I have thought of having a small pond for shiners seperated by a dam for the large pond. Then have a pipe from one pond to the next that is above the large pond water lever. Then every fall pump water from the large pond into the small until the the water level rises enough to create water flow through the pipe into the big pond. Then sein thousands of shiners towards the pipe in the samll pond so they go though the pipe into the big pond.
I would still have enough left over to spawn again next year creating a few more thousand every year.