Grass shrimp definately.The tide must be moving more important than time of the day.Keeping them alive is a little tricky.The regulars use wood
"cars" like minnow keepers.i just take a large cooler,put ice packs on the bottom and cover with moist newspaper.Spread the shrimp out on this.Anchor with two hooks if possible.Start
throwing 5 or six shrimp out at a time to get slick going.Don't stop chumming til your done
fishing. You have to keep it going.