If you want to try to catch them, a couple tips I've observed by watching my pair. The eggs will be green for most of the time, they'll turn more white one day, the next day they should be all white, and that night after lights out the larvae hatch and are released. I think its about a 2 week period from spawning to hatch-release. Keep an eye on them the first night you notice they're white, you may have missed the slight transition color change and they may release that night. Another giveaway is the eggs will appear 'looser' under the shrimp's tail the night of release, not all compact like they are when green. Depending on your light schedule, it may be an hour or two before the larvae are released so patience is required, lol.
I looked at them under my microscope, they're sooo cool way up close! I need to see if I can get a couple pics and post them.