, and 12.0‰. Survival was negatively affected at 0.5‰. Optimal body size for female broodfish was 12-13 g. Minimum size recommended for broodfish was 7 g and per-unit-mass fecundity begins to level off in females greater than 13 g. Fecundity of F. grandis was less sensitive to manipulations of dietary lipid content than many other fishes. No difference in fecundity was found among fish fed isonitrogenous diets ranging in lipid content from 4.0 to 13.8%. Excess lipid was mostly stored in the intraperitoneal cavity, rather than being partitioned for reproduction. Dietary lipid composition produced very little effect on overall fecundity in F. grandis, despite experimental diets with very different fatty acid (FA) composition. Differences did occur in subsequent larvae at extreme physiological conditions, but these variations were unlikely to have any effect on survival in culture or natural settings. Examinations of FA dynamics across time revealed that F. grandis likely utilizes a combination of mobilization from somatic reserves and de novo biosynthesis of long chain polyunsaturated FAs to compensate for dietary FA deficiency. Overall, the characteristic physiological plasticity of F. grandis also applied to lipid dynamics.

Date

2014

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Green, Christopher

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