It's my understanding from the game biologists here that it's 48 hours of free floating in moving water to hatch the eggs. That would be different lengths of river for every system because of grade and volume affecting current I would think. Here they have about 27 or 28 miles on one river and a little more on the other and both rivers produce every year. The too we're in the piedmont and both rivers are tail waters so the COE and the VGDIF work together to regulate water flow for the stripers to be able to swim up to a point where they have enough free run river to support hatching the roe.
When we catch them in April on the way up they're just squirting eggs, looks like they're about to pop.
<(((>< In tribute to Ben, Duck Hunter extraordinaire, and man's best friend.