New Zealand operates one of the strictest quality assurance programmes for shellfish in the world, testing both the shellfish and the water in which it grows.
Water quality is rigorously and constantly monitored with testing carried out to specifications and standards set by the US Food and Drug Administration, European Union and NZ Food Safety Authority.
Under this stringent monitoring programme no shellfish product can be harvested from farms without confirmation that water testing during the growing cycle, rainfall monitoring and product testing has declared it as safe.
Fish need a plentiful supply of well-oxygenated and unpolluted water. A good depth of water allows adequate space between net and seabed; a good water flow ensures a constant supply of dissolved oxygen and maintains the water quality.