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Options in the development of the 'aquatic chicken'



By Dr. DAVID LITTLE, Institute of Aquaculture, University of Stirling, UK, and Aquaculture and the Aquatic Resource Management (AARM) Program, Asian Institute of Technology, Bangkok, Thailand.

As the new millennium approaches, tilapias are at last beginning to demonstrate their long-awaited role as the world's 'aquatic chicken". These are fish that can be raised in the backyard or by agro-industrial companies, grow fast on either natural grazing or formulated feeds, and are acceptable to both rich and poor consumers.

Few species match tilapias in terms of their potential to become the cultured fish of the future. As herbivores, they are less sensitive to the "fishmeal trap" facing much of the world's commercial aquaculture and can be raised with a much smaller 'ecological footprint'2 than the carnivorous shrimp and salmonids that are currently dominant.

A range of systems is suitable for tilapia, from low input pond and paddy fields to intensive production in feedlot cages and tanks. Commercial systems now exist in fresh, brackish and full-strength seawaters and, although most tilapia are farmed in Asia, production is soaring in the Americas and expanding in Africa.

Just as improved germplasm, nutrition, and health management characterized the development of commercial broiler chickens, so too have these issues become major concerns of agribusiness aiming to diversify into tilapias. And international agencies, seeing tilapia farming as a convenient and reliable basis for rural development, have sought to research simple farming systems, identify new approaches to avoid over-breeding and develop faster growing strains to improve opportunities for poorer people.

Tilapias, as with chickens, breed easily and their culture has not been constrained by seed production per se. They have the important characteristic not shared by other cultured fish species that make it possible to combine raising fish to eat with producing seed for sale or restocking. While a virtue for subsistence production, this becomes a problem for commercial operators aiming to produce larger fish of uniform size.

As male tilapia grow faster and larger, all-male production is an obvious goal. However, though the technique of hormonal sex reversal is well established, its adoption by hatcheries has been uneven and is still mainly the preserve of well-resourced private sector entrepreneurs and agribusiness. Public sector and small-scale hatcheries have failed to produce seed of predictable quality in a sustainable manner because of the relatively complex management and levels of investment required.

The development of genetically male tilapias (GMTa), in which YY "super males" are crossed with normal females to produce all male seed, raises the prospects of mono-sex seed being produced under simpler hatchery conditions. The approach is currently being field tested in the Philippines and Thailand with useful results, but work to improve the consistency of sex ratios still continues.

An alternative, or complementary approach, also being promoted in Asia is selective breeding for growth and other traits, which has resulted in the development and dissemination of synthetic strains with high potential to national centers throughout Asia the so called genetically improved tilapias 4(GIFT). However, these too are yet to be evaluated in a wide range of production conditions.

The rapid expansion, and future potential of tilapias as a food commodity needs to be understood if research and development is to be targeted in the most effective way. Although the differences in 'commercial' and 'subsistence' tilapia culture have long been appreciated, technical, economic, and demographic changes over the last decade now prompt a reassessment. Below we propose a framework for categorizing current tilapia production systems in terms of a range of factors including their relationship to markets and various beneficiaries. The focus of improved strain development as the best way to meet the diverse needs of tilapia producers and consumers is questioned. An alternative approach that recognizes seed availability as the central issue is proposed.

Framework for tilapia production systems

In contrast to the simpler dichotomy of modern feedlot and traditional backyard systems apparent in broiler chickens, our research has indicated that tilapia production systems are evolving into three distinct categories, which we define as smallholder (I), commercial (II) and industrial (III), as outlined in Table 1.

Tilapias have become widely established in smallholders' ponds and ditches throughout the tropics, often fulfilling a similar role to indigenous 'weed' fish (Table 1, I).

In much of Asia, individually owned systems are often contiguous to larger community-managed water bodies, at least during times of flood, and the fish raised are often indistinguishable from local feral stocks.

Tilapias have spread in a similar way in coastal areas. Irregular restocking of such systems may occur by using a neighbor's seed; typically, newly introduced strains quickly become introgressed with local strains. This category of tilapia culture is often poorly understood from farmers' perspectives. We usually know little about the fish raised, although they are normally classified as hybrids of 0. mossambicus, and they are often denigrated by fishery biologists for their poor growth rates and effects on indigenous fish and ecosystems.

Although clearly sub-optimal in terms of potential yields, they can be important to the most marginalized individuals and groups, and have impact on the nutrition and livelihoods of the poorest rural people.

The second category is found in densely populated peri-urban areas of Asia where fish-eating people have gradually come to appreciate the overall value of tilapia, and production economics increasingly favor its culture (II). The concentrations of nutrients available in these areas, often human and livestock waste, make semi-intensive systems based on fertilization and supplementary feeding most viable.

In a swathe that cuts through southern China and Taiwan, the Philippines, Southern Vietnam, and Thailand to West Bengal, the market share of tilapias appears to be steadily increasing, often against traditionally cultured carps.

Seed, often variable in quality, is being produced and delivered through a range of locally developed hatchery systems. Typically, hatcheries are simple, pond-based and derived from farmers formerly producing food fish.

In some areas, improved quality seed are making inroads. Using all male fish to control reproduction and allow more predictable production of marketable fish can increase the acceptability of tilapias to both producers and consumers, particularly if larger fish (>250g) attract significantly better prices. In most places however, mixed sex fish are highly marketable with larger fish purchased by better-off consumers at a premium and small fish sold cheaply to the poor.

The third category represents the commercial "global product" companies that are establishing turnkey style operations where conditions best suit market needs and available resources (111). Data from the US Foreign Trade Division of the Bureau of the Census5 indicates that most fresh tilapia fillets are produced within a quick flight of the US. In contrast, quick frozen fillets can be profitably produced and shipped from anywhere in the tropics with access to sea freight, together with cheap and abundant feed, water, and labor.

The companies leading the production and export of quality tilapia into North America tend to produce fresh and frozen fillets intensively at limited production sites. Hatchery development is typically integrated with grow-out to assure quality and quantity.

Control of reproduction in stocked fish, by treating first feeding fry with hormones, has become an industry standard. Various strains of Nile tilapia (Oreochromis niloticus) dominate fresh water production but red tilapia, especially the "Florida red" (Oreochromis urolepis hornorum x 0. mossambicus) are used in saltwater systems.

Production in the tropics, with high temperatures year-round, can allow efficient all-male seed production in ponds, tanks, or hapas (see Bhujel et. al. next issue) to supply continuous demand of large grow-out operations. These operations have been conceived to produce and export, and local market demand is relatively insignificant.

Notably, the currently available strains have not impeded commercial, export driven production, whereas they are frequently attributed to preventing the "success" of smallholder farmers. Access to mono-sex fry and more intensive management may explain some of these differences but clearly, even when farmers do have access to tilapia seed of adequate genetic quality, there is often a failure to meet expectations.

A simple lack of nutrients and poor early survival of fry may well explain much of this "yield gap", which on analysis occurs in most smallholder systems in Asia6. Much of the focus of rural aquaculture development is to encourage intensification of smallholder systems through greater stock control and higher nutrient inputsa. Little impact can be expected from the introduction of "improved" strains alone.

Improving strains

Improved strains have been hailed as the way to upgrade tilapia production in areas where the fish are well established, and to increase their attraction in places where they are yet to be introduced or are unpopular. A good understanding of how farmers are currently obtain their tilapia seed, or why former introductions failed, is critical if dissemination is going to be cost effective and its impact sustainable. It is unwise to assume that local strains are inevitably "poor quality". Better to analyze how and why the fish are currently being managed and seek indicators of deterioration, maintenance, or improvement of the stock.

The practice of seed saving may have particular consequences for strain deterioration, with the possibility of larger, faster growing individuals being preferentially harvested and negative selection occurring.

A lack of perennial water, high predator levels, or seasonally cool temperature regimes, may also prevent individual households saving seed for use the following season, necessitating restocking from another source. For farmers with small backyard systems (I), in which tilapias are a minor part of their farming systems, seed are typically obtained from neighbors. Nevertheless, lack of seed has been found to be a major constraint to this type of farmer7.

In contrast to smallholder management of tilapias, or stand-alone agribusiness concerns, private sector seed production and trading has been critical to the development of commercial farmers (II). The role of such networks in disseminating improved strains is crucial to ensure any sustained impact. In the past, gains have been short-lived because of hybridization with current strains and because of market forces that favor productivity over quality8.

Where tilapia are yet to become commercialized, the problem may be more a lack of suitable seed production than lack of quality strains per se. In Northern Vietnam, a local strain of Nile tilapia that had been maintained for two decades performed well when compared to "improved strains" in terms of over-wintering and growth, and certainly to a level that warranted widespread dissemination.

Currently, collaborative researchabc between the Asian Institute of Technology (AIT) and Research Institute Aquaculture No. 1 is ongoing near Hanoi and in Thai Binh Province to develop seed production methods that can ensure large quantities of seed during the peak demand early in the season. Both over-wintering of tilapia fingerlings and the stocking of broodfish in irrigated spring rice fields are practical options that are being tested with farmers9.

A strategic plan has identified the need for a central government facility to take responsibility for mass production and distribution of breeders to local level hatcheries and for follow-up monitoring and maintenance of the quality of fish seed raised by farmers10.

In southern Lao PDR, a simple two-stage hapa-based tilapia seed production that produces known-aged fry at biweekly intervals is now being promoted by the provincial Department of Livestock and Fisheries for use by individual smallholders and communities wishing to stock small impoundments11, ac.

Production and trading networks were undeveloped in the region and methods for local small-scale seed production were required that prevented contamination with local strains that farmers considered unsatisfactory. The young, known-aged fry of the strain used (Chitralada) can reach consumable size (100-200g) before breeding and recruitment stunts individual growth.

The low monetary value of small, local strains of tilapia may be particularly important to the poorest, most marginal producers. In northwest Bangladesh, the question of encouraging improved strains has been complicated by recent research pointing to the importance of existing tilapia strains to women in meeting household nutritional needs.

This "invisible" system may have been largely ignored by scientists and development workers because of the few tilapias seen in formal markets and because most of the people raising them would hardly be considered "fish farmers".

Benoy Barman, an extension officer working with the Northwest Fisheries Project12a, using participatory techniques, found that women risked loss of access and control if their low value local strains were replaced by higher value, more marketable fish. Strategies are now being researched to improve productivity without undermining equity within the household. Clearly, the needs of those who currently benefit from tilapias must be studied before "improved" tilapias are developed and disseminated.

Framework for main types of tilapia production system

Category

I Smallholder

II Commercial

Ill Industrial

Main descriptors

Rural, few/no inputs organic spread, natural recruitment

Peri-urban

fertilized pond, hatchery-supplied seed

Isolated, vertically integrated, seed

production on-site

Inputs

None, fertile run-off, incidental fertilization

Wastes/fertilizers/supplementary feeds

Compete feeds

Systems

Small ponds, ditches, ricefields, community ponds

Large ponds

Raceways and cages, intensive ponds

Importance of self sustained seed

XXX

XX

XXX

Importance of linkages with hatcheries by trading networks

X

XXX

X

Primary reasons for farmers self sufficiency

Few options, minimal costs

Reduced costs

Assured supply, maintain and upgrade quality

Relevance of monosex

X

XX

XXX

Market

Poor, rural producers and consumers

Poor and middle-income, urban

Primarily export, domestic, urban better-off

Main Beneficiaries

Producers, maybe poorest within households, immediate community;

Local traders

Traders, land owners

Shareholders, processors, ice/equipment supplies, transporters, governments, grain farmers, importers, contract farmers

Other Stakeholders

Fish seed traders

Transporters, harvest teams

Co-users of water resource/wastewater

Major constraints

Erratic seed supplies

Poor quality seed, land-related costs, nutrient availability

Off-flavors, water availability, cost of feed and labor

Notes: X = least important, XX = medium importance, XXX = most important

Conclusions

A flexible approach to the development and introduction of new strains is needed. No one strain or approach is likely to meet the needs of all.

Monosex technologies are now standard among agribusiness tilapia producers, but adoption by semi-intensive operators has been limited because of poor availability of fry of consistent quality. This is related to the basic incompatibility of hormone feed technology to the resources available to smallscale, private sector hatcheries. Smallholder farmers (I) remain almost completely unaffected by new strains and monosex technologies. Seed supply networks seldom service this type of producer, who tends to minimize cash costs and for whom many seed may be an advantage.

Agribusiness, while drawing on public sector research when it can, is increasingly supporting its own strain and hatchery technology development. In areas such as Thailand and South Vietnam where semi-intensive commercial farmers are well established, there are risks to the urban poor if production shifts towards use of improved strains and quantities of small, cheap fish diminish.

It is highly desirable that impact studies should be carried out, involving all potential stakeholders, before any improved strains are disseminated.

References

1 Pullin, R.S.V. 1984. Tilapia-potentially an international food commodity. Infofish Marketing Digest 3, 35-36

2 See Folke, C, Kautsky, N, Berg, H, Jansson, A and Troell, M. 1998. The ecological footprint concept for sustainable seafood production: A review. Ecological Applications, 8,(1) Suppl. 63-71

3 Mair, G. C and Little, D.C. 1991 Population control in farmed tilapia. NAGA, The ICLARM Quarterly, 4 (2) 8-13

4 Eknath, A.E. et al. 1993. Genetic improvement of farmed tilapia: the growth performance of eight strains of Oreochromis niloticus tested in different farm environments. Aquaculture 111, 171-188

5http://remora.ssp.nmfs.gov/trade/index/html

6 Edwards, P., Little, D.C. and Yapkupitiyage, A. 1997. A comparison of traditional and modified inland artisanal aquaculture systems. Aquaculture Research, 28, 777-788

7 forthcoming in Little, D.C. and Hulata, G. 1998. Broodstock management, hatchery and nursery technology in (Eds. Beveridge, M.C.M and B.J. McAndrew) Tilapias: Biology and Exploitation. (Chapman and Hall)

8Little, D.C., Siakaw, D. and Juntana, J. 1994. Commercial production and marketing of Nile tilapia (Oreochroniis niloticus) fry in Chonburi and Chachoengsao provinces, Thailand. Naga, The ICLARM Quarterly, 17 (2) 14-17

9 Nguyen, Ph.D. proposal. Asian Institute of Technology, Bangkok, Thailand.

10 Little, D.C., Pham, T.A., Nguyen, D. C., and Mair, G.C. 1998. Towards a strategy for promotion of Nile tilapia in Northern Vietnam-research, development and extension. Internal document. RIA Number 1/AIT Aqua Outreach.

11 Innes Taylor, N. 1997. The extent and diversification of small-scale fish breeding. Monitoring report. APO-L (P37) AIT Aqua Outreach-Lao PDR.

12 Barman, B. 1997. Strategies for Nile tilapia (Oreochromis niloticus) production and its dissemination in Northwest Bangladesh. Ph.D. proposal. Asian Institute of Technology, Bangkok, Thailand

Acknowledgements

The Department For International Development (DFID - formerly ODA),UK, funds research into improved tilapia systems for poor people. This has included the secondment, for more than a decade, of the author to the Asian Institute of Technology, near Bangkok Thailand. Current work is being funded through DFID's Aquaculture Research Programme, together with support through the DFID Bangladesh Fisheries Programme and the AIT Aqua Outreach programme. James Muir edited the manuscript. All statements are the responsibility, of the author alone.

b Additional support provided by the Government of Denmark (DANIDA).

c Additional support provided by the Government of Sweden (SIDA).

Fish Farmer July/August 1998

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