Reproductive Dynamics of Gulf Black Sea Bass in the Northeastern Gulf of Mexico

Our knowledge of the reproductive dynamics of many economically important marine fish species is remarkably poor. This limits our ability to assess and manage the effects of exploitation on their reproductive potential. The Gulf Black Sea Bass Centropristis striata melana is a temperate serranid that contributes to both recreational and commercial fisheries in the state of Florida, however, the reproductive dynamics of this species is not well understood. To fill this gap, I conducted a fisheries-independent survey to explore the spatial and demographic scales of spawning populations in the northeastern Gulf of Mexico. To ensure effective and non-biased sampling, I assessed gear type and fish behavior sampling biases for the Gulf Black Sea Bass. Baited fish traps and hook-and-line were equally selective for fish size, however, hook-and-line had a higher catch efficiency. Body size was strongly correlated to social dominance in the Gulf Black Sea Bass, however, larger individuals in the population were not more susceptible to hook-and-line gears. These results indicated that hook-and-line was the optimal sampling method with relatively high efficiency and low sampling bias. Using hook-an-line fishery-independent surveys, I assessed the spatial and temporal dynamics of the Gulf Black Sea Bass spawning populations to test whether spawning populations were consistent across spawning habitats and describe demographic trends in spawning. Spawning populations were not consistent across available spawning habitat and displayed a high degree of spatial variability over scales of no more than 10 kilometers. These patterns were likely influenced by juvenile recruitment rates. Demography was a clear factor in the timing of reproduction as the proportion and average size of females and males significantly changed over the course of the spawning season. Larger females began spawning earlier in the spawning season and larger males were present on spawning habitats for longer periods. Overall, the findings of this study highlighted the important roles of spatial and demographic variation in the reproduction of the Gulf Black Sea Bass, and warrant future investigation due to their implications into the conservation and management of this economically important fishery.