VB's Aquaponics System - Silver Perch & Jade Perch

veggie boy

Beeso - I haven't eaten any of my silver perch because despite being bigger than the jades when purchased, they are not plate size yet.

My verdict is that jades grow so much faster than silvers that provided you can maintain the required temps then jades are the go. Winter is the challenge, though I think once I have the greenhouse in and have the tanks in the shed - duly insulated, that I will be able to grow jades year round with the addition of a bit of solar heating. Silvers can be grown with jades - but I am only likely to buy silvers again if they prove to be tastier than the jades (unlikely I suspect). I am keen on getting some Barra later this year, but they will have to be grown in a different tank.

beeso

i just like havig a few things like the redclaw in the tank as well and the jades are no good for that no?

veggie boy

I haven't tried them with redclaw. I'd say it would depend upon their size. Yabies would be part of the natural diet of Jades. They are not particularly agressive. I have goldies with my jades without issue.

twintragics

How much fatty deposit did they have in their gut VB? Seems to be a bit of a thing with both Silvers but particularly Jades.

veggie boy

Gut was full of fat. I am eating another tonight and this time took a picture of the fat from the gut. I will post it when I get a chance.

Jaymie

are they Purple King beans VB? They look good

veggie boy

Just finished eating my second Jade. This time I filletted and crumbed it (not my prefered method - but thought I'd give it a go).

The verdict is that yes Jades are a beautiful tasting fish - but if filletting I think skinning may be in order because there is a thin layer of fat deposit inside the skin over the whole fish. If you eat this it can be a bit sickly. On the second fillet I peeled the flesh off and left the fat deposit stuck to the skin - this is very easy to do and is an alternative to filletting. If cooking whole - I'd also be using this method to avoid consuming all the fat.

For those who aren't aware - this fat is good fat, very high in omega 3. Just a bit sickly to eat it all - particulary if eating a whole fish (which is maybe where the real issue lies, because a 500 gram plus fish provides quite a lot of flesh. The fillets on the fish I ate tonight weighed 350 grams.

veggie boy

Jaymie - yes, purple king. Taste good too. It's just a shame I only have one plant. Will have to try harder next time.

RupertofOZ

Quote:

From the Ausyfish site :

View of the large lump of fat found within the body cavity. Compare the fish on the right which was photographed immediately after being captured in the Barcoo River, the natural habitat of the Jade Perch. The fish on the right has little fat within the body cavity. All the organs are clearly visible. With the one the left, it is difficult to find any of the fishes organs.
This fat is also present in Silver Perch grown in ponds, however Jade Perch have a little more of this fat. Anglers who have caught and eaten these fish from the Barcoo River also report seeing a large “lump” of fat in the gut of the fish. The fish comes from a very hostile environment. Fish in Australian rivers must be able to cope well with the “feast and famine” nature of the rivers systems in this country. After flooding the natural food supply for these fish is abundant. This glut of food is a contrast in the extreme compared to a drought situation where the fish will find getting a feed very difficult. Also during winter (usually the dry season) the fish are relatively inactive and probably rarely feed.

The stored fat will be used to help the fish survive in these situations. In aquaculture, fish are grown in an artificial environment such as a commercial fish pond or a recirculating system. They are in fact being kept in a “feast” situation. The fish grow rapidly and store fat as quick as they can, to be ready for the “famine”, which never comes. If your market finds this fat undesirable, perhaps a low protein, low fat, diet and a reduction in food will reduce the level of fat produced by your crop of fish.

It is our belief that a reduction in the frequency of feeds will also help. Reducing the food while the temperature is high should result in the fish burning up its fat reserves. Probably the optimal temperature for growing this fish is around 27C. Once the fish reaches your desired market weight try keeping the temperature up while reducing the feed intake. For every 10 degrees Centigrade the fishes metabolic rate is doubled. Therefore they burn up energy at twice the rate. You should also be aware that the fishes need for oxygen is also doubled.

twintragics

Ta. I have a theory bubbling away in the back of my brain that we could keep them for an extended period with no feed, prior to eating them. If they simply use their fatty deposit as an energy store, they would continue to contribute to the grow bed system until they have used their fat store. The trick would be to be able to determine reasonably reliably how long it takes to use that stored energy b4 the fish starts to lose condition. Watchyathink?

RupertofOZ

See above TT :wink:

monya

nice work VB. Interesting on the fatty underside of the skins. I skinned Joel's silvers because they were a pian in the arse to scale. Did the jades scale easily or was skinning them easier?

beeso

perhaps we need a new forum "recipes and preparation"

RupertofOZ

One already here besso ... Fish Recipes

veggie boy

I didn't skin the fish. Found them relatively easy to scale - though the scales are small, so a fine teeth scaler is the go. I think it would take quite a long time for the jades to burn up their fat store. TT you are correct that you could continue using them to supply nutes to the grow-bed while not feeding them, as they will metabolise the fat and continue to produce ammonia - mainly through gills I would think. For mine though - given that it is generally going to be grow-beds and not fish that I am short on, then I'd prefer not to have fish sitting in the system any longer than they need to be.

Feeding at too high a rate would seem to be a mistake though and lower protein foods the go. I also wonder whether the fat could be utilised for anything????

Backyard Aquaponics A place to discuss aquaponics

VB's Aquaponics System - Silver Perch & Jade Perch

Backyard Aquaponics
A place to discuss aquaponics