An observation of episodic feeding and growth of larval Leiostomus xanthurus in the northern Gulf of Mexico

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Abstract
Four cruises were conducted in the northern Gulf of Mexico over two spawning seasons of the sciaenid fish Leiostomus xanthurus . On only one occasion did unusually high densities of larvae and their principal microzooplanktonic foods co-occur. Peak densities of larvae and microzooplankton were observed in a thin lens of cool surface water that characterized a hydrographic discontinuity, and all larvae contained high numbers of food organisms in their guts. Instantaneous exponential growth rates estimated from measurements of otolith growth increments, indicated accelerated growth on the day that larvae were collected. A laboratory experiment verified that larval L. xanthurus responds to an increased ration with accelerated growth that is detectable on otoliths. Together these data suggest that the spatial distribution of L. xanthurus larvae and their microzooplanktonic food is patchy and that interactions of larvae and microzooplankton may be episodic.