Minnows and grass shrimp are here year round. No place for them to realy go. Cold months they will find protected water with little current.
They are very sluggish in cold water and a running tide would just sweep them away. As the water warms they will start to move out into the small todal creeks where they will spend the warm months feeding and reproducing.
Cast netting is kind of thin during the spring. The fish we are after like mullet and peanut bunker won't be in numbers until late summer. You can try for herring but that is just as difficult. They are fast swimmers and when the nets hit the water they are already gone.
Try fishing for the herring with a sibiki rig at night around Stone Harbor. You can have a lot of fun and catch a great supply of strip baits for flounder. They tend to show up sometime in March and will hang around through April if we are lucky.
Big schools show around docks just as it's getting dark. They seem to be feeding on baby herring a few inches long. They force the schools of bait up against docks and bulkheads and cut into them. By throwing a sibiki rig you can have a blast with multiple hookups. The are great fighters and jump all over the place.
Good luck and have fun.