S

  • Salinity: The concentration of dissolved salts in water (measured in ppt or ‰).

  • Sanitary Fallow (Dry-out): The period when the pond remains dry, clean, and disinfected (no water, no animals) between cycles, to break the disease cycle.

  • Secchi Disk: A simple device used to measure water transparency (turbidity), indicating plankton density.

  • Sediment: The layer of accumulated organic and inorganic material at the bottom of a pond.

  • Semi-intensive: A culture system with moderate densities, use of feed, and some aeration, still partially dependent on natural productivity.

  • Settling Pond: A structure used in effluent treatment to remove suspended solids by gravity.

  • Sex Reversal: The technique (usually hormonal) used in tilapia hatchery to produce all-male populations.

  • Siphon (Siphoning): The action of removing accumulated sludge from the bottom of a tank or pond using gravity.

  • Size (or Grade): A category used to sell shrimp, usually expressed as the number of pieces (shrimp) per pound (lb) or kilogram (kg).

  • Sludge: The accumulation of organic matter (feces, uneaten feed, dead plankton) at the bottom of the pond, which consumes oxygen and releases ammonia.

  • Sodium Bicarbonate: A compound used to quickly raise the alkalinity of the water without significantly impacting pH.

  • Solids (Total, Suspended, Settleable): Measures of the organic and inorganic matter in the water. Excess suspended solids can affect gills and light penetration.

  • Specific Growth Rate (SGR): A formula (based on logarithms) that measures the percentage growth per day.

  • SPF (Specific Pathogen Free): Animals (usually PLs or broodstock) that are "Free of Specific Pathogens," certified by lab analysis.

  • SPR (Specific Pathogen Resistant): Animals genetically selected to be "Resistant to Specific Pathogens."

  • Stocking: The act of introducing post-larvae or fingerlings into the pond to begin the culture cycle.

  • Stocking Density: The number (or weight) of animals per unit of area or volume (e.g., 10 PLs/m² or 5 fish/m³).

  • Stress: The physiological response of an animal to adverse conditions (e.g., low DO, handling), which reduces growth and immunity.

  • Streptococcus: A genus of bacteria that causes severe disease (Streptococcosis) in fish, especially tilapia.

  • Super-intensive: A system with very high densities, fully dependent on technology (aeration, RAS, BFT) and feed.

  • Survival Rate: The percentage of animals that survive from stocking to harvest.

  • Sustainability: The practice of production that balances economic viability, social responsibility, and environmental protection.

  • Symbiotic: A product that combines probiotics (good bacteria) and prebiotics (food for the good bacteria).