Farming Fish in Cages

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Photo by Hildy Maingay
The harvest stage of farming fish is pretty simple. Just lift the cage out of the water, or use a dip net if you just want one or two.

Aquaculture. For many people, this word conjures up images of technologically complex artificial fish-rearing pools (or at the very least, large ponds devoted exclusively to raising fish). Yet one of the most convenient forms of intensive home-scale fish production is probably best called cage culture. Put simply, it’s the practice of farming fish for food in floating cages! This uncomplicated technique is most commonly used in North America by commercial fish farmers, but as years of successful experimentation at the New Alchemy Institute farm in Hatchville, Massachusetts have shown, it could be employed by any individual who has access to an appropriate natural or artificial pond or lake.

Furthermore, the number of fish that can be produced in a single floating cage is astonishing. The current records for rainbow trout, channel catfish, and common carp — three oft-reared species — are all approximately 15.6 pounds per cubic foot. Therefore, a cage that’s only three feet on a side (totaling 27 cubic feet) could conceivably be used to raise over 400 pounds of fish! And in more practical terms, even a first-time grower should be able to achieve harvests of nearly four pounds per cubic foot, producing 100 pounds of fish in a 27-cubic-foot cage.

How Cage Culture Works

To understand just how fantastic that rate of production is, imagine a 3′ x 3′ x 3′ hole in your back yard filled with water. Then visualize 100 pounds of fish swimming around in it. That’s the “beginner’s yield” we’re talking about!

Most people are aware that actually trying to produce fish in a small hole would create serious problems long before that 100-pound harvest could be achieved, primarily because the creatures’ wastes and any uneaten feed would soon drastically pollute the water. If such contamination didn’t kill the fish outright, it would certainly retard their growth.

  • Published on May 1, 1983
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