Hatchery production of Oreochromis niloticus L. at different sex ratios and stocking densities
Share
Abstract
The 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.
Description
Contribution No. 228 of the Aquaculture Department, SEAFDEC.
Suggested Citation
Bautista, A. M., Carlos, M. H., & San Antonio, A. I. (1988). Hatchery production of Oreochromis niloticus L. at different sex ratios and stocking densities. Aquaculture , 73(1–4), 85-95. https://doi.org/10.1016/0044-8486(88)90043-9
Type
ArticleISSN
0044-8486Koleksi
- Journal Articles [1267]
Related items
Showing items related by title, author, creator and subject.
-
Growth and survival of Nile tilapia fingerlings in net cages without supplemental feed in Laguna Lake, Philippines
(Asian Fisheries Society, 1986)Oreochromis niloticus fingerlings were stocked at densities of 50, 100, 150 and 200 fish/m super(2) in fixed net cages in Laguna Lake, Philippines. These were reared without supplemental feed on 1 April-30 July 1980, 5 August-3 December 1980, and 19 December 1980-19 April 1981. Water temperature, dissolved oxygen, chloride level and pH for the three periods were measured outside the net cages. Growth rates were highest at 50 and 100 fish/m super(2) reared between April and July when phytoplankton biomass was high with a peak production observed in June (65.5 g/m super(2)), and zooplankton biomass ranged from 9.3 to 32.68 g/m super(2). Under these conditions, fish initially weighing 1.6-1.7 g grew to a marketable size of 106-124 g in four months. Those stocked at 150 and 200 fish/m super(2) had lower weights but still weighed over 80 g. None of those in the other two rearing periods exceeded 50 g after four months. Survival and fish yield during April-July were also higher than for those reared during the other periods. -
Practices and economics of successful shrimp farms in the Philippines
(Wiley, 2006)After reaching a production of 90,426 mt in 1994, production of black tiger shrimp (Penaeus monodon) in the Philippines has slowly declined and has dropped to only 35,493 mt, the lowest since 1987. Amidst the production failures besetting most of the farms in the country, a few farms man- aged to turn around once again and operate profitably with some even expanding their operations and are the subject of this study covering 40 farms. The common characteristics of the successful farms were found to be as follows: (a) easy access to clean seawater due to relatively deep nature of the shoreline, availability of saltwater from well, or adequate reservoir area to treat new water; (b) clean and compact pond bottom either because these are located above the tidal level or have been backfilled heavily with crushed limestone; (c) use of healthy fry by ascertaining fry condition through proper diagnostics; (d) adequate aeration; (e) good feed management; (f) use of bioreme- diators such as microbial inoculants (often referred to as probiotics), fish or both; (g) long dry-out period or alternating shrimp with tilapia or milkfish effectively limiting shrimp production to only one crop per year; and (h) adequate production-based incentives to technicians and workers. When standardized into 5 ha farms under three stocking density conditions, the economic performances are as follows at density levels of 5/m2, 15/m2, and 40/m2, respectively. The returns on investment (ROI) are 106.7%, 66.0%, and 78.5%; the internal rates of return (IRR) 250%, 111%, and 142%; and finally a return on equity (at a loan/equity of 70:30) 355.8%, 220.1%, and 261.8%. -
Milkfish production and processing technologies in the Philippines
(WorldFish Center, 2007)This publication describes the various aspects of milkfish production in the Philippines. It covers these areas 1) technology development from a historical perspective, 2) milkfish seed production 3) grow-out in brackishwater ponds 4) grow-out in pens and cages 5)milkfish processing.
