(Manila Bulletin).- Most fish farmers today raise one fish species at a time. Either these are bangus or tilapia -- the top two farmed fish in the country in ponds, cages or pens.

Marlo Pagulayan of Brgy. Cabasan in Peñablanca, however, is an exception.
 
The diligent farmer, a BFAR Region 2 cooperator, harvested recently 374 kilos of tilapia, 42 kilos of ulang (giant freshwater prawn) and a small quantity of carp from his 810-square meter fishpond project. Initial stock was 4,050 pieces of the three species. For every three pieces of tilapia, two pieces of ulang were stocked.
 
The innovation, polyculture technology in fisheries parlance, enables farmers to double their net income as compared to purely tilapia farming.
 
Production cost for his polyculture project was P16,500 while the net income was P27,000.
 
On the other hand, production expense for a monocrop of tilapia in a similar area is estimated at P26,100 and the net income is R14,000. Thus with polyculture, he got an additional P13,000 without additional expense.
 
Pagulayan was able to cut on cost by feeding the ulang with 55 percent indigenous diet such as vegetables and snail.
 
According to Hermogenes Tambalque, extension division chief of the fisheries agency, polyculture is the scientific process of raising two or more non-competing species in a common production pond.
 
By noncompeting, the aquaculture expert means that fish should not predate against each other and not compete directly on the feed supplied.
 
"In our project in Peñablanca, a lead time of one month was allocated for the ulang in order to avoid predation by the tilapia. The stocks did not compete with each other given their different feeding habits. By nature, tilapia are surface feeders while the ulang acted as pond cleaner being bottom feeder," Tambalque explained.
 
Other feasible stock combinations are tilapia-carp-ulang; tilapia-carp-hito; tilapia-seaweed-mudcrab and others.
 
Polyculture is the same as intercropping in crop production, BFAR Region 2 Regional Director Jovita Ayson said. "Polyculture is already a mature technology that has not caught on due to our farmers’ innate fear of change."
 
"Our project has proven feasibility and profitability of the technology in actual field practice. We are confident that other farmers have learned and will adopt this technology in their own projects," Ayson added.

Source: http://www.mb.com.ph