2. PROGRAM OVERVIEW Class visit 1: Introduction and biology of oysters Excursion 1: Tour of local estuary and oyster processing facility Class visit 2: Oyster production Excursion 2: The business of oyster farming Class Visit 3: Improving operations Excursion 3: Harvesting and marketing

3. Today..... The importance of aquaculture Various cultivation methods used to farm oysters The oyster growing process

4. Aquaculture Aquaculture is the rearing or cultivation of aquatic animals or plants for food in natural or controlled environments e.g. oysters, mussels, salmon, tuna Mariculture refers specifically to the culture of marine organisms

5. So why farm seafood? Increasing pressure on wild fish stocks means aquaculture is a growing industry Increasing demand for high quality seafood that can’t be met with wild stocks Relieve pressures on wild fisheries

6. How are oysters grown? Oyster farming operations can be broadly divided into three stages: Spat collection On-growing Harvesting

7. Spat collection Wild larvae previously caught on tarred wooden sticks Sticks placed in areas where spatfall (settling of spat) most reliable Sticks often moved to low spatfall areas to reduce ‘overcatch’ Oysters then knocked off these sticks around 6 months of age Plastic catching slats used today

9. On-growing Variety of techniques used to grow oysters Broadly grouped into two groups Tray culture Longline system

10. Tray culture Some form of container or tray that sits on supporting rack Trays typically 1.8 x 0.9m Timber frame with plastic mesh bottoms, placed on timber racks Main advantage: allow precise stocking densities

12. Longline or floating culture Plastic systems have been developed to reduce the amount of tarred timber used in cultivation Baskets, bags and tumblers are used Some oysters grown subtidally on rafts or on floating culture Floating culture: gear moves through the water column with the tide

14. Husbandry requirements Filter feeders - require clean water Water testing and meat testing conducted Oysters need to be graded – sorted into similar-sized groups Drying oysters Strengthen the adductor muscle Kill off overcatch Reduce risk of mudworm (parasite)

15. A timeline of operations Catch slats put out for oysters to settle on (Feb) Spat stripped from catch slats, graded and put into nursery lease in fine mesh bags (Nov) Grading and thinning occurs every 3-6 months Oysters that are continually in the water need to be dried out For harvest: clean mud off oysters, remove dead oysters, grade, bag up

16. Any questions??? Next excursion: the business of oyster farming