Brown shrimp postlarva are larger, up to about one half inch. The walking and swimming legs have developed and the postlarval looks like a miniature shrimp. The second postlarval stage rides the flood tides into the estuaries, apparently becoming active on the flood tide, and settling to the bottom during ebb tides. These postlarval ultimately settle in the upper parts of tidal creeks. Juvenile Postlarval Shrimp develop directly into juvenile shrimp.
Growth is rapid up to two and a half inches per month.
Juveniles typically stay in the marsh creeks until reaching about four to four and a half inches before moving into deeper rivers. These shrimp continue to grow but at a slower rate than Juveniles. Sub-Adults do not show any signs of ovarian maturity. Adults Adults may be five to eight inches in length. Adults are usually found in the ocean but in dry years may delay migration until cold weather occurs.