Monday, October 10, 2011

Redecorating to accommodate brooding

I originally designed this high tunnel aquaponics system as a production facility rather than as a brooding system.  This means that I had intended to get all-male fry via Fed Ex every 3 months and to simply grow them out to market size.  That plan was simple: just one big fish tank and one big grow bed.

I have since changed my mind and decided to set up my own hatchery operation to brood my own fry.  A hatchery operation (or, if you prefer not to emphasize h's when they lead off words, "an hatchery operation") has different needs than a pure production system.  These needs can be conveniently met by digging out pools in the grow bed to serve as nurseries, but at a cost of reduced filtration and reduced grow space for plants.

I'm now redesigning my system to accommodate the needs of both a hatchery operation and a production operation.  I can squeeze in a nice hatchery operation if I convert 1/3 of the grow bed into a series of nursery pools, and I've calculated that I can convert 1/3 of the grow bed into fish pools if I decrease the peak density in the main fish tank from 1/2 lb fish per gal down to 1/4 lb fish per gallon. 

Below is a pic of the progress to date. Fry collect in the small pool (aka "fry pool"). When they're about 3" long I'll transfer them to the larger pool (aka "fingerling pool"). After another 2-3 months I'll transfer them to a large pen in the big fish tank for their final growout phase.

So in a nutshell, the cost of adding a small hatchery operation to my existing high tunnel aquaponics system is that I'll only be able to produce about half as many adults.  At that rate, I hope to harvest 200 1.5lb fish every 2-3 months, giving me a total of 1,200-1,800 lbs in annual fish production.  We'll see how it goes...