Backyard Aquaponics
A place to discuss aquaponics

I have always been meaning to test the figures that have been bandied about as to FCR (Food Conversion Ratio), percentage feed per day per fish weight and time to grow out to 500g, so decided to do the figures today.

Barra reputedly 1.2:1 FCR, feed @ 7% of body weight and grow out to ~500g in 6 months
Test 1:
Feed 7%
FCR 1.2:1
Start weight 100 fish @ 10g each
Barra will reach ~500g in 12 weeks (half the time as stated) and eat ~70kg of feed.

Test Run 2:
Feed 5%
FCR 2:1
Start weight 100 fish @ 10g each
Barra will reach ~500g in 25 weeks and eat ~110kg of feed.

Test Run 3:
Silver perch FCR 1.5:1, Feed 3%
Start weight 100 fish @ 10g each
SP will reach ~500g in 30 weeks and eat ~75kg of feed.

By changing the FCR to 2.5:1, the fish will be ~500g in 50 weeks, consuming ~130kg of feed.

So the FCR is probably a correct figure, along with the daily feed intake but these can’t be sustained for any length of time otherwise Barra would weigh 2.5Kg within 16 weeks

Soooooo...any comments

I've been led to believe that not all fish will grow out at the same rate Les

Some will be fatter than others.... suspect that in this case the accepted acronym FCR might be misreported....

I think there are so many variables within our AP systems that a standard FCR will be hard to determine.

70kg's of feed, damn how much does it cost?
much should i expect to send per kg?

The 70kg is theoreticaly to grow out 100 fish timmy. Expect to use more than that as we are unlikely to get that FCR.

In Qld we can get the pellets for about $50 for 25kg, so around $150 for 75kg.

oh i see, that's pretty good even if it cost you 2x that,
$300 for 50kg of barra is $6/kg, damn cheap

don't forget to factor in power and actually purchasing the fingerlings

but even cheaper buying a rod n reel n fishing licence lol

but thats not the point of AP

How many Barra do you catch down there in Melbourne BK.

none.....lol was thinkin trout

not really lol

huh - what do you mean. Me not understand

barra big in perth?

to catch i mean lol