An Organic Aquaculture System

James B. Dekorne elaborates on the advantages and disadvantages of an organic aquaculture system in a hydroponic greenhouse built in New Mexico.


| January/February 1975



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A collage of pictures of the aquaculture system.


MOTHER EARTH NEWS STAFF

For the benefit of MOTHER EARTH NEWS readers who may have missed the previous segments of the series, this is the last of four articles describing the various components of an experimental, underground hydroponic greenhouse and aquaculture unit recently built on my homestead in the mountains of northern New Mexico. The present installment deals with aquaculture.

Aquaculture is the cultivation of fish or other cold-blooded aquatic animals such as mussels, clams and crayfish under optimum controlled conditions. Fish farming — perhaps a more descriptive term — has been practiced for thousands of years in the Orient, and has recently become a profitable business in the United States. Catfish are raised on large farms throughout the South, and in Louisiana crayfish culture has proven to be a profitable commercial venture. In mountainous states such as Idaho, where an abundance of cold running water is available, fish farms provide the market with pan-sized rainbow trout at premium prices.

In this country, aquaculture — like most other farming — is run along agribusiness lines, with an eye toward maximum yields and maximum profits. Fish are "packed like sardines" in ponds or tanks in which the water is constantly circulated, filtered and aerated to keep the inhabitants from dying in their own waste products. These fish feedlots make use of high-protein "chows" manufactured by the major livestock ration companies, and hence bear no relationship at all to the organic low-energy aquaculture operations of the Orient . . . which, interestingly enough, consistently outproduce the "agribiz" methods normally used in America.

I became interested in organic aquaculture in 1971 after reading a series of articles on the subject by Dr. John Todd and Dr. William McLarney in Organic Gardening and Farming magazine. These two researchers, working at the New Alchemy Institute in Woods Hole, Massachusetts, have been experimenting for many years with low-energy organic food-producing methods designed for homesteads and small communities. In an article entitled "Aquaculture on the Organic Farm and Homestead", appearing in the August 1971 issue of OGF, Dr. McLarney summed up the rationale behind fish farming:

The best argument for aquaculture is based on the ever-increasing need for protein foods. Fishes and aquatic Invertebrates are far more efficient food converters than their warm-blooded counterparts, since they need expend little or no energy supporting their weight or maintaining their body temperatures. They are thus capable of producing more protein per unit area from the same amount of food. 

Compare Robert Rodale's comment on the food-converting efficiency of warm-blooded animals (OGF, April 1971):

wayne_1
1/31/2009 10:11:39 AM

I understand that this piece was written in the 70's and there have been many advances in aquaculture since then. The following is my plan for my own compost heated aquaponics/greenhouse. I am just as broke or broker than the author seems to be and I believe in making everything as near self-sufficient as possible. I will be raising some Tilapia that eat vegetation and hope to feed them mainly on duckweed,and some sunfish that will be fed on combination of earthworms,crickets and mealworms that i will raise in the greenhouse as well as flying insects attracted to light in warm weather. To maintain water temp and greenhouse temp I will use compost heated water tempered with cold water. All waste laden tank water will be filtered through flood and drain vegetable beds planted in lava rock or similar small gravel. The bacteria that makes it's home on the gravel convert the fish waste, both solid and liquid, into usable plant food. after the water leaves the fish beds it will be further cleaned in shallow ponds with duckweed to polish it off then leftover runs down hill to my in ground pond or to my garden in summer. The heated water in tanks and heat from compost piles should be enough to keep the vegetables growing in winter.Remains of fish after harvest will be used for poultry feed and fertilizer.The poultry manure will go into compost pile to supply heat. As I build the system I will do a more detailed report but that is the gist of it.






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