N

  • Nauplius: The first larval stage of shrimp after hatching (does not feed). Also used for Artemia.

  • Necrosis: Tissue death (e.g., hepatopancreas necrosis in AHPND, or muscle necrosis in IMNV).

  • Nitrate (NO₃⁻): The final (less toxic) form of nitrogen in the nitrification cycle, which can be absorbed by phytoplankton.

  • Nitrification: A two-step aerobic biological process, carried out by bacteria, that transforms toxic ammonia into toxic nitrite, and then into less toxic nitrate.

  • Nitrite (NO₂⁻): An intermediate compound of nitrification, highly toxic (prevents oxygen transport in the blood, causing "brown blood disease").

  • Nursery: An initial culture phase (intermediate between hatchery and grow-out) in smaller, controlled tanks, aiming for higher survival and control.

  • Nutraceutical: A feed additive that combines nutrition and a health benefit (e.g., immunostimulants, prebiotics).

  • Nutrient: A substance that provides nourishment essential for growth and life (e.g., protein, phosphorus, vitamins).