Backyard Aquaponics
A place to discuss aquaponics

Somewhere, roughly a year ago, I posted the local newspaper article about this one. At the time they had supposedly moved from tilapia to yellow perch. Frozen tilapia from Central America can retail for a less than $3/lb. Fresh tilapia will be less than $6/lb. The problem with yellow perch is that if the water temp falls below 68F they will sexually mature, or in other words they will eat a lot of food and not gain weight. They are usually harvested at a third of a pound to half of a pound in the round (150g to 225g.) At the time of the newspaper article they were selling yellow perch out the backdoor for $15/lb in the round. Assuming half the fish will be waste (it might be 60/40 waste to fillet at that size, I can't remember) you need two pounds of fish to get one pound of scaled fillets, which is how they are traditionally eaten around the Great Lakes. If you let them mature it takes two years to reach a third of a pound. I saw one paper that did it in a year with an indoor recycling facility. While they can sell the produce directly to grocery stores, you can only sell fish live. Once you kill it you need to be USDA inspected and while that is not the end of the world, it does add extra headaches.

Not only do you need to pay for electricity for grow lamps, but the bulbs need to be replaced once a year. And those bulbs aren't cheap even in bulk. On the other hand not seeing the plus side of 0F for two weeks in January does send the heating bills soaring even in a well insulated building. Milwaukee has plenty of old industrial buildings, so I doubt rent is much. I've run the numbers on several different setups for Wisconsin, and they rarely come out well. It's my opinion you need scale to do this in very cold climates, and that means a million dollars or two in capital. Growing Power admits they aren't profitable and are sustained by contributions. I think the company around Baldwin, WI (which is close to Minneapolis/St Paul MN) using the waste heat from their dairy operation to heat the aquaponics greenhouse is on the right path. But the farmers I've met either aren't that ambitious (they're planning retirement) or are struggling and don't have the time or the money. Still, the cold around here has obviously frozen a lot of brains for the better. By my count Wisconsin is host to three commercial aquaponics ventures and Growing Power, which is currently raising money for a five story aquaponics building.

Great info Caribis thanks for posting. Sounds like they are dreaming big and If you're going to dream, might as well dream big.

I noticed their not for profit was listed as having mountains of compost - I would think that using this for heating would make sense. Do you know if they have done anything of this sort?

I have no idea but I doubt it. Not when you have all that methane.

Caribis, maybe I missed something about Sweetwater or are you referring to the dairy when you mention the methane. Sorry if I wasn't clear, I was talking about the Sweetwater Foundation and Sweetwater Organics that last post, not the dairy operation. Apparently The Sweetwater Foundation has something to do with composting on a large scale.

The dairy operation you mentioned makes better sense. Lots of cities have methane digesters where they can collect and burn methane to heat with (usually on a small scale).