Hatching of Cage Reared Nile Tilapia in River Water of Bangladesh

Transcription

1 Agricultural Science Research Journals Vol. 2(10), pp , October 2012 Available online at ISSN-L: International Research Journals Full Length Research Paper Hatching of Cage Reared Nile Tilapia in River Water of Bangladesh Uttam Kumar 1, Md. Mostafa Shamsuzzaman 2, Muhammad Mizanur Rahman 3 and *Subrata Sarker 1 1 Institute of Marine Sciences and Fisheries, University of Chittagong, Chittagong-4331, Bangladesh 2 Department of Coastal and Marine Fisheries, Fisheries Faculty, Sylhet Agricultural University, Sylhet Programme Assistant, IUCN (International Union for Conservation of Nature), Bangladesh Country Office, Dhaka. Corresponding Author s subratasrkr59@gmail.com Abstract Tilapia which is known as aquatic chicken is one of the most popular fish meeting the increased protein demand. Present study was conducted at Muhuri River to observe the hatching performance of cage reared Nile tilapia in river water. Maintaining water ph 7.8 and 7.6, Dissolve oxygen concentration (DO) 6, 6.8 and 7.1 mg/l, salinity 0.2 and 0.5, NO 3 concentration 11 and 14 µg/l and water temperature 27 o C and 26 o C and stocking 268 gm (female) and 300 gm (male) in cage 1 and 208 gm (female) and 335 gm (male) were recorded in cage 2, 73 percent hatching rate was recorded. Keywords: Nile Tilapia, cage Hatching, Bangladesh INTRODUCTION Fish culture is an important component for many rural areas of Bangladesh suffering from protein shortages. Aquaculture activities have undergone major improvements in recent years, although emphasis has been placed largely on increasing production targets (Hossain and Das 2010). Presently, Bangladesh has placed a high priority on aquaculture to meet the growing fish demand. Bangladesh is endowed with vast water resources in the form of ponds, dighis, lakes, streams, and rivers, natural depressions in coastal areas and estuaries, covering an area of 4.56 million ha (DoF 2006) from where fish can be produced profitably. At present, production of Nile tilapia (Oreochromis niloticus) has drawn considerable attention for production. Tilapia is the common name applied to three genera of family Cichlidae (Sarotherodon, Oreochromis, and Tilapia), including about 70 species (Meyer 2002). Tilapia is grown more easily than other fish species for either commercial or non-profit enterprises. Oreochromis niloticus is often chosen for its good cultural characteristics. Because of their rapid growth, tolerance to high stocking densities and poor water quality, high reproductive rates and low susceptibility to disease, tilapia is an excellent candidate for aquaculture production. They may be grown in open ponds, cages submerged in ponds, aquariums, or tanks on land. However, an adequate supply of fingerlings is not always available through established hatcheries. Tilapia fingerlings are most widely produced in ponds. Apart from being an important source of protein, aquaculture is recognized as a source of employment and an essential part of integrated rural development (Rogers 1983). The popularity of tilapia farming is associated not only with its potential as a source of food but also as an attractive investment activity (Bimbao and Smith 1988). Tilapias have been introduced into more than 90 countries on all continents except Antarctica (Pullin et al 1997). The production of single-sex populations of tilapia (Oreochromis spp.) is an important tool for aqua culturists to avoid unwanted reproduction and to produce the sex with a larger growth potential (Macintosh and Little 1995, Green et al. 1997). Study Methods The present study was conducted at Mohuri river (Figure 1) of Feni district a TRANS-BOUNDARY RIVERS of Bangladesh. The river takes its rise on the Lushai Hill of

2 569 Figure 1. Geographical location of study area Tripura in India and enters Bangladesh through Pasuram upazila of Feni district after flowing over the hilly regions of India. As such, the river is wild and often causes flash floods. At some places it demarcates the boundary between India and Bangladesh and flows into the Bay of Bengal after dividing the Feni and the Chittagong districts. The Muhuri is not wide, only 150 to 200 m wide. But the width increases towards the sea. The depth of the river is also shallow; people can cross it on foot during the low period. Close to the sea, the river is under tidal influence (Banglapedia 2010). Tilapia were imported from Thailand, acclimatized before stocking and stocked in culture cages. Broodstock from the culture cages were selected on the basis of their maturity spread genital organs, soft and deep red in female and light reddish grey in males. Brood tilapia were reared in cages (Figure 2), using locally available materials for cage preparation. Iron rods were used for the cage frames and low cost locally available plastic drums used as floating material. Green and black nets were used and numbered as cage 1 and cage 2, respectively. The bottom net is a fine mesh, while the mesh size of the side net is 1 mm. Total length of the frame is m and height is m. For net installation m is used and rest m is used for float installation. Float installation chamber is divided into two parts having m for each. Diameter of the float (locally available plastic drum) is m and length is m. Total area of the net is square meter. In the cage method, male and female tilapias were kept in the same cage with the ratio of 1:2, respectively. The number of male and female tilapia in cage 1 was 20 and 40 where in cage 2, there were 26 and 52, respectively. After stocking the brood stocks were feed twice daily by mixing vitamin C and E with pellet (floating) following 2 percent of the total body weight of the brood.

3 570 Figure 2. Schematic diagram of cage for tilapia brood rearing The eggs released by the female were fertilized naturally by milt of the male in the cage. Fertilized eggs were collected from the cage, though it took more time to collect eggs from the cages than from a pond. Then, the fertilized eggs were transferred into incubation jars with care. Previously, the jars were filed with filtered water to minimize the temperature and environmental shock. Continuous flow was maintained through porous pipe for aeration. The entire hatching process is shown in Figure 3. The relevant water parameters for culture are ph, temperature, dissolved oxygen (DO) and nitrate. The ph of the pond water was measured by a portable ph meter (sensitivity = ± 0.02). Surface water temperature was measured by a Celsius thermometer D.O., as per the procedure stated in Strickland and Parson (1968) and APHA (1995). Results Environmental parameters are shown in Table 1. During Figure 3. Overall process of Tilapia hatching

4 571 Figure 4. Average body weight of brood for cage 1 and 2 Table 1. Water quality of the river during the study Parameters stocking During Five days after stocking Ten days after stocking P H Dissolve oxygen (DO) (mg/l) Salinity ( ) NO 3 (µg/l) Temperature ( 0 C) Table 2. Data related to egg Date of egg collection June 4, 2011 (7 pm) Mass of egg 15 gm Number of brood 6 Total number of egg 2143 Color of egg Whitish yellow Average length of egg 0.2mm Average weight of egg gm Grade of collected egg First days eggs Date of egg collection June 4, 2011 (7 pm) Mass of egg 15 gm Number of brood 6 Total number of egg 2143 Color of egg Whitish yellow Average length of egg 0.2mm Average weight of egg gm Grade of collected egg First days eggs

5 572 Table 3. Hatching data of the tilapia Date Number of spoiled eggs Temperature (0 C ) Stage June 5, Morula June 6, Pigmentation June 7, Head sink June 8, Yolk sac resumption June 9, First swimming stage Hatching rate= 73% stocking, ph was found to be 7.8 and 7.6 after 5 days and 10 days after of stocking, respectively. This indicates a favorable water quality for tilapia rearing. Dissolve oxygen concentration (DO) was 6, 6.8 and 7.1 mg/l during stocking, five days after stocking and ten days after stocking, respectively. Salinity was recorded at 0.1, 0.2 and 0.5 for the same time interval as mentioned above. The NO 3 concentration of the present study area was found to be13, 11 and 14 µg/l for the mentioned three sampling period. Highest water temperature was recorded as 27 o C at five days and ten days after stocking the brood and lowest was 26 o C during stocking at cage. Average body weight (Figure 4) was found to be 268 gm (female) and 300 gm (male) at cage 1, where weights 208 gm (female) and 335 gm (male) were recorded in cage 2. Eggs were collected (Table 2) from the six cages on 4 June 2011 at Total 15 gm eggs were collected and color was found whitish yellow. Average length of the egg was recorded as 0.2 mm and average weight gm. Total number of collected eggs was All eggs were first day s eggs. After collection, eggs were transferred to the incubation jar and on 5 June 5 spoiled eggs were found at 28 o C, during morula stage (Table 3). On Day 2, Pigmentation stage, the number of spoiled eggs increased to 130 at 29 o C. During head sink stage on Day 3, the number of spoiled eggs, 415, became higher. But, on Day 4, yolk sac resumption stage, the number of spoiled eggs decreased to 30 at 26 o C. First swimming stage appeared Day 5 and all eggs hatched at 27 o C. The hatching rate was recorded at 73 percent. Discussion The present study successfully hatched tilapia from the cage reared broodstock in river cages for the first time in Bangladesh. James et al. (1997) found from their research that the hatching rate was 78 percent in a cage of tilapia broodstock, while the present study found 73 percent hatching rate for cage reared tilapia broodstock in river water. The hatching rates were obtained as a function of the different situations and systems of egg incubation. In this study hatching was successfully carried out at o C. Czerwinski (1961) observed spawning of 0. niloticus in 50 percent seawater (19 ppt) during growth experiments in concrete tanks. The Nile tilapia (0. niloticus) was reported to reproduce, along with T. zilli and S.galilaeus at salinities of 13.5 to 29 ppt in the Great Bitter Lakes of Egypt (Kirk 1972), while in this study, the tilapia brood were reared at Reference APHA (American Public Health Association) (1995). Standard methods. 19th Edition. American Public Health Association, Washington, DC. USA. Bimbao M, Smith I (1988). Philippine tilapia economics: industry growth and potential. Pages In: R.S.V. Pullin, T. Bhukaswan, K. Tonguthai and J. Maclean, editors. The Second International Symposium on Tilapia in Aquaculture, ICLARM Conference Proceedings 15. Manila, Philippines: Department of Fisheries. Bangkok, Thailand and International Center for Living Aquatic Resources Management. Banglapedia (2006). (d), Hatiya Upazila. Available at org/ht/h_0089.htm. (Last accessed on July 12, 2010). Chervinski J (1961). On the spawning of T. nilotica in brackishwater during experiments in concrete tanks. Bamidgeh 13(1): 30. DOF (Department of Fisheries) (2006). Fishery Statistical Yearbook of Bangladesh Fisheries Resources Survey System, Department of Fisheries (DOF), Dhaka, Bangladesh. Green BW, KL Verrica, MS Fitzpatrick (1997). Fry and fingerling production. Pages In: H.S. Egna and C.E. Boyd, editors. Dynamics of Pond Aquaculture. CRC Press, Boca Raton, FL, USA Hossain MS, NGD Das (2010). GIS-based multi-criteria evaluation to land suitability modeling for giant prawn (Macrobrachium rosenbergii) farming in Companigonj Upazila of Noakhali, Bangladesh. Computers and Electronics in Agriculture 70 (2010) James CM, SA Al-Thobaiti, BM Rasem, MH Carlos (1997). Breeding and larval rearing of camouflage groper Epinephelus polyphekadion (Bleeker) in the hypersaline waters of the Red sea coast of Saudi Arabia. Aquaculture Research 28: Kirk RG (1972). A review of recent developments in Tilapia culture, with special reference to fish farming in the heated effluents of power stations. Aquaculture 1: Macintosh DJ, DC Little (1995). Nile tilapia (Oreochromis niloticus). Pages In: N.R. Bromage and R.J. Roberts, editors. Broodstock Management and Egg and Larval Quality, Blackwell Scientific, Ltd., Cambridge,

6 573 Massachusetts. USA. Meyer DE (2002). Technology for successful small-scale tilapia culture (CRSP Research Report ). CRSP (Aquaculture Collaborative Research Support Program). Rogers E (1983). Diffusion and innovation. Third Edition, The Free Press,, New York, NY. USA. Strickland JDH, TR Parsons (1968). A Practical Handbook of Seawater Analysis. 2ed. Bulletin of the Fisheries Research Board of Canada, No.167.