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POND CARRYING CAPACITY. Concepts of Carrying capacity Carrying capacity – Must be careful of overloading. POND CARRYING CAPACITY. Concepts of Carrying capacity Flow index: Density Index:. POND CARRYING CAPACITY. Concepts: Factors Density Oxygen Ammonia Suspended solids.

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## POND CARRYING CAPACITY

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**POND CARRYING CAPACITY**• Concepts of Carrying capacity • Carrying capacity – • Must be careful of overloading**POND CARRYING CAPACITY**• Concepts of Carrying capacity • Flow index: • Density Index:**POND CARRYING CAPACITY**• Concepts: Factors • Density • Oxygen • Ammonia • Suspended solids**POND CARRYING CAPACITY**• Data needed: • 1. Physical parameters • Pond dimensions • Water use • Elevation above sea level • Daily mean water temperature • Water inflow rates**POND CARRYING CAPACITY**• 2. Chemical parameters: • 3. Water discharge permit specifications: • ammonia • Solids • phosphate**POND CARRYING CAPACITY**• 4. Feed quality • metabolizeable energy (kcal/kg) • Density Carrying Capacity (spatial requirements) • Wden = V*Di • Wden: Biomass (kg) per unit length (cm) • Di: Density index (kg/cm/m3)**POND CARRYING CAPACITY**Species kg/cm/m3 RBT 3.0 Steelhead 1.5 Chinook salmon 1.8 Coho salmon 2.4 Atlantic salmon 1.8**POND CARRYING CAPACITY**Density-based permissible biomass in the rearing unit Bio = Wden*L Bio: permissible biomass (kg) Wden: biomass per unit body length (kg/cm)**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:**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**POND CARRYING CAPACITY**• Multiple-pass system (with aeration) • Pumped air or pure O2 • Treat as single-pass (be careful) • Risk of nitrogen supersaturation (acute >110%, chronic 102%) • Water quality**POND CARRYING CAPACITY**• Circulating water systems • - Similar concepts, but lower water flows • - Generally need supplemental aeration • - May remove dependency of fish on DO**POND CARRYING CAPACITY**Ammonia carrying capacity - Ammonia in unionized form (NH3) is harmful - End-product of protein metabolism Single-pass – Multiple-pass – may exceed limit of 0.03 - Accumulation with each reuse of water - Must reduce feeding rate**POND CARRYING CAPACITY**• Circulating systems • - Accumulation due to increases water retention time • - • - Recirculating systems • - • -**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**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 2. 3. Calculate temp.-based daily growth rate (table 4) 4. 5. 6. Nat. mortality (0.02-0.03% per day) 7.**PRODUCT DEFINITION**• Product potential/planning • The 5 W’s: • Who • What • Where • When • Why

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