Characteristics of water parameters and their effect on fish welfare Flashcards
RAS =
recirculated aquaculture system
Benefits: saves water
safe (fish can’t flee)
higher and more stable production
fast growth
FCR =
feed conversion ratio
fish have a really good one of these compared to mammals. 1kg feed = 1 kilo fish growth
FIFO
fish in - fish out
The Fish In: Fish Out (FIFO) ratio has been widely utilized to gauge the efficiency of fish use in animal production, particularly in aquaculture.
The fish-in fish-out ratio (FIFO) was calculated as the quantity of live fish from capture fisheries required for each unit of farmed fish produced.
water efficiency
flow-through systems take the most
RAS less
3 most important things for fish farming:
water
oxygen
temperature
30-60 kg of fish can live in 1 cubic square of water, 200 kg for eels
NO2-> NO3
nitrites become nitrates via oxidation
choose your water flow based on
type of fish: bottom dweller vs pelagic
Why does the shape of your fish tank matter?
shape affects water flow
bottom may also be sloped.
octagonal tanks are even a thing, they are self-cleaning due to physics. for some reason round tanks tend to eventually fall apart. octagonal lasts longer.
How do recirculated systems work?
water from fish tank ->
mechanical filter ->
biofilter ->
degasser (trickling filter) ->
oxygen enrichment->
UV disinfection
waste compounds from fish farming (7)
ammonia,
ammonium
nitrite NO2
nitrate NO3
phosphate
CO2
sludge (organic matter + biofilm etc.)
Normal salinity in a fish farm is around
3%
optimal biofiltration when: (3)
6.8- 7.5 pH
O2 minimum 5 ppm
temp. 10- 30’C
increased nitrates causes a fish’s blood to
to turn dark
the nitrifying process produces
acid, H+, and thus the pH level falls.
in order to stbailize water pH,
a base must be added.
he did not finish the pp on 17.3.25
