Backyard Aquaponics
A place to discuss aquaponics

I think you had GPs at your place when I was there, what happened to them?

I read a lot of conflicting things about aquaponics. One of the themes that constantly comes up is how it takes time for your system to mature. I cant see how that could ever happen running trout in canberra when you have to kill 100% of them once every 6 to 9 months. It would be like your starting from scratch every year. Im also concerned that this would occur when my plants would be requiring peak nutrients over summer. I would have thought it would be much easier to run a system with fish that are present constantly so there are no big and sudden changes in nutrient supply.

Not so Brendan.... a 1kg+ wild caught Bass will be 3-4 years old... or older...

So have you tried it? If Bass take 3 or 4 years in the wild to hit a kilo, then you would expect them to grow much faster in an aquaponics setup, and if you harvest at 500g couldnt you expect to do it in a lot less time?

Not sure about bass but Cod grow really fast. I have to limit the amount of feed to the one large cod I have to slow it down. Since the begining of winter its almost doubled in size.
In the wild fish have to find there food so in AP they tend to grow faster because of the regular feeding and water quality.

"In the wild fish have to find there food so in AP they tend to grow faster because of the regular feeding and water quality"

Thats exactly what I thought....which is why I find it odd that Bass take 4 years to grow out in AP, or 3 or 4 years in the wild. It doesnt add up.

Are you talking about Murray Cod? They are another fish im interested in. What sort of growth have you had out of that?

My cod is feed chunks of fish so his growth rate is going to be higher than pellet feed. I have 70 ish cod fingerlings but will have to wait and see how they go. A lot will die because they don't take to pellets and the others will try and eat each other.

Well im hoping to feed mine fish aswell (carp). There are tonnes of those whiskery bastards in the local rivers, it seems a shame to have to buy food when I can catch tonnes of it for the price of a tin of corn.

just remember that as carp are a noxious species, being caught with a bucket full, dead or alive, is an offence, and carries a huge fine. I dont agree with it, but unfortunately thats the law as it stands.

Carp are on the way out in the local rivers due to the cod that they release every year. The cod are eating all the small carp and only the really big ones are left to breed.

"just remember that as carp are a noxious species, being caught with a bucket full, dead or alive, is an offence"

Do you honestly think we would be discouraged from catching carp by being penalised for having them in our posession? I dont think so. In fact the DPI website says this about catching carp.

"For smaller quantities, options include eating, using as pet food, or composting."

Pretty hard to do that if your not allowed to have them dead in your posession. Someone has given you a bum steer.

Hi brendan,

Might be time to get yourself a thread!

GPs all died. They didn't eat. I had 10 GP and 50 SP, and I now have 50 SP, all of which have overwintered nicely and are eating again.

As for the trout - it's not like that. The "3 years" maturity thing is about the diversity of microflora, not about the numbers. Basically each system is different, and it takes a couple of years for nature to select which bacteria are best suited for your system ("all bacteria are present, the system selects them").

So the fact that you take out trout means that you aren't resetting back to zero. Basically the number of bacteria reduce, but they're still there. And when you put fish in again, the system scales back up.

Second to that, you don't just run the system without fish. I put silverperch in to grow out a bit, and put next years silver perch into my other tank.

Hi Gemmell,

Yeah ill get my own thread when im setup.

So what happens to your plants when you pull all your trout in Nov or Dec? Surely the plants will miss out on the nutes they need to power through their growing season?

What size range are your silvers and how old are they?

Brendan

you make it sound like these people are reasonable. Perhaps you bumpkins in canberra get a better deal than the rest of the country, but it is illegal to possess, dead or alive, any noxious species. You can eat it, but you have to do it at the side of the river. taking it in your car to your house is an offence. you are transporting a noxious species.

directly from the victorian DPI website

"Carp is declared a noxious aquatic species in Victoria, which makes it an offence to possess, transport or release live carp, or use live carp (including all forms of carp and goldfish) as fishing bait."

There are other factors including the breaking down and slow releasing of nutrients by other organisms such as beneficial bacteria and earthworms. The plants do not just die because fish numbers are reduced or totally removed and plants can continue to grow though not a vigorously.

"you make it sound like these people are reasonable. Perhaps you bumpkins in canberra get a better deal than the rest of the country, but it is illegal to possess, dead or alive, any noxious species. You can eat it, but you have to do it at the side of the river. taking it in your car to your house is an offence. you are transporting a noxious species."

That excerpt of yours relates to live fish, not dead. I would be extremely surprised if you can find reference to legislation in victoria that prevents you from transporting a dead noxious animal to your home. If you can, your halfwit government really needs to take a look at itself, as there is certainly no legisltation in NSW or the ACT that prevents you from killing carp and taking them home.

From the same source you have cited:

The declaration of "noxious" fish does not mean that the species cannot be fished for, or eaten. Carp are widely
fished for, and the flesh is enjoyed by many people, with a variety of methods of preparation and cooking.

Seems like you bumpkins in Vic have the same rules as the rest of the country. If you want to debate this further i suggest we start a new thread as this doesnt pertain to the topic of Gemmells pro system.