Surface drifter movement indicates onshore egg transport from a reef fish spawning aggregation
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© 2015 Taylor & Francis. Most commercially, important food fishes in the tropics reproduce in spawning aggregations, which serve to replenish their populations via larval dispersal. Dispersal pathways are not well understood. This study examines the dispersal hypothesis assumed for most dispersal modeling studies, i.e. that prevailing currents transport freshly released eggs offshore and away from spawning sites, where they are advected into far-field ocean currents and contribute to long-distance larval transport. We used GPS-tracked surface drifters, quantitative ichthyoplankton tows, and microsatellite DNA markers to assess egg dispersal pathways from a well-documented Lutjanus cyanopterus spawning aggregation site. We conducted and plotted 95 drifter tracks over a bathymetric map of the study area and used geoprocessing techniques to determine the direction, speed, and variability of these tracks. Our field-collected data do not support the hypothesis that surface currents transport Cubera snapper gametes offshore during peak spawning. Eggs were transported onshore toward the barrier reef and potentially through the channel, supporting the idea that local retention may be more important than long-distance transport. These results are highly relevant for parameterizing larval connectivity models. Furthermore, we demonstrate the use of a low-cost and easily replicable method to track currents and egg dispersal from spawning aggregation sites.
author list (cited authors)
Méndez-Jiménez, A., Heyman, W. D., & DiMarco, S. F.