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POND CARRYING CAPACITY Concepts of Carrying capacity Carrying capacity – Must be careful of overloading.

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Presentation on theme: "POND CARRYING CAPACITY Concepts of Carrying capacity Carrying capacity – Must be careful of overloading."— Presentation transcript:

1 POND CARRYING CAPACITY Concepts of Carrying capacity Carrying capacity – Must be careful of overloading

2 POND CARRYING CAPACITY Concepts of Carrying capacity Flow index: Density Index:

3 POND CARRYING CAPACITY Concepts:Factors 1.Density 2.Oxygen 3.Ammonia 4.Suspended solids

4 POND CARRYING CAPACITY Data needed: 1. Physical parameters Pond dimensions Water use Elevation above sea level Daily mean water temperature Water inflow rates

5 POND CARRYING CAPACITY 2. Chemical parameters: 3. Water discharge permit specifications: ammonia Solids phosphate

6 POND CARRYING CAPACITY 4. Feed quality metabolizeable energy (kcal/kg) Density Carrying Capacity (spatial requirements) W den = V*D i W den : Biomass (kg) per unit length (cm) D i : Density index (kg/cm/m 3 )

7 POND CARRYING CAPACITY Species kg/cm/m 3 RBT3.0 Steelhead1.5 Chinook salmon1.8 Coho salmon2.4 Atlantic salmon1.8

8 POND CARRYING CAPACITY Density-based permissible biomass in the rearing unit Bio = W den *L Bio: permissible biomass (kg) W den : biomass per unit body length (kg/cm)

9 POND CARRYING CAPACITY Oxygen carrying capacity Single-pass system W = F*L*I W: permissible biomass F: flow index (see table) L: length I: water inflow F value:

10 POND CARRYING CAPACITY Multiple-pass system (w/o aeration) Increases potential of fish health problems: accumulation of waste products Reduction in DO available Dependent on fall ht, water temp, elev., etc. Simple method - Life support index (from tables 14/15) should be reduced by 25% for first use and 30% for additional ponds

11 POND CARRYING CAPACITY Multiple-pass system (with aeration) Pumped air or pure O 2 Treat as single-pass (be careful) Risk of nitrogen supersaturation (acute >110%, chronic 102%) Water quality

12 POND CARRYING CAPACITY Circulating water systems - Similar concepts, but lower water flows - Generally need supplemental aeration - May remove dependency of fish on DO

13 POND CARRYING CAPACITY Ammonia carrying capacity - Ammonia in unionized form (NH 3 ) is harmful - End-product of protein metabolism Single-pass – Multiple-pass – may exceed limit of Accumulation with each reuse of water - Must reduce feeding rate

14 POND CARRYING CAPACITY Circulating systems - Accumulation due to increases water retention time - - Recirculating systems -

15 POND CARRYING CAPACITY Suspended solids carrying capacity – no reliable method to calculate Depends on: 1. Digestibility of feed (FCR) 2. Feeding techniques If solids accumulate – fish health problems

16 POND CARRYING CAPACITY Application of CC: Stock pond for take-out - number of fish (plus mortality) that are to be removed at a specified time 1. Establish date Calculate temp.-based daily growth rate (table 4) Nat. mortality ( % per day) 7.

17 PRODUCT DEFINITION Product potential/planning The 5 Ws: 1.Who 2.What 3.Where 4.When 5.Why


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