Duckweeds considered as aquaculture feed in the Philippines

Fishery officials in Cagayan Valley Region in northeastern Philippines have introduced cost-reduction and productivity enhancement technologies.

 

The Bureau of Fisheries and Aquatic Resources (BFAR) has included the widespread promotion of duckweeds as supplemental feed for tilapia, bangus (milkfish), pangasius and carp in cognizance of high-input costs of aquaculture farming, particularly feeds.

 

Duckweeds are small flowering plants with a reported crude protein content of 18 percent to 42 percent.

 

In an earlier research made at the bureau's fish farm in Iguig, Cagayan has revealed the plant's viability as an alternative diet without adverse effect on the growth of tilapia.

 

An optimum feeding mixture of 50-percent fresh duckweeds and 50-percent commercial feeds will have higher growth rate compared to fish fed with commercial feeds, according to the study.

 

A 1,000-square-metre, semi-intensive fishpond using the duckweed feed combination has been found to cut farm expenses by more than P10, 000 (US$208.71) or more than 20 bags in the 4-month to 5-month culture cycle. More than P100,000 (US$2,080.71) can be reduced on expenses of a hectare of fishpond.

 

Fisheries and Aquatic Resources regional director Jovita Ayson said duckweeds can also help lessen dependency on imported corn as raw materials for feed, which is currently 90 percent of the total requirement. 

 

Local government leaders will reportedly earmark funds to establish 10 duckweed-demo sites for the region.

 

Other aquaculture technologies to be promoted are the polyculture and pangasius culture, she added.

 

Polyculture is the scientific process of raising two or more noncompeting fish species in single or common culture. It can potentially raise farmer's income through the optimum use of inputs and culture area, she said.

 

Polyculture projects involving the combination of ulang (Macrobrachium rosenbergii) and tilapia, carp and tilapia, and common carp and African catfish, have achieved from 98 percent in additional net income from 58 percent.

 

In pangasius culture, the fast-growing and hardy fish pangasius is the feasible specie in fishpond, fish cage and organic-culture systems under the region's weather conditions.

 

Other aquaculture technologies to be introduced are urban, upland and mangrove aquaculture and 45-day delayed feeding technology. The agency will also introduce a culture of high- value species such as abalone, sea urchin and mud crab.

 

The agency has targeted to produce 12.29 million fingerlings and a million oyster spats this year as measures to increase dispersal to local government units and fish farmers in the region.

 

BFAR will also distribute environment friendly fishing gears such as fish trap, troll line, long line and gill nets in addition to the implementation of regulatory activities. The bureau will also continue the widespread distribution and installation of fish aggregating devices or payao, she said.

 

Ayson said the interventions will help address the ongoing economic crisis and enable the region to produce 66,400 tonnes of fish this year or 7 percent more than last year.

 

Fisher production in Cagayan Valley stands at 62,057.96 tonnes, which corresponds to a 56.49-percent fish sufficiency level.