Backyard Aquaponics
A place to discuss aquaponics

I make a really nice seaweed and cucumber salad with lemon/soy sauce dressing. That would go great with the Sushi from the sushi farm.

OK, so have side-by-side AP systems, one fresh and one salt. On the freshwater side, you have cucumber and wasabi. On the salt side, put in kelp and your favorite sushi fish. HEAVEN!!

Sounds like a plan Janet.
I know nothing about kingfish or mulloway myself.

Their black bream are handling 22ppt salt, well down on seawater, (35ppt or something i think.)

I keep having to remind myself they are coming at things from an aquaculture perspective, not AP. The issue with saltwater recirc is what to do with ur waste water. This is yet to be solved conclusively at an industry level here in Victoria.

I love the idea of a big tank growing kelp and fish, man that is cool.

Barramundi Blue are working on saltwater recirc systems in Korea, not sure which species of plants they are using, but likely kelps

And it can be used in conjunction with abalone production as well ...

never thought of that...................................

but then wouldn't live rock and coral be producers of nitrate versus consumers?

Had our first field trip yesterday to Steve at Otway Yabbies, 25 minutes south of Geelong. He has given up on beef and sheep and has some 20 dams on the go for yabbies. Great 3 hour trip and very helpful info.

He supplies the aquarium trade only and is breeding blue yabbies with great success. The blue colour is a recessive gene so when harvesting, he sells all non blue yabbies as bait etc. Undersize blues go back in the dam for further growout.

He has permits for several different species and is one of the few with a permit for keeping the freshwater spiny cray. Got some thumpers that he has knocked back big money for.

Also has fast growth CSIRO yabbies that he is going to mate with his own top growers, in his new dams and measure growth definitively.

Has plenty of ideas and no time for govt pencil pushers. Being of Polish descent, he tends to take them on and usually wins!

A really insightful trip. Steve is big on the future of aquaculture in Australia and was encouraging all of us to take it up as a vocation.

Does not supply the food trade atm, simply doesn't have the volume. His system is extensive, low stocking densities, lotsa dams. He relies on planted trees for yabby feed and has some unique bird scaring setups. Said he once cut a cormorant open and he had 10 blue yabbies in his gut, (20 bucks worth,) so he takes his bird scaring very seriously! Well worth looking up for those with a keen interest in crustys.

Interesting stuff TT, he only gets a couple of bucks each for the blue yabbies? boy they put some markup on them in the shops..

That's for the small ones. The 300gram ones wholesale for 20 bucks each! Steve sends most to Asia and has 2 main clients in Melbourne I think.Don't get me started on aquarium margins, those guys are up there with the best of them.

He has knocked back a grand each for mature spiny freshwater crays, just wants to get some breeding going. It was a really interesting and informative trip.
I will get Andrew Christie, our lecturer,to email me some photos and will post them here sometime this week.

Here the wholesale price is at the most 1/4 the retail price.

I'd love to see some pics, I'm surprised he's not using a more intensive system. I would think there would be much better control on the quality and an increased production.

He has 2 options, extensive is a lot easier for him to manage. He has plenty of water and with a heap of natural feed, a low stocking rate , he is going this way at the moment. Should he start supplying the food trade down the track, he has the infrastructure to upscale pretty quickly.

Ripper night on Tuesday covering off the water cleaning side of an Aquaculture setup, plus a video on production of silver perch and murray cod fingerlings. The murray cod brood stock were magnificent specimens of 5kg or so, in rude good health. The courtship ritual with the silver perch brood stock was captured on film and very touching. I love these fish.

Learnt the whys and wherefors on foam fractionaters, ozone filters, UV filters, drum filters etc. It's all about removing solids and killing pathogens prior to return to fishtank, having the water "polished" as they say. I tend to think in AP our water is no where near as free of tiny solids, but our generally lower stocking rates give a better margin for error.

As i will not be able to use a UV filter in my setup,(indiscriminate, it kills everything good and bad), I am going to have to be on the ball in other areas of my filtration, given my stocking density. Ozone likewise is an unaffordable luxury. It is quickly finding favour on a commercial scale though. The trick is to have it inline post bio, but far enough removed from the tank so it has time to do its thing b4 breaking down to 02 in the return line.

I am inclined to think I will run a series of screw capped 90/110 mm stormies inside the shed, post sump, in the future. Will have a bank of say 10 and fill em with bio balls and trickle down back to the fish tank. If nothing else it will make me feel better.

We were told that bio conversion from ammo thru to nitrate is better in a taller vertical bio column, which is different to how we do things in AP, (broader, shallower beds.) I found that interesting and would like to run side by side tests one day.

Lots of other stuff but my brain is exploding and need beer. "Homer eats Whopper take 75."

Second field trip today. A big thank you to Leigh at Eildon Trout Farm. They are on the Goulburn River just west of Eildon and have an 18.5Meg/day water licence. It is a flow thru system. The water comes into the property at a DO level of around 9ppm and is thrashed with various aerators across the property.

Water is pumped into a small rise on the farm via a 2 foot pipe from the river. The pump runs 24/7 and has been in operation 6 years. The pump costs a grand a week to run! Their only water cost is $1500/yr for their licence. Gunna be in for a rude shock when the true cost of water is factored into our brave new dry world.

From the concrete tank on the rise, everything is gravity fed thru smaller pipes. One concrete fingerling tank 15m by 1m by half metre deep had 25,000 fingerlings in it! Only 5 weeks old, they were already a good 6-7cm in length. They get fed hourly 8 times/day and love their tucker. Typically the food is 50% protein, they use 800kg a week and buy it at $1.50/kilo.

There are about 4 growout ponds of about 50,000lt each and one pond that holds the brood fish. The ponds are lined with rock, so they prolly lose a lot of water to seepage. Ribbon is run across the ponds to prevent predation by cormorants. Water drains in one end then out the other and off the property. They reckon it is cleaner when it leaves than when it comes in.

Once the fish get to 250plus grams they are seined into the final growout tank before being dispatched to an offsite processing plant. Prices ex farmgate are $8.30kg at the moment.

They had massive problems and losses last year with the heat. One other farm I visited today said they were losing a ton of fish per day at the height of the summer heat earlier this year. Ouch.

The market prefers female fish bc they are a little lighter in colour and milder in flavour. They are able to breed for females these days.

The property is a bit old school and needs a capital injection. It is labour intensive. Ponds cannot be drained for harvest, so everything is grunt work, seining thru flowing water. Tuff stuff. The fact is their water costs nothing, over heads are reasonably low and prices are firming. They don't record things like mortalities of fingerlings or pH. Seems they hit a few key numbers and the joint ticks over. (Having said that, someone must be on the property at all times in case of pump failures etc.)

A recirc system would struggle to compete with this sort of setup. Much higher startup costs, higher buy prices for water, pay to get rid of it etc etc.

I really like the idea of rainbows in an AP setup, they grow so fast. This means more nitrates quicker and has implications for stocking rates and fishtank to plant ratios. The ONLY downside I see are the excessive summer water temps. I am almost inclined to onsell my silvers next March, buy advanced rainbow fingerlings and grow them out til next christmas. See how we go.

Called into another farm on the way home. A kid had just caught a 2.6kg Atlantic Salmon. Magnificent looking specimen. At $21/kg it cost his dad $55 to take home and cook. It was a mature young female full of eggs which was a bit of a shame. Ripper looking fish and I bet they are smacking their lips tonight.

Dasall.

trout are great in AP, biggest fish i've grown so far, and no mass deaths................will be interesting to see what temp i can keep them to..................

Put it thisway, my AP system not green housed and running 24/7 spends more time in the trout growing range than it does in the SP growing range.

And while SP can survive 10C they don't take kindly to stresses or handling at that temp. besides my ap system went well below the 10C mark running cont. this winter

yes I am still only 13-14C but don't have the duratough on for another week. See what happens then.

Lonely here, but we will soldier on!

Fish handling last night at Tafe. Basically, knock em silly with clove oil, measure and weigh them. A few drops of clove oil in 10lts (approx 2 gallons and change) is all you need to subdue ur fish. Net out from tank into a bucket of their own water with another bucket of their own water beside, which is the recovery tank. Have ur airstones on hand in each vessel. Net from ur ex tank vessel into ur clove oil bucket and wait until the anaesthetic (sp) does the job. Splash some tank/bucket water on ur scales/bench/hands, tare ur scales to zero and weigh. Can measure with ruler on the scales at the same time, just tare the lot to zero to begin with.
Carefully but firmly (stop them wriggling), transfer fish to recovery bucket with airstone. They will recover in a couple minutes. Then place gently back in their tank.

The fish will suffer no ill effects and you will know how big and heavy ur fish are! Easy peasy.

We did sleepy cod and silvers last night. The sleepy cod had distended stomachs. We are hypothesising that their pellet food is not perfectly suited to their dietary requirements and they are converting a lot of food to fat. Further study required here!

The silvers looked magnificent. 15-16cm in length and just under the 100 grams. They looked terrific on the scales. Nice shape, colouring etc. Just a good looking fin fish. As an aquaculture species, their growout tends to be a bit slow compared to murray cod, barra and jades. As an aquaponic species they would appear hard to beat. Attractive appearance, good eating, reasonable growout, hardy and able to handle a variation of water quality and temps. There is an awful lot, aquaponically speaking, to recommend about these fish.

Recovery times in water with air, is only a couple minutes, then they can be placed back in their tank.

Watched an interesting video on the McRoberts Grading Tank. It is a recent Aussie design that takes the stress out of commercial grading. Very simple, clean, stress free for the fish. Anyone know anything about these guys?

Dasall.