Rabbitfish or siganid, Siganus guttatus – locally known as “danggit” in Visayan and Samaral in Tagalog – can now be grown in seacages.
This was recently proven by Cefegrino F. Toledo of he Pangasinan State University – College of Fisheries in Binmaley Pangasinan. His studies showed that siganid can be grown to market size in floating net cages measuring 1 x 1 x 1.3 meters each with 20-millimeter mesh.
Toledo stocked siganid fingerlings weighing 8.6 to 12 grams each in the cages at a density of 50fish per square meter. The fish were cultured for 122 days using four experimental fields namely: commercially formulated feeds (CFF) containing 25% crude protein (Treatment 1), CFF containing 30% crude protein (treatment 2), combination of 50% CFF containing 30% crude protein and 50 percent filamentous green alaga, Chaetomorpha linum or “lumot” (treatment 3) and lumot only (treatment 4).
Result indicated that commercial feeds had significantly better effects on growth and production of S. guttatus than the combination of 50 percent CFF and 50 percent lumot and lumot only. The highest mean weight gain of 77.7 grams per fish and production of 4.18 kilograms per meter cage were obtained with treatment 2 but did not differ significantly from the weight gain of 70.1 grams per fish and production of 3.86 kilograms per meter cage in treatment 1. Lowest growth of 40.8 grams per fish and production of 2.26 kilograms per meter cage were obtained with treatment 4. The result in treatment 3 ranked third, but did not differ significantly from growth and production of 44.9 grams per fish and 2.56 kilogram per meter cages, respectively. The mean rate of survival of the fish ranged from 89 to 98 percent.
Commercial feeds with 25 percent and 30 percent crude protein appeared to be economically feasible as feed for S. guttatus in cages . A net income of 104.10 pesos per square meter per cage and a benefit cost ratio of 1.422 were obtained from from fish fed with the CFF containing 30 percent CP.
The project was funded by the DOST and coordinated by the Philippine Council for Aquatic and Marine Reserch and Dvelopment – Manuel P. Garcia (Mariano Marcos State University).
Source Greenfields, 1993