Grouper Culture in Netcages: WPU Experience

Abstract

This paper documents the use of cages for rearing or holding juvenile groupers to marketable size as experienced by the Western Philippines University (WPU) Puerto Princesa Campus. Groupers were cultured in floating netcages in a brackishwater pond and in floating netcages in the open waters of Puerto Princesa Bay. Both projects, the brackishwater grow-out pond in Sta. Monica and the floating netcages in Puerto Princesa Bay are owned and managed by the University.

The primary and secondary data on grouper culture, either as income-generating or research activity from 1998-2000 were used in the study. Discussed in the paper are the guidelines in site selection, cage construction, seed collection, proper stocking, sampling scheme, feeds, feeding and the use of fish aggregating device and lift net to collect trash fish.

Major findings are the performance and survival of the cultured grouper at varying densities. The average growth rate per day of cultured fish range from 0.90 to 1.0g for fish having size of 10-150g, it increases to 1.0 to 4.0g on big sized fish (159-450g) usually on the later part of culture period. The culture period ranged from 7 to 8 months from juvenile stage. Survival ranged from 80% to 95%. Based on a 9-unit netcage measuring 2.5m x 2.5m x 3.0m, an annual net income of PhP70,000.00 is expected with the ROI of 50% with less than 2-year payback period.

Since mortality of small-sized groupers is commonly observed, it is recommended that monthly sorting should be done to attain higher survival.