postlarvae

Postlarvae are a developmental stage in many aquatic crustaceans, occurring after the final larval instar and before the juvenile stage. The term is most commonly used for decapods such as penaeid shrimp, crabs, and lobsters. In the standard decapod larval sequence, nauplius, protozoea, mysis, and zoea precede the postlarva, which then progresses to the juvenile form. Postlarvae are usually free-swimming and planktonic for a time before settling to a benthic habitat where growth continues.

Morphology and ecology of postlarvae vary by species but generally include a body plan that resembles the adult more closely than earlier larval stages. Postlarvae possess developed swimming appendages and a growing exoskeleton, with reproductive organs beginning to form. They feed on plankton and detritus, and their survival depends on factors such as water quality, temperature, salinity, and food availability. The duration of the postlarval stage and the timing of settlement differ among species and environments.

In aquaculture and fisheries, the postlarval stage is a critical phase for production. PLs are produced in hatcheries from nauplii or mysis and reared to designated postlarval instars (often referred to as PL1, PL2, etc.) before stocking into nurseries or grow-out ponds. Management practices emphasize optimal water quality, nutrition, and controlled stocking densities to improve survival and growth during the PL stage. Terminology and exact developmental timing can vary among species.