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Distribution, Growth, and Transport of Larval Fishes and Implications for Population Dynamics

Christina Hern√°ndez, Ph.D., 2021
Joel Llopiz, Advisor

The early life stages of marine fishes play a critical role in population dynamics. This dissertation demonstrates the value of combining larval observations with model simulations. In Chapter 2, field observations of ontogenetic vertical distributions of coral reef fish revealed a diversity of behaviors. In Caribbean-wide particle-tracking simulations, surface-dwelling larvae experienced greater connectivity, while the evenly-distributed and ontogenetic vertical migration behaviors led to greater retention. Chapter 3 presents evidence of tuna spawning inside a large no-take marine protected area, the Phoenix Islands Protected Area (PIPA). In all 3 study years, the distributions of larval tuna (Katsuwonus pelamis and Thunnus spp.) were similar and estimated spawning sites were located inside PIPA. Chapter 4 examines the abundance, growth, and transport of Atlantic bluefin tuna larvae collected in the Slope Sea. Age and growth analyses of bluefin tuna larvae collected in the Slope Sea and the Gulf of Mexico in 2016 did not show a growth rate difference between regions, but did suggest that Slope Sea larvae are larger at the onset of exogenous feeding. Larvae backtracked to spawning locations north of Cape Hatteras. This thesis presents valuable contributions to the study of larval fishes and the attendant implications for marine resource management.