How much longer until the shad spawn should be in full swing? If memory serves me right I think 2nd to 3rd week of May?
Of course, there are some differences in timing with respect to location, water body and weather, but generally speaking....
Gizzard shad, as mentioned above, tend to spawn once a year in the spring. The other common shad, Threadfin (these are closely related both belonging to the Genus, Dorosoma
) tends to spawn continuously throughout the warmer part of the year with peak periods in the spring and again in the late summer. The early spawn being temperature, daylight length and climate related, the late peak period being more related to the maturation of the young of the year, spring spawned, shad. once started the Threadfin spawn will continue, at a reduced rate every night into morning, all summer long.
It is the spring peak spawning period when the shad are most noticeable as they seek the sunlight warmed shallows with newly flooded vegetation for egg laying. The spawn becoming so frenzied at times that some of the shad flop out of the water and die. The later spawns happen in deeper, cooler waters as surface waters become too hot and are not as noticeable.
Newly hatched gizzard and threadfin shad are perfectly timed to coincide with the need for the earlier hatched bass fry to make the important transition from planktivore to piscivore (zooplankton based diet to fish based diet).
So...on almost any given summer night, a large, live gizzard shad on an 8/0 hook by a drop off.....ain't no tellin'.