Operation of Aquaculture Systems. Extensive Pond Culture Semi-Intensive Cage Culture Raceway Culture Intensive Recirculating System

Transcription

1 Operation of Aquaculture Systems Extensive Pond Culture Semi-Intensive Cage Culture Raceway Culture Intensive Recirculating System

2 Pond Aquaculture Structures for Extensive and Semi-Intensive Culture Constructed with Vertical or Sloping Sides Level Bottoms Gently Sloped to Terminal Drain Water Added Only to Replace Loss Thru Evaporation Treatment or Seepage Bottoms with >25% Clay to Restrict Seepage Need To Limit Seepage Unacceptable Cost & Can Grow To Ruin Pond ast great Expense Types: Watershed Ponds Fed by Gravity Downhill Rainwater or Streams Or Pump Fed Ponds

3 Pond Aquaculture Three Kinds of Ponds Soil Added Above Ground Level to Form Levees Pond Dug Below Ground Level Combination Dug Below Ground Level But Levees Formed from Excavated Soil Levees Must be Between 1 & 3 Times as Broad as High Vertical Walled Ponds are Exception Want Vertical Walled Ponds Because Depth Stays Basically Constant Pond Depth m at End Opposite Drain

4 Pond Aquaculture Sarawak Pond Levees

5 Pond Aquaculture Bottom Gently Sloped to Terminal Drain Allowing Full Drainage of Pond Levee Height Should be 0.5 m Above Full Water Level in Pond Pond Should be Plumbed with 1 or 2 Inflow Lines If 2 Can be Alternated to Allow Clean-Out If 1 Need O 2 at Harvest at Drain End of Pond Inflow Lines with Values to Regulate Flow From PVC Schedule 40 Remember Two Diameter X Pipes Carry Half that of One 2X Diameter Pipe (Area = πr 2 )

6 Pond Aquaculture Sarawak

7 Carp Aquaculture Papua New Guinea

8 Pond Aquaculture Czech Carp Harvest

9 Raceway Aquaculture Raceways: Culture Units Linked with Continuously Flowing Water May be Circular or Rectangular Typical Length Depth Width Ratio = 30 x 3 x 1 Raceways Composed of Plastic, Fiberglass, Concrete Can be Linked in Series Effluent Enters the Next Circular Raceway Tanks Used Extensively in Research Facilities Each Tank Being a Statistical Replicate Size Depends on Stock Size Being Cultured Largest About 10 m Depth 1 2 m

10 Raceway Aquaculture Serial Water Use Splashboards in Rectangular Tanks Needed to Re-oxygenate Water for Next Tank Circular Tanks Water enters Horizontally at Angle Setting Up Circular Current in Water Drain at Center Various Methods to Collect Suspended Solids in Water Uneaten Feed, Feces, Fragments of Dead Organisms Do Not Want Strong Flows at Drain Especially with Smaller Stock Restrict Flow Might Need O 2 Replenishment by Bottled Gas

11 Raceway Aquaculture In Open Raceway Systems Often Inlet for Raceways Only a Short Distance Upstream from Outlet Reuse of Water Not Practiced in Older Systems Need Good Control Over Effluent Water Chemistry Alternative Treat Effluent Before Allowing it to Mix Back With River Water This Accomplished with Combination Sedimentation & Biofiltration Also Some Now Practicing Partial Re-Use of Effluent Water Idaho Trout Farmers Along Snake River

12 Trout Farm Raceways

13 Hatchery Raceways

14 Tilapia Raceway Hatchery Malawi

15 Cage or Net Pen Aquaculture Can be Used in FW Aquaculture When Harvesting Poses Challenges Mostly Used in Marine Facilities Generally Floating (Sometimes Sinking) Units in Open Water Standard Cage with Rigid Frame All Sides Net Pens Generally Have Rigid Frame at Top Only In Both Netting Extends Downward 20 m or More Cage & Net Pen Frames Made of Metal Often Coated Nets Made of Nylon Mesh Anti-Predator Mesh Made of Plastic or Thick Netting -

16 Cage or Net Pen Aquaculture Marine Cages & Net Pens Can Be Huge Multiple Units Linked Together Watchman s House, Warehouse for Extra Feed & Materials Automated Feeders Usually Feed in the form of Dried Pellets Cages & Pens Anchored in Some Manner Flotation Provided by Various Materials Styrofoam Air Tanks Much of Salmon Aquaculture Industry Grounded in Cages and Net Pens Norway, Scotland, Chile, Canada & Japan

17 Salmon Cage Aquaculture British Columbia

18 Fresh Water Net Pens

19 Salmon Net Pens Chile

20 Feeding Time Nearshore Marine Net Pens

21 Fully Recirculated Systems Circulation Production Tanks with Dual Drains Solids Controlled with Microscreen Filters NH 3 Controlled by Biofiltration Aeration or Oxygenation Required with High Densities Backup & Alarm Systems (Sophisticated) are required Closed Recirc System Engineering Unit Processes Used to Treat Water so that Only Small % Discharged Daily Ranging from 10% System Volume per Day to 1% System Closure is Critical When Specific Water Quality Parameters are Absolutely Required or the Crop is in Danger of Being Lost

22 Recirculating Aquaculture Systems (RAS) Definition: Aquaculture System that Recycles & Renovates Water or Water That is Serially Reconditioned & Reused Recirculating Systems Semi-Closed System 5% Exchange per Pass 120% Exchange per Day Closed System 0-20% Volume Change per day Typical of the Most Modern Systems

23 RAS Pros Less Water Needed Ability of Easily Locate Less Land Needed Temperature Control Water Quality Control Waste Retention Better FRC Product Isolation Inventory Control Marketing Advantages Cons High Initial Investment Limited Existing Protocols Technically Demanding Start-Up Short Response Time Things Go Wrong FAST Limited Track Record Quarantine Out of System Limited Control Potential for Catastrophic Losses

24 RAS - Setting Up Most RAS Require <10% of the Water that Pond Systems Need to Produce Similar Volumes of Fish Water Traditionally Brought O 2 Maintained Temperature and Carried Waste Away Modern RA System Requirements Minimize Waste Production Conserve Water Concentrate Waste into Smaller Flows

25 RAS - Setting Up Most RAS Require <10% of the Water that Pond Systems Need to Produce Similar Volumes of Fish Water Traditionally Brought O 2 Maintained Temperature and Carried Waste Away Modern RA System Requirements Minimize Waste Production Conserve Water Concentrate Waste into Smaller Flows

26 Types of RAS Serial Re-Use: Water From One System Enriched With O 2 & Sent to a Subsequent One Partial Re-Use: Additional Treatment of Portion of System Water Volume & Then Re-Used Fully Recirculating: High Degree of Re-Use Additional Treatment Processes Separate Systems Major Limiting Factor: O 2 (Determines Density) Next Un-Ionized NH 3 & CO 2 (Remember CO 2 Affects ph ph Affects the Balance Between NH 3 & NH 4 +