Ingestion Of Gametes By Protists - Fate Of Surplus Reproductive Energy In The Sea

GC GRANT
JE OLNEY

Abstract

Spring ichthyoplankton surveys in the tidal freshwater reaches of Virginia rivers were used to document the temporal and spatial occurrence of spawning by striped bass Morone saxatilis (Walbaum). Single river systems were intensively surveyed in 1980 (York River system), 1981 (James River system), and 1982 (Rappahannock River). In spring 1983, all three river systems were sampled at approximately weekly intervals. Some spawning occurred in all years, including those yielding poor year-classes (1980 and 1981). Spawning occurred largely within the first 40 km of tidal freshwater in major rivers, except when drought conditions displaced spawning upstream in advance of encroaching saltwater. Eggs appeared in sharp, brief peaks of abundance, usually between the third week in April and the first week in May. Peak densities coincided with rapidly rising water temperatures in the range 13.7-19.5-degrees-C.