Publications

Cherubin et al. 2011


scientific article | Ecol Model | open access Open access small aa108fa7f478951c693af64a05bc4b46e6711dbb69a20809512a129d4d6b870f

Flow and transport characteristics at an Epinephelus guttatus (red hind grouper) spawning aggregation site in St. Thomas (US Virgin Islands)

Cherubin LM, Nemeth RS, Idrisi N

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Abstract

This study characterizes the flow field at a spawning site located at the shelf break of a Caribbean island for the Epinephelus guttatus (red hind grouper) in relation to this species spawning events. In order to understand the oceanographic dynamics targeted by the fishes, current measurements were profiled throughout the water column for almost a year at the spawning site. The characteristics of the flow field and its evolution after spawning were investigated by using a numerical ocean model that resolved the observed tide and simulated the island scale flow where passive, neutrally buoyant virtual particles were released for 10 days to trace the flow pathways. Observed currents during the spawning period revealed that the flow was vertically sheared, to the south and weakest at the bottom, and to the west or east at the surface. The tidal analysis revealed that the flow at the time of spawning was directed across and on-shelf, although weaker close to the bottom. The model showed that the initial on-shelf transport was counteracted by the bottom flow directed to the shelf break, where virtual particles were entrained by the downwelling flow. A significant percent of particles resided less than two hundred meters deep, in the vicinity of the chlorophyll maximum and returned to the shelf break, close to the release location within 8-10 days. This journey was largely controlled by the timing between downwelling at the spawning site and upwelling further east at the shelf break, which was driven by the coupling between wind and tide induced vertical movements at the shelf break and deeper. The release location, vertical rotation of its flow field, and its transport properties were shown to be relatively resilient to the passage of transient sub-mesoscale eddies as well as to acute mesoscale flow reversals, suggesting that physical retention is maximized in the area surrounding the spawning site.

Research sites

10.1016   j.ecolmodel.2011.05.031
Keywords
Meta-data
Depth range
0- 41 m

Mesophotic “mentions”
0 x (total of 8991 words)

Fields
Ecology Oceanography Long-term monitoring

Research focus
Fishes

Locations
US Virgin Islands

Research platforms
Diving - Regular Open-Circuit
Author profiles
Richard Nemeth ( 15 pubs)