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Thursday, January 22, 2009
The Tough Tilapia
| The tough tilapia by Maria Rowena Briones | |
The Philippines is 9th in the over all ranking of aquaculture production in the world. Indeed, among the fisheries sector in the country, it is also the best performing sector during the last 15 years.
The aquaculture industry has grown tremendously with the onset of hatchery and culture techniques. These developments are fuelled by the need for alternative sources of marine products as our supply from natural fish stocks is nearly depleted and yet the demand is continuously increasing due to increase in human population.
Tilapia is an introduced species in our inland waters. The first strain, Oreochromis mossambicus, was introduced in 1950. To date, there are five additional strains Oreochromis. aureus, Oreochromis niloticus, T. zilii, red tilapia and the genetically improved farm tilapia. They contributed in the development of a strong aquaculture industry since 1972.
At present, tilapia dominates the fish population in our fresh water areas. This is mainly because of its capacity to reproduce and grow quickly, and to survive in a low oxygen environment such as stagnant ponds and fish pens. They are also known to be disease-resistant and can adapt to low quality inputs and varied environmental conditions.
Aside from the high growth rate and adaptability of tilapia, one of the reasons why its production is gaining momentum is the acceptability of tilapia as a source of protein in the diet of all the social classes in the local and international markets.
However, aquaculture, they say, is a double-edged sword, it solves our economic problems on one hand but exacerbates our environmental problems on the other. This is true for growing tilapia, as inputs are intensified and stocking densities are increased to maximize production and increase profit.
In some lakes, proliferation of tilapia led to the depletion of weak indigenous species. Also, the increase in the number of fish cages and pens in shallow lakes and rivers alter the natural productivity of these bodies of water. The uneaten feeds of tilapia become toxic substances, like ammonia and hydrogen sulfide, for other fish stocks. Too many cages also hinder waves and water current leading to lake euthrophication or the decrease of dissolved oxygen in the water. These conditions are rampant in the lakes of Sampaloc and Mohicop, Laguna, Taal, Batangas and Sebu.
Despite these threats, subsistence fisherfolk consider tilapia as a blessing as it increases their catch and their income. This is also true for the middle class fish cage and fishpond operators. Because they can afford the inputs needed to increase profitability of the industry, they look forward to tapping markets abroad by venturing on big scale tilapia production.
The government is promoting increased productivity in aquaculture, as any increase in fish production on our part could only come from this sector. Included in the program for the aquaculture sector is increasing the productivity of brackish water and freshwater fishponds, sustainable development of swamp and marshland fisheries and marine sea cages.
Since research in fisheries is a crucial element in the development, management, conservation, and protection of our fisheries and aquatic resource, the National Fisheries Research and Development Institute was created under the Philippine Fisheries Code of 1998 (RA 8550).
Dr. Ruben Sevilleja, director of the Freshwater Aquaculture Center in Central Luzon State University, in his paper on small scale aquaculture and adoption of genetics-based tilapia technology, that he presented in the Agri-Policy Forum disclosed that there are only few research on the structure and characteristics of the aquaculture industry thus they can only surmise who are the main beneficiaries of the growth of the industry are. He emphasized the need for further research on the role of subsistence aquaculture in the Philippines and how farmers can benefit from the latest aquaculture technologies.
This forum was sponsored by the Bureau of Agricultural Research (BAR) and the Philippine Institute for Development Studies. BAR plays a pivotal role in the over all monitoring of research activities of DA agencies involved in fisheries. Monitoring is especially necessary in the trade offs that we do to meet the demands for fish and the limitations of our environment where we draw the resources that make us live. 
Sources: Fishery Country Profile of the Philippines. Food and Agriculture Organization Fisheries Department (http://www.fao.org); Tilapia and the Environment. (http://www.american.edu); Small scale aquaculture and adoption of genetics-based tilapia technology. Paper presented in the 14th Agri-Policy Forum on Socio-Economic and Policy Issues in the Aquaculture sector held last May 6, 2002 by Dr. Ruben Sevilleja; The impact of tilapia fishery and culture in the Philippines: Report on rapid rural appraisal of DEGITA project. Paper presented in the 14th Agri-Policy Forum on Socio-Economic and Policy Issues in the Aquaculture sector held last May 6, 2002 by Dr. Melchor Tayanem.
Wednesday, January 21, 2009
Tilapia GMT
One of the major undertakings of the FGBP is Phil-Fishgen, a project designed to disseminate the products of collaborative research on sex control in tilapia and to generate income for the financial sustainability of future FGBP research activities.
The Tilapia
Tilapia is a tropical fish species originating from Africa. Due to its popularity for aquaculture it has been introduced around the World and is widely cultured throughout the tropics and sub-tropics. Tilapia is a common name for a group of three genera, Oreochromis, Sarotherodon and Tilapia, with the Nile tilapia, Oreochromis niloticus, generally considered the best species for freshwater aquaculture. The fish has many attributes suited to domestication and culture including good flesh quality and flavor, wide tolerance of different environments, resistance to common fish diseases, and relative ease of reproduction in captivity.
This ease of reproduction actually represents one of the ; principal problems in the optimization of yields in tilapia culture, the fish breeds too readily. Energy is diverted from growth, into the behavioral and physiological interactions between the sexes, and into the production of eggs. The most effective solution to this problem is to grow only one sex, preferably males as they grow faster and to a larger size. A number of technologies have addressed this problem including hybridization and hormonal sex reversal, but none produce monosex fish in a consistently effective, affordable and environmentally safe way.
The YY Male Technology
Through the application of simple genetic manipulations, the UWS, in collaboration with FAC-CLSU, have developed an innovative and robust new genetic technology for producing all-or nearly all-male progeny in the Nile tilapia. Known as the “YY male technology” this takes the form of a breeding program combining feminization and progeny testing, to produce novel males with YY genotypes (i.e. with 2 male sex chromosomes) instead of the usual XY male genotype. These YY males are known as “supermales” and have the unique property of siring only male progeny.
Genetically Male Tilapia (GMT)
The all-male progeny of YY males are termed genetically male tilapia (GMT) and are normal XY males (although some can “naturally” revert to female, giving GMT an average sex ratio of >95% male). The hormone treatments used in the breeding program to produce YY males are two generations removed from the fish that are consumed so neither the GMT or their YY male parents are treated in any way. This is an environmentally friendly technology requiring no special facilities for application. A series oif on-farm trials of GMT were conducted in the Philippines, including all major types of culture system ranging from extensively managed earthen ponds through to intensive, tank based farms.
The GMT proved to have excellent properties for aquaculture, cost effectively producing significant increases in yield of uniform sized fish and controlling reproduction in all culture systems (see figure). YY males, which are as viable and fertile as normal males, can now be produced in large numbers and are being used commercially to mass produce high yielding GMT for tilapia growers in the Philippines, through a network of licensed and accredited hatcheries.
GMT produced higher yields, through a combination of enhanced survival and faster growth rates, in 11 the farms on which it was tested. These higher yields were accompanied by lower food conversion ratios and greater size uniformity, factors which also contributed to the improved profitability of culturing GMT compared to present available stocks. GMT have shown similar increases in performance in intensive culture systems in other countries.
abalone
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| | Why abalone hatchery? � Hatchery technology has been developed by SEAFDEC/AQD � Wild or hatchery-bred broodstock spawns spontaneously throughout the year � Abalone feeds on the seaweed Gracilaria, and the technology for seaweed culture is an easy one � High demand for juveniles by culturists for grow-out culture � Less competition being a new aquaculture technology | |||||
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SEAFDEC Laboratories
To support and promote research, development, and dissemination of new aquaculture technologies
Molecular Microbiology Laboratory
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Establish fish cell lines for use in the diagnosis of viral diseases
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Find alternatives to antibiotics
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Develop vaccines and immunostimulants against aquatic pathogens
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Find microbes for treatment of aquaculture wastewater
Molecular Endocrinology and Genetics Laboratory
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Develop strategies to enhance the reproduction and growth of aquaculture species
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Examine genetic variation among wild and domesticated stocks of animals and plants in aquaculture
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Find molecular markers for parental pedigree analysis to facilitate selective breeding and genetic improvement
Algal Production Laboratory
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Optimize use of algae for industrial and medical applications
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Find algae for pollution control and wastewater treatment
| Fish Feed Technology Laboratory | |
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Aquaculture sector eyes biotechnology to boost production
Aquaculture sector eyes biotechnology to boost production
MANILA (PNA) -- To meet the growing demand for local food supply and emerging markets for marine products, the aquaculture sector is turning to biotechnology for ways to develop better fish spawns and even develop biofuel from marine algae.
"Aquaculture production should increase to meet the demand for fisheries products," Evelyn Grace T. de Jesus-Ayson, scientist from the Aquaculture Department of the Southeast Asian Fisheries Development Center, said.In Southeast Asia, consumption of fish products is seen to balloon to 19.7 million metric tons by 2020, from the 14.1 million MT in 2000.
Production, meanwhile, is seen to grow only 19.7 million MT by 2020 from 16.0 million MT in 2000, not enough to meet regional demands, she said.
Biotechnology refers to any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for a specific use.
In her presentation "Global Status and Prospects on Fisheries and Aquatic Biotechnology" in UP Diliman, Ayson said applications of biotechnology in aquaculture includes control of reproduction, genetic characterization and population genetics, aquaculture nutrition, control of diseases, growth enhancement and transgenesis, genetic characterization and population genetics and high density culture of micro-algae.
She said that enhancing genes of fish and other aquaculture products is not a new technology, and has been adopted in other countries for many years now.
"We have a system for producing recombinant fish growth hormone protein," she noted, saying biotechnology can develop pathogen-resistant strain of fish which can help resolve food security concerns.
In 2006, her agency undertook the development of a microsatellite DNA parentage marker suite for black tiger shrimp Penaeus monodon. Black tiger shrimp has a big demand in local and export market.
Aquaculture biotechnology also offers solutions to global warming as chemicals derived from sea organisms yield high potential for the production of alternative fuel.
"At present, there is growing interest in high density culture of microalgae for use in biofuel production," she said.
Microalgae comprise a vast group of photosynthetic, heterotrophic organisms which have an extraordinary potential for cultivation as energy crops, experts say.
They can be cultivated under difficult agro-climatic conditions and are able to produce a wide range of commercially interesting byproducts such as fats, oils, sugars and functional bioactive compounds.
Certain microalgae are effective in the production of hydrogen and oxygen through the process of biophotolysis while others naturally manufacture hydrocarbons which are suitable for direct use as high-energy liquid fuels.
However, though a promising field, Ayson said biotechnology is still being greeted by criticisms and controversies such as health and security issues.
Issues about transgenic fish include risk to human health, food safety issues, toxic compounds, allergens hormones and adverse environmental impact(s).
"For many aquaculture systems, we should expect transgenic fish to escape and enter natural waters," Ayson said. (PNA)
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