Early Life History of Red Drum ('Sciaenops ocellatus') in the Northcentral Gulf of Mexico

摘要

Ichthyoplankton and zooplankton samples were collected in the near vicinity of a subsurface current drogue during fourteen, 24 hour cruises in late summer and fall months, 1983-85, in east Louisiana, Mississippi, and Alabama coastal and shelf waters. Peak red drum spawning in these waters occurred from early September through early October when water temperatures over the shelf were decreasing rapidly from 27-29 C in early September to 24-25 C in early October 1984 and 1985. A diel pattern in vertical distribution was evident with red drum larvae and their planktonic prey being generally more abundant higher in the water column during daylight hours and deeper at night. Larval growth, estimated by correlating age with standard length and dry weight measurements, was positively associated with water temperature. Trophic ontogeny of red drum larvae was determined by comparing the gut contents of 553 larvae with available prey in the contiguous water column. Red drum larvae from each size class selected particular prey types from within the prey size range that the larvae were capable of ingesting.