The number of people venturing in what should be a sustainable economic activity also went up from four to 15 farmers, as noted during a workshop hosted by Northern Marianas College-Cooperative Research Extension and Education Services at the Pacific Islands Club last March.
The workshop also showed growing interest in backyard aquaculture among CNMI residents. The growth in the production of locally grown aquaculture products also indicates that CNMI aquaculture is heading in the right direction.
It was foreseen during the workshop that in five years or so, the CNMI can produce its own fresh food and reduce its dependency on imports. The islands can even prepare for the future increase in demand for these products.
Over the past three years, NMC-CREES’ Aquaculture and Fisheries Development Program has been helping local farmers build their aquaculture systems. To enhance the profitability of aquaculture, the extension agents continuously share knowledge and technology with interested groups or individuals.
NMC-CREES Director Ross S. Manglona, in his message during the workshop, thanked aquaculture extension agent Michael M. Ogo for his endless efforts in establishing aquaculture as a new industry in the CNMI.
There are now backyard aquaculture farms in Oleai, Finasisu and Dandan.
Some of them are already selling their tilapia and shrimp at the Sabalu and Tuesday markets.
Ogo said the success in tilapia and shrimp production will pave the way for other aquatic species that can be produced in the CNMI.
Back in 2008, CREES drafted a plan to further expand aquatic selection by introducing groupers, mullets and freshwater prawns in tank culture.
This aquaculture program also includes pathogen exclusion and prevention to protect the industry from the potentially devastating effects of suspected pathogens.
It’s not that hard
At the CREES nursery, there is a small-scale aquaculture system which is generally larger than a aquarium but smaller than a commercial pond.
Either tapwater of rainwater may be used in a backyard aquaculture pond.
An aquaculture system can use an earthen pond or an above-ground tank. Both have advantages and disadvantages.
The CREES nursery uses tanks that are easily removed without lasting effects to the land. They are easily drained and the water environment is easily controlled and maintained. The fish is harvested easily.
Tanks, however, require maintenance and replacement of parts like pipes and liners especially if they’re made with plywood.
Aside from aeration, tanks also require a filtration system to get rid of both the settleable and soluble solids. The settleable solids (fish manure that settles down to the bottom) have to go through a solid filter before they go to the bio-filter for the nitrification process. During this process, two bacteria — the nitrosomus and nitro-bacter —turn the ammonia (fish urine) into nitrite, then nitrate that can also be used to grow leafy vegetables.
As the nitrate goes away, the water comes back to the pond and tank.
In raising fish in the tank, carrying capacity or stocking density is important to determine profitability.
Each tilapia needs 25 percent of a gallon of water. So 3,000 gallons of water are good enough to produce 750 tilapia of considerably size.
For shrimp that usually stay in the bottom, one square meter area is fit enough for 100 shrimp.
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