1. Unit 12 Aquaculture The FOOD CHAIN in a freshwater pond WATER QUALITY Production systems © 2005 Thomson Delmar Learning. All rights reserved.

2. Aquaculture Defined The management of the Earth’s water surface to INCREASE the harvest of usable plant and animal products © 2005 Thomson Delmar Learning. All rights reserved.

3. The Aquatic Environment The salinity gradient The aquatic food chain –Sunlight. –Green plants and algae. –Plants are eaten by the fish. –Fish are eaten by larger fish and animals. © 2005 Thomson Delmar Learning. All rights reserved.

4. A Little Biology Shellfish –are aquatic animals with a shell. –include clams, mussels, oysters. Crustaceans –are aquatic organisms with EXOSKELETONS. –MOLT ( replace their outer shells as they grow ). –include saltwater lobsters, crawfish, crabs, shrimps, prawns. © 2005 Thomson Delmar Learning. All rights reserved.

5. Testing Water Quality Test for dissolved oxygen (amount of oxygen in the water). pH (the alkalinity or acidity of the water). water hardness (amount of calcium in the water). turbidity (amount of suspended matter in the water). © 2005 Thomson Delmar Learning. All rights reserved.

6. Testing Water Quality (continued) temperature. ammonia/nitrite/nitrate levels. toxins. © 2005 Thomson Delmar Learning. All rights reserved.

7. Selection of Aquaculture Crops Trout and salmonids Catfish Clams, crabs, and oysters Shrimp and prawn © 2005 Thomson Delmar Learning. All rights reserved.

8. Production Systems Open ponds, rivers, and bays—stocked with natural or cultured young Caged culture—floating-pen cages in natural waters © 2005 Thomson Delmar Learning. All rights reserved.