Abstract

There is virtually nothing known about the fate of fish larvae born on spawning aggregations from the time of spawning to settlement, yet the location of the aggregation site must be important in determining their fate. While aggregations always form in the same place and at the same time in part to assure a large number of adults will congregate for spawning, oceanographic patterns of dispersal and retention of the larvae may provide a driving force for the selection of specific spawning locations. During the winters of 2008 and 2009 we deployed Surface Velocity Profile drifters at the Nassau grouper spawning aggregation site on Little Cayman Island, BWI. A single drifter was deployed each night, then recovered 12 hours later in order to determine trajectory paths off the aggregation. In contrast to the path taken on nights prior to spawning, in both years the drifters released on the night of peak spawning showed substantial eddy formation near the aggregation site. This repeated pattern suggests an oceanographic-based “importance of place” for the aggregation site that may result in local recruitment. This would mean that local aggregations of fish are directly responsible for the long-term survival of local populations. This gives substantial credence to the need to identify and protect specific locations because they are unique and critical to the long-term survival of the many species that aggregate there.

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