We use a long handled wire screen net & lantern hanging over the side of the boat, and ease along the deep rocky shoreline at night & scoop them up. They will follow along with the light (& I've even had them follow along under my blacklights, too), but there's usually only a few big enough to use for every 25-50yds of bank you cover.
We see them in our lakes, jumping out of the water after small gnats or skipping across the water when fleeing a predator fish ... and so they've gotten the nickname of "skipjacks" more so than being called "ghost minnows". I've even heard them called "pin minnows", and I'm sure they have many other erroneous nicknames in other parts of the country.

Around here ... a three year old Crappie will be 8-11" long, depending on which lake they live in, and are capable of spawning by the age of three, regardless of length. Those fish in your picture are Black Crappie & the three darker colored ones would be the males ... and with the water temps being in the low 50's, I suspect they're just "getting ready" to start moving in to spawn. From your description of the trip, I'd say they were on a pre-spawn feeding pattern ... which should only get better as the water temps approach the upper 50deg range. When it starts to push the 60deg mark, they should be on the beds & serious about spawning.

... luck2ya, my friend


... cp