Habitat relationships for alewife and blueback herring spawning in a Virginia stream

We examined associations between habitat variables and occurrence and densi ty of alewife Alosa pseudoharengus) and blueback herring (Alosa aestivalis) early egg stages (unfertilized and newly fertilized) in a tributary of the Rappahannock River, Virginia from February to May 1992. We looked for temp oral associations between tidal condition, time of day, light intensity, an d temperature and peaks in egg densities. Occurrences of alewife early egg stages were positively related to dissolved oxygen (7-12 mg/l) and velocity (3-20 cm/s), and peak densities were positively associated with peaks in w ater temperature (within the range of 4-19 degrees C). Occurrences of blueb ack herring early egg stages were positively related to water temperature ( 14-22 degrees C). There was no correlation between occurrences of early egg s of either species and tidal condition.