Browsing by Author "Bautista, Antonio M."
ArticleThe influence of various sex ratios and stocking densities on hatchery production of Nile tilapia, Oreochromis niloticus L., was studied in land-based (concrete tanks) and lake-based (hapa nets) systems. In both hatchery systems, egg and fry production was maximum at a sex ratio of 4:1 females to males and a density of 4 females per m2. Seed production varied significantly among treatments at different periods of the year. In concrete tanks, significantly high seed production of 12.98 and 11.77 eggs and fry per spawner per day was obtained in March and August, respectively. In hapa nets, irrespective of sex ratios, 10.18 seeds per spawner were collected daily in March. In relation to the broodstock density in concrete tanks, significantly bigger daily harvests of 13.41 and 13.00 eggs and fry per spawner were produced in late February and March, respectively. In hapa nets, daily harvests of 8.95 and 7.74 eggs and fry per spawner were the highest seed production levels which occurred in April and March, respectively. Seed production was significantly higher in concrete tanks than in hapa nets while insignificant differences (P>0.05) were found among sex ratio and broodstock density treatments.
Conference paperAM Bautista - In RD Guerrero III, DL de Guzman & CM Lantican (Eds.), Tilapia Farming: Proceedings of the First National Symposium and Workshop on Tilapia Farming, PCARRD, Los Baños, Laguna, November 24-26, 1986, 1987 - Philippine Council for Agriculture, Forestry and Natural Resources Research and Development; Bureau of Fisheries and Aquatic Resources; Aquaculture Department, Southeast Asian Fisheries Development CenterThe successful and profitable production of Tilapia nilotica in ponds or cages is predominantly influenced by the government and hereditry traits of the stock. Therefore, stocking of high quality fingerlings is a major mrequiment to ensure the profitable production of marketable tilapia in 90-120 days. There are reports on crossbreds of F1, backcross of two strains of T. nilotica stocked in net cages in the central bay of Laguna lake at 15/m2 during the months of May toAugust, reach marketable size of 100 to 180 grams in 70 days without supplemental feeding. It is not uncommon for tilapia farmers in Cardona, Tanay and Pililla, Rizal to harvest marketable outbred tilapia after three to four culture months from May to August. In the case of F3 inbreds of T. nilotica, stocks that have a certain degree of T. mossambica blood, growth is comparatively slower.