WATER IN AQUACULTURE SYSTEMS To a great extent water quality determines the success or failure of a fish farming operation 3

WATER IN AQUACULTURE SYSTEMS Fish perform all bodily functions in water Eat Breathe Take in and lose salts 4

Water Balance in Freshwater Fish Salts Ammonia Large quantities of dilute urine 19

Water Balance in Saltwater Fish Drinks sea water Ammonia Small quantities of concentrated urine 20

Inadequate water quality causes more losses than any other problem! Water Resources Water quality Water quantity Water sources Inadequate water quality causes more losses than any other problem!

WATER IN AQUACULTURE SYSTEMS Physical Temperature Chemical (“No effect” limits)

Physical Characteristics of Water WATER IN AQUACULTURE SYSTEMS Physical Characteristics of Water “Universal solvent” 5

Dissolved Oxygen Importance Solubility Safe levels highest cause of mortality Solubility variables Safe levels > 5mg/l

Projected Dissolved Oxygen Levels for Ponds 7 Measured values 6 5 mg/l 4 Projected values 3 2 1 5 pm 10 pm 5 am 24

Uniform dissolved O in pond 2 29

High dissolved oxygen (warm) Low dissolved oxygen (cool) Decomposing materials 30

Turnover Turnover Low dissolved oxygen - possible fish kill 31

Relationships

Percent of Total Ammonia in the Un-Ionized Form at Various Temperatures and pH Percent Ammonia Temperature (F) (pH) 7.0 8.0 9.0 50 0.19 1.83 15.7 68 0.40 3.82 28.4 86 0.80 7.46 44.6 25

Nitrification NH3 NO2- NO3- nitrosomonas nitrobacter NO2- Requires 3 moles oxygen to convert one mole of ammonia to nitrate

Dissolved Gasses Problem gasses Problem sources Nitrogen (primarily) Popeye/exophthalmia dorsal view Problem gasses Nitrogen (primarily) Problem sources Wells and Springs leaky pipe

WATER IN AQUACULTURE SYSTEMS Water quantity parameters   Requirements are based on temperature-dependent and size-dependent standard metabolic rates for fish

WATER IN AQUACULTURE SYSTEMS Water quantity parameters   Suggested replacement times Linear Noncirculating – Circulating Suggested water velocity rates Circulating -

WATER IN AQUACULTURE SYSTEMS Water quantity parameters Flow measuring techniques   Flow meters Pond filling time – not very accurate

WATER IN AQUACULTURE SYSTEMS Water quantity parameters     Weir gauges Sharp-crested – if outfall consists of dam boards V-notch Trapezoidal   

WATER IN AQUACULTURE SYSTEMS Pre-Use treatment Sediment removal   Settling basin/pond –   Filtration – Gas stabilization (O2 and/or N2)   Slatted inflow boards   3

WATER IN AQUACULTURE SYSTEMS Pre-Use treatment Sterilization   Ultraviolet –   Chlorination-de-chlorination –   Temperature control Heating   Chilling 3

WATER IN AQUACULTURE SYSTEMS Water utilization Open water systems   Flow-through Water enters pond or series of ponds and exits with/without treatment 3

Water Sources Rivers, lakes and streams Surface

Springs Advantages few or no predators no pathogens Disadvantages

Wells Types Advantages no predators no pathogens Disadvantages low O2

Rivers, Lakes and Streams Advantages large volumes inexpensive Disadvantages excessive nutrients

Surface Advantages inexpensive Disadvantages contaminates 5-7 acre watershed per surface acre of water

Groundwater Advantages Disadvantages hard to drain removal of fish

Municipal Advantages no predators Disadvantages disinfectants chloramines

Water Quantity Ponds Raceways Cages Recirculating aquaculture systems

Ponds Minimum requirement 13 gal/min or 50L/min per acre Rational to replace evaporation

Raceways Minimum requirement 500 gal/min. or 1900L/min Rational

Recirculating Aquaculture Systems Minimum requirement varies depending on size of system Rational needed to backflush filters during harvesting

for Bio-Filter to Mature Time Required for Bio-Filter to Mature 0.8 8 NO 3 0.6 NO 6 2 NH 3 Nitrites & Nitrates (mg/l) Ammonia (mg/l) 0.4 4 0.2 2 0.0 2 6 10 14 18 22 Time in Days 22