A crab probably bite the grub in half.
If I were you I would try the waters underneath I55 between LaPlace and Ruddock. Use a cork and a 1/32 oz. jig head with a tube jig or solid body jig of your liking. Fish about 12” to 36”.
The crappie are moving in to spawn. So cypress trees, logs, cypress knees will do good, or any type of shallow water structure.
You can use this on any type of water around your area. There is also Bayou Segnette, they have oilfield canals that should be good about now. Hope this may help