Graduation Year

2024

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Marine Science

Major Professor

Mya Breitbart, Ph.D.

Committee Member

Christopher D. Stallings, Ph.D.

Committee Member

Glenn Zapfe, M.S.

Keywords

CUFES, dispersal, Fish reproductive ecology, Fisheries biology, Gulf of Mexico, molecular biology

Abstract

Identifying spawning areas for economically and ecologically important fishes is critical for fisheries conservation and ecosystem-based management. Additionally, monitoring the spawning dynamics of fishes is increasingly important as temperatures and oceanic conditions change. I used genetic barcoding to identify fish eggs collected across the West Florida Shelf (WFS) during September of 2013, 2014, and 2019. Fish eggs were collected on National Oceanic and Atmospheric Administration (NOAA) Southeast Area Monitoring and Assessment Program (SEAMAP) ichthyoplankton cruises using a Continuous Underway Fish Egg Sampler (CUFES). Analysis of 4,400 fish eggs from the three years resulted in the identification of 83 unique species within 36 families. A 79% DNA barcoding success rate was achieved, with 47% of all identifications being at the species level. PERMANOVA results revealed significant differences in fish egg beta-diversity across the three years sampled, four preassigned depth classes, and within pre-assigned regional strata. My findings generally aligned with known adult fish distributions and spawning patterns, and I found that water column depth played a more significant role than regional strata in structuring the fish egg community. Eggs from several economically important species were collected and observed at relatively high frequencies, including Lutjanus campechanus (red snapper), Lutjanus synagris (lane snapper), Rhomboplites aurorubens (vermillion snapper), Hyporthodus flavolimbatus (yellowedge grouper), and Scomberomorus cavalla (king mackerel). The West Florida Coastal Ocean Model was used to hindcast the trajectories of the fish eggs and predict possible spawning locations. Backward tracking over a span of 36 hours was conducted, based on the assumption that most fish eggs on the WFS undergo hatching within this time window. The model predicted egg transport distances ranging from 7-79 km (mean distance of ~21 km), with greater transport distances observed on the outer shelf in comparison to the middle and inner shelf. These results further our understanding of the spatial and interannual variation of fish spawning dynamics on the WFS and mark the beginning of a long-term monitoring effort.

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