Good water quality must be maintained in the holding tanks by using either a flow-through system utilizing warm water (e.g., geothermal) or a heated, recirculating system with particulate and biological filtration. Water temperature in the system should be maintained between 75 and 85oF. Warmer water temperatures (80oF) and a longer photoperiod (12 to 14 hours of light) in the hatchery will increase spawning rates. Research has shown that peak spawning occurred at water temperatures of 82oF and 14 hours of light. Light intensity should be low (just enough light for hatchery person- nel to work). Dark colored tanks with partial covers can reduce stress associated with intense light and movement around the tanks. Also tanks with smooth surfaces, like fiberglass or stainless steel, minimize damage to the exoskeleton of the crayfish. Damage or abrasions of the exoskeleton can lead to disease problems.