Kona FoodMachine Rain Catchment Tanks & More Hapas

Location: Kona, HI | Published: 25 October 2010

Part of the project we did this week, which you can read more about in our October 28th journal post, was taking the four tanks which used to hold all of our fish and converting two into rain-catchment tanks, one into a breeding tank, and the other into a nursery tank.

The rain catchment tanks allow us to add water to the system as needed without using precious potable water. We desire to do whatever possible to have the FoodMachineâ„¢ be as environmentally friendly as possible and water is a scarce resource in Kona.

We took the other two tanks and installed hapas in them. Hapas are simply very fine mesh netting. We put these into the tanks before any fish are placed in the tank. These nets allow us to catch the fish as needed. For example, in the breeding tank we put five adult fish. Once the eggs hatch, we are able to use a piece of PVC pipe or wood and place it under the hapa. By starting at one end and pulling the net over it, we are able to isolate all the fish in one end of the tank. We then net out the adults, move them into the net on the other side of the tank, and then we are able to net all the babies and move them to the nursery tank.

The same principle applies to the nursery tank. A hapa is used so we are always able to access the fish. Once the fish reach about one inch in length, we will move a group of 50-70 of them into a pen that is in the large fish tank. This way we are moving groups of like sized fish at the same time.