Crustacean Culture: Shrimp and Crab Basics
Objective. Students will describe the production cycle of at least one commercially cultured penaeid shrimp species from nauplii through post-larval stocking, and identify the critical husbandry parameters for each stage.
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Crustacean Culture: Shrimp and Crab Basics
Commercial shrimp farming is one of the most economically significant sectors of global aquaculture. In the United States, Pacific white shrimp (Litopenaeus vannamei) is the dominant penaeid species raised in intensive indoor systems, biofloc technology (BFT) tanks, and outdoor ponds. Understanding the full production cycle — from fertilized egg through market-size animal — is essential for any aquaculture technician working in shrimp or broader crustacean culture.
The Penaeid Life Cycle
Penaeid shrimp pass through several distinct larval stages before reaching juvenile and market size. Each stage has specific environmental and nutritional requirements that must be managed carefully.
Nauplii hatch from fertilized eggs and are the first free-swimming stage. They are very small, do not yet feed on external food, and rely on yolk reserves. Optimal salinity at this stage is typically in the range of 28–34 ppt and temperature around 28–30 °C. Water quality must be pristine because nauplii are extremely sensitive to ammonia and pathogens.
Zoea (three sub-stages: Z1, Z2, Z3) begin active filter-feeding. Microalgae — most commonly Chaetoceros and Skeletonema species — are the primary food source. Zoea require similar salinity (28–32 ppt) and temperature (28–30 °C), with dissolved oxygen (DO) kept above 5 mg/L.
Mysis (three sub-stages) are predatory and begin to resemble miniature shrimp. Artemia nauplii (newly hatched brine shrimp) are introduced as live prey alongside continued algae dosing. Mysis are susceptible to bacterial infections; biosecurity and UV-treated water supply are critical.
Post-larvae (PL) are fully formed juvenile shrimp. Salinity can begin gradual reduction if animals are destined for low-salinity grow-out. Post-larvae are the stage stocked into ponds or grow-out systems. PL stage is numbered by days post-metamorphosis (e.g., PL-10 means ten days after reaching post-larval form). Feed transitions to formulated micro-diets or fine pellets.
Juveniles and market-size adults grow in ponds, raceways, or tank systems. Temperature is maintained between 23–30 °C and salinity is matched to system type — outdoor coastal ponds may be 15–25 ppt while inland BFT systems often operate at lower salinities of 1–15 ppt.
The Role of Algae and Artemia
Live microalgae provide not only nutrition but also water-quality conditioning in larval rearing tanks. Algae consume carbon dioxide and produce oxygen, stabilizing the culture environment. Hatcheries maintain stock cultures of selected algae species and scale up to production volumes on a daily schedule aligned with larval feeding demand.
Artemia nauplii are hatched from cysts and fed to mysis and early post-larvae. Enrichment protocols — soaking Artemia in fatty-acid emulsions — improve their nutritional profile for shrimp. Artemia management requires attention to cyst quality, hatching salinity (approximately 35 ppt), temperature (28 °C), and light, all of which affect hatch rates.
Grow-Out Systems: Extensive Pond vs. Biofloc Technology
Extensive and semi-intensive open ponds rely on natural productivity (phytoplankton, zooplankton) supplemented with formulated feed. Stocking densities are lower, water exchange rates are higher, and the environmental footprint in terms of land and water use is significant. Advantages include lower capital cost and simpler management. Risks include weather events, predators, disease introduction through water intake, and limited climate suitability in temperate regions.
Biofloc Technology (BFT) systems maintain microbial floc — aggregates of bacteria, microalgae, protozoa, and organic matter — suspended in the water column. The floc provides supplemental nutrition to shrimp and immobilizes ammonia through microbial assimilation, allowing minimal or zero water exchange. This dramatically reduces disease risk from incoming water and lowers feed conversion ratios. BFT systems require close monitoring of total suspended solids (TSS), alkalinity, carbon-to-nitrogen ratio, and DO. Aeration is non-negotiable: power failure rapidly crashes DO and can cause catastrophic mortality.
Critical Husbandry Parameters Summary
| Stage | Temperature (°C) | Salinity (ppt) | Primary Feed |
|---|---|---|---|
| Nauplii | 28–30 | 28–34 | Endogenous yolk |
| Zoea | 28–30 | 28–32 | Microalgae |
| Mysis | 28–30 | 28–32 | Algae + Artemia nauplii |
| Post-larvae | 27–30 | 15–32 | Micro-diets, Artemia |
| Juvenile/Market | 23–30 | 1–25 (system-dependent) | Formulated pellets |
Safety Considerations
Larval rearing facilities use high-pressure air blowers, UV sterilizers, and chemical disinfectants such as chlorine and formalin. Always wear appropriate PPE — nitrile gloves and splash goggles — when handling disinfectants. Electrical panels near water require GFCI protection; follow lockout/tagout (LOTO) procedures before servicing pumps or aerators. Compressed gas cylinders (CO₂ for algae, oxygen for transport) must be secured upright and used in ventilated areas. Slippery wet floors are a constant hazard; non-slip footwear and clearly marked walkways reduce fall risk.
Key terms10
Materials: SRAC fact sheets on shrimp culture, Artemia and microalgae culture references, whiteboard, projector, comparison worksheet template.
Check: Stage-parameter table and comparison worksheet reviewed; table must include correct salinity, temperature, and feed type for at least four life stages; worksheet must list at least three accurate contrasts; pass = both criteria met.
Practice check8
Answer each question, then check it. Nothing is recorded; this is your own practice.
