The primary objective of this SARE-funded experiment is to explore whether alternative and locally available feeds can be cost-effectively used to raise tilapia.
Feed costs comprise the biggest expense in raising tilapia, constraining expansion of tilapia farming. At the same time, there is a small but expanding market for this food fish as evidenced by the amount of frozen tilapia being imported.
To test whether locally grown feeds could be used to rear these food fish, 1,000 red tilapia fries imported from a hatchery in Guam were divided equally between two fish tanks.
One group was fed commercially available floating tilapia feed. The second was fed only the ground leaf material of two locally grown crops, kang kung and sweet potato. Both have high protein and both are abundant on the islands.
Both types of feed were measured until the 10-week stage of the project.
Several complications arose during the project that precluded an accurate comparison of the two feeds. Among these were an irregularity of the water supply between the two tanks, curtailing of the water supply during an attempted second test and a change in technical advisors in the early stages of the project.
At the 10-week stage, because the tilapia performed poorly on the local feeds, the project team decided to switch to commercial feeds to salvage the fish for market. The poor growth may have resulted from degraded water quality or from the locally grown feed.
At six months, the fish were harvested. Those reared on the commercial feed weighed an average of ½ pound. The fished reared on the local feed weighed a maximum of 3 ounces.
While the project was terminated at harvest, coordinator Nicolas Songsong says he hopes to replicate the project with improved monitoring and the assistance of a new technical advisor who is familiar with animal nutrition and feed processing.
“I will do this project with their help since I am committed to tilapia farming and, as chairman of the Rota Agriculture Advisory Council, I feel a commitment to helping all potential tilapia farmers of the island,” says Songsong.
Songsong says that while the potential benefits of such a project may seem small by mainland United States standards, the impact on personal and family income could be considerable if locally produced feeds could be found to replace commercial tilapia feed, which is estimated at 75% of the cost of tilapia production. However, he says, as the project failed to yield results, estimates of measurable benefits are unavailable.
FARMER ADOPTION AND DIRECT IMPACT
As the project has yet to be completed, no other farmers have opted to adopt local feeds for tilapia. One outcome, however, has been that since this project began three other farmers have constructed fish tanks to produce tilapia, and all three visited the project site to discuss tilapia production.
FUTURE RECOMMENDATIONS OR NEW HYPOTHESES
For such a project, Songsong advises close consultation with experts in food processing and animal nutrition, neither of which was available on the island at the time of the project. The Northern Marianas College staff now have the skills to help producers like Songsong produce a balanced feed in a form the fish would accept. Indeed, he says a future study may incorporate a supplement with higher protein, like processed fish waste from the local marine fishery.
DISSEMINATION OF FINDINGS
The project site has been open to visits by local farmers, several of whom stopped by to view the operation and discuss tilapia. In addition, the extension staff of Northern Marianas College and the Department of Lands and Natural resources have used Songsong’s project to promote fish farming in the region. In addition, Simon Ellis, secretary of Pacific Community Regional Aquaculture, visited the project three times.
Songsong was the only producer directly involved in this project.