Aquaponics and Fish Feed

Several times a week I get asked some variation of the following question “OK, so if aquaponics is sustainable, what do you feed the fish?”. Just happened again yesterday at the hair salon.

Here is the deal. Fish, like birds, reptiles and mammals, need a range of protein based on their species. Each species typically fits somewhere on an omnivorous spectrum ranging from piranha’s that eat protein almost exclusively to largely vegetarian fish like tilapia and carp. The protein that fish typically eat in the wild is….other fish. When we started raising fish in captivity (aquaculture) fish feed was carefully crafted by nutritionists to offer the optimal amount of protein (fish meal) to quickly grow each species of fish depending on where it was on that omnivorous spectrum.

“Where is the problem in all this?” you may ask. Well, the problem is with the fish meal. As I’m sure you are aware, we are overfishing our oceans at an alarming rate. In March 2009, the Food and Agriculture Organization of the United Nations reported that over 70% of fish species were currently endangered. Another study published in November 2008 in the Annual Review of Environment and Resources found that one-third of the world’s marine fish catches are ground up into fish meal. A study published in the journal Ambio reported that in 2006, aquaculture consumed 57 percent of fish meal and 87 percent of fish oil. We simply can’t keep using ocean caught fish to feed our farm raised fish.

We can avoid all these issues by just raising vegetarian-leaning fish on garden waste, duckweed, black soldier fly larvae, worms, etc. The reality is, however, that raising enough food so you can feed your fish….so they can raise your food… takes work, and space and most of us are short on both of those. I admit that I’m looking for the convenience of a commercial feed in a form I can feel good about. I suspect many of you are too.

There are several organizations currently developing alternative protein sources for fish feed. In an article by Rebecca Nelson in the latest edition of the Aquaponics Journal (issue #56, Q1 2010) three companies creating protein sources were highlighted. At Ohio State University aquaculturalists are exploring the feasibility of using soybeans to replace fish meal and plan to soon test the product on yellow perch. Scientists at the Agricultural Research Services and Montana Microbial Products have teamed up to produce a barley protein concentrate that can be fed to trout, salmon and other commercially produced fish. Finally, in Idaho Springs, Colorado Oberon FMR has just signed a deal with Miller-Coors to turn 5000 tons of beer sludge into 6000 tons of fish food flakes.

But all of this is being developed as commercial feed and will only be available to aquaponic gardeners if we demand it. I called Oberon a few weeks ago and asked them when their feed would be available. They said that it was still in test, but once it was available it will only be available if the feed packagers request it, who need it to be requested by us. Just for grins I called one of the feed producers Oberon thought might be interested in pelletizing and producing a vegetarian fish feed and they said “sure, we’ll do it, but it is a special order that we only do in 5000 lb batches”. Oh, and it only has a 6 month shelf life.

Is aquaponic gardening sustainable? Absolutely. It uses very little water, enables organic food growing in areas that couldn’t otherwise grow, and naturally recycles fish waste as plant nutrients. But we need to do better with our inputs.

The solutions to the issue of using fish meal are on the way but let’s insure that solutions are available to all growers of fish, not just the large commercial operations. The only way we are ever going to see aquaponic gardening reach it’s full potential as the easy, sustainable growing technique I know it to be is to demand an easy, sustainable way to feed the fish. Demand it!

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