The efficient and profitable production of fish, crustaceans, and other aquatic organisms in aquaculture depends on a suitable environment in which they can reproduce and grow. Because those organisms live in water, the major environ mental concern within the culture system is water quality. Water supplies for aquaculture systems may naturally be oflow quality or polluted by human activity, but in most instances, the primary reason for water quality impairment is the culture activity itself. Manures, fertilizers, and feeds applied to ponds to enhance production only can be partially converted to animal biomass. Thus, at moderate and high production levels, the inputs of nutrients and organic matter to culture units may exceed the assimilative capacity of the ecosystems. The result is deteriorating water quality which stresses the culture species, and stress leads to poor growth, greater incidence of disease, increased mortality, and low produc tion. Effluents from aquaculture systems can cause pollution of receiving waters, and pollution entering ponds in source water or chemicals added to ponds for management purposes can contaminate aquacultural products. Thus, water quality in aquaculture extends into the arenas of environmental protection and food quality and safety. A considerable body of literature on water quality management in aquaculture has been accumulated over the past 50 years. The first attempt to compile this information was a small book entitled Water Quality in Warmwater Fish Ponds (Boyd I 979a).

Zusammenfassung
Because those organisms live in water, the major environ mental concern within the culture system is water quality. Water supplies for aquaculture systems may naturally be oflow quality or polluted by human activity, but in most instances, the primary reason for water quality impairment is the culture activity itself.

Inhalt

1. Water Quality and Aquaculture: Preliminary considerations.- 1.1. Introduction.- 1.2. The Role of Pond Aquaculture.- 1.3. Water Quality Restraints.- 1.4. Water Quality Management.- 1.5. Water Quality Measurement.- 1.6. Prospectus.- 3. Water Quality Requirements.- 2.1. Introduction.- 2.2. Food Webs and Aquaculture Production.- 2.3. Aquaculture Production in Pond Culture Systems.- 2.4. Phytoplankton Communities.- 2.5. Carbon in Aquaculture Ponds.- 2.6. Nitrogen in Aquaculture Ponds.- 2.7. Phosphorus in Aquaculture Ponds.- 2.8. Fate of Nutrients and Organic Matter.- 2.9. Dissolved Oxygen in Aquaculture Ponds.- 3. Water Quality Requirements.- 3.1. Introduction.- 3.2. Aquatic Toxicology.- 3.3. Water Temperature.- 3.4. Salinity.- 3.5. pH.- 3.6. Total Alkalinity.- 3.7. Total Hardness and Calcium.- 3.8. Dissolved Oxygen.- 3.9. Carbon Dioxide.- 3.10. Dissolved Gas Supersaturation.- 3.11. Ammonia.- 3.12. Nitrite.- 3.13. Nitrate.- 3.14. Hydrogen Sulfide.- 3.15. Copper and Other Heavy Metals.- 3.16. Chlorine.- 3.17. Turbidity.- 4. Water Use.- 4.1. Introduction.- 4.2. Types of Ponds.- 4.3. Water Budgets.- 4.4. Water Requirement for Aquaculture.- 4.5. Water Exchange.- 4.6. Water Conservation Techniques.- 5. Liming.- 5.1. Introduction.- 5.2. Liming Materials.- 5.3. Effects on Water Quality and Fish Production.- 5.4. Identification of Ponds Needing Lime.- 5.5. Soil Characteristics and Liming.- 5.6. Lime Requirement.- 5.7. Liming Practices.- 5.8. Acid Rain.- 6. Fertilization.- 6.1. Introduction.- 6.2. Chemical Fertilizers.- 6.3. Manures.- 6.4. Principles of Pond Fertilization.- 6.5. Review of Fertilization Trials.- 6.6. The Practice of Pond Fertilization.- 7. Aeration.- 7.1. Introduction.- 7.2. Aeration and Production.- 7.3. Mechanical Aerators.- 7.4. Gravity Aeration.- 7.5. Aerator Performance.- 7.6. Improved Design for Paddle-Wheel Aerators.- 7.7. Practical Considerations.- 7.8. Predicting Dissolved Oxygen Concentrations.- 8. Water Circulation.- 8.1. Introduction.- 8.2. Temperature and Stratification.- 8.3. Devices for Circulating Pond Water.- 8.4. Measurement of Water Circulation.- 8.5. Effects of Water Circulation.- 9. Turbidity and Appearance of Water.- 9.1. Introduction.- 9.2. Measurements of the Appearance of Water.- 9.3. Enhancing Turbidity.- 9.4. Sources of Turbidity.- 9.5. Sedimentation in Ponds.- 9.6. Settling Basins and Erosion Control.- 9.7. Turbidity Removal from Pond Waters.- 10. Aquatic Weed Control.- 10.1. Introduction.- 10.2. Common Aquatic Weeds.- 10.3. The Occurrence of Weed Problems.- 10.4. Management of Aquatic Weed Problems.- 10.5. General Pond Management Practices.- 10.6. Biological Control.- 10.7. Chemical Control.- 10.8. Control of Phytoplankton Blooms.- 11. Off-Flavors and Harmful Algae.- 11.1. Introduction.- 11.2. Off-Flavors.- 11.3. Harmful Algae.- 12. Pollution.- 12.1. Introduction.- 12.2. Toxicity Tests.- 12.3. Types of Pollution.- 12.4. Toxicity Investigations.- 12.5. Protection from Pollution.- 13. Chemical, Physical, and Biological Treatments.- 13.1. Introduction.- 13.2. Oxidants.- 13.3. Piscicides.- 13.4. Toxic Metabolites and pH.- 13.5. Therapeutants.- 13.6. Probiotics.- 13.7. Bactericides.- 13.8. Miscellaneous Treatments.- 13.9. Registration of Chemicals.- 13.10. Application of Chemicals to Ponds.- 14. Waste Management.- 14.1. Introduction.- 14.2. Source of Nutrients and Organic Matter.- 14.3. Fate of Nutrients and Organic Matter.- 14.4. Sources of Suspended Solids.- 14.5. Volume of Effluents.- 14.6. Composition of Pond Effluents.- 14.7. Water Quality Improvement through Pond Management.- 14.8. Effluent Treatment.- 14.9. Environmental Effects.- 14.10. Solid Wastes.- 14.11. Effluent Regulations.- 14.12. Best Management Practices.- 15. Measurement of Water Quality.- 15.1. Introduction.- 15.2. Variability of Water Quality.- 15.3. Types of Water Assessment Programs.- 15.4. Guidelines for Sampling Programs.- 15.5. Water Samplers and Sample Storage.- 15.6. Water Analysis Kits and Portable Meters.- 15.7. Data Analysis and Records.- 16. Sustainability and Environmental Issues.- 16.1. Introduction.- 16.2. Environmental Concerns.- 16.3. Food Safety Considerations.- 16.4. Social Concerns.- 16.5. Sustainability.- 16.6. Environmental Impact Assessment.- 16.7. Impact Mitigation.- 16.8. Rehabilitation.- 16.9. Demonstration and Education.- 16.10. Industry Efforts.- References.