SUISANZOSHOKU 48(2), 273-278 (2000)

Aquaculture Development: Challenges for the 21st Century

I. Chiu LIAO*1

Abstract: Aquaculture has a long history of more than

2,500 years. It has been quietly practised without much

attention until the 1960s. Since then, aquaculture has

played an important role in food production. In the mid- dle of 1980s, aquaculture production contributed only

14% of the world fishery production. At the end of 1990s,

contribution from aquaculture has increased to 27.6%.

Asian aquaculture has particularly shown its strength as

its production now makes up 91% of the total world aqua

- culture production.

The world population has already reached six billion

in 1999. At the present rate of increase, it is estimated

that world population will reach nine billion in the 2050s.

The increasing population is creating a serious concern

about the food availability in the coming century. As cap

-ture fisheries production has apparently reached the

maximum level in the 1990s, there is little chance that

more aquatic foods can be obtained from the wild to sat

-isfy the need for such large population. The whole

world, therefore, expects aquaculture to provide more

aquatic foods and other potential non-food products in

the 21st century.

This paper discusses the challenges that aquaculture

will meet in the 21st century, and provides recommenda

-tions which encompass both technique and non-tech

- nique aspects. The technique aspect includes the conti-

nuity of researches that are currently being conducted,

the applications of biotechnology with corresponding

precautionary measures, which are intended to produce better strains in terms of growth and disease resistance

and to formulate superior feeds, and the innovation of

aquaculture science which may find better ways to pro

- duce aquatic foods and utilize other aquatic organisms.

The non-technique aspect includes the establishment

and implementation of appropriate aquaculture laws and

regulations, education and extension service, and

strengthening international cooperation.

In comparison with the 20th century aquaculture, the

21st century aquaculture will take two major objectives:

one is to continue producing affordable aquatic foods

and the other is to supply high-value aquatic products

for specialized markets. This is different from aquacul

-ture in the past, which was intended only to satisfy the

basic human need for food. Furthermore, unlike the pre

-sent situation, the availability of resources for developing

aquaculture in the 21st century will be critical.

Therefore, different approaches will have to be adapted

to pursue the objectives in the coming century. The use

of ocean, which is an enormous resource for aquaculture

development, is foreseeable. Aquaculture in the future

will devote more in aspects of super-intensive recirculat

-ing culture system, automation system, deep ocean

water utilization, sea cage aquaculture, as well as stock

enhancement and sea ranching. To increase aquaculture

production, the diversification of culture species is inevitable. Exotic species may be introduced after thor

-ough studies. Aquaculture in the 21st century will pay

more attention to environmental conservation to make the industry sustainable and everlasting.

Key words: Aquaculture; Technique and non-technique

aspects

Introduction

Aquaculture has a long history of more than 2500

years, with its beginnings in China at about 500 B.C.1). Fish culture was practised without much attention until

the late 1960s, when major breakthroughs were

achieved in the artificial propagation of Chinese carps

(grass carp, Ctenopharyngodon idellus, and silver carp, Hypopthalmichthys molitrix), grass prawn, Peneaus mon

-odon, gray mullet, Mugil cephalus, and milkfish, Chanos

chanos, that provided a solid foundation for the artificial

propagation of other finfish and crustaceans2-6). Since then, aquaculture has played an important role in food

production. Contribution from aquaculture to the total fisheries production in the world continuously increased

from 14% in the middle of the 1980s to 27.6% at the end

of the 1990s7) (Fig.1).

As the 21st century approaches, aquaculture is con

-fronted with major challenges to produce more aquatic

foods, reduce production cost, minimize resource use, and conserve the environment. Furthermore, constraints

still persist in the industry brought about by the rapid

aquaculture development that happened in just three

decades. The task ahead does not seem easy.

Nevertheless, the prospects for aquaculture at least for

the coming century are bright and promising.This paper discusses the immediate challenges con-

*1Taiwan Fisheries Research Institute, 199 Hou-Ih Road, Keelung 202, Taiwan.

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274 I. C. Liao

fronting aquaculture in the 21st century. Recommen

- dations that encompass both technique and non

-technique aspects are provided. Aquaculture prospects

in the coming century are also included.

The Challenges

The human population continues to increase, especial

-ly in low-income countries. It is estimated that the popu

-lation will reach nine billion in the 2050s, with Asians

comprising nearly 60% of the total and 90% living in less

developed regions8). Although the total number of

undernourished people in the world slightly decreased

from 917 million to 839 million from 1970 to 1990, and is

projected to decrease further to 680 million in 2010, mal-nutrition would still be a major problem particularly in

the northern and eastern regions of Africa and in South

Asia9) (Fig.2).

It may be difficult to make exact predictions for the

next century. Nevertheless, it can be safe to say that the

huge human population will need more food to survive.

People rely on aquatic animals as a major protein source,

obtaining an estimated 15-20% of their protein require

- ment from fish and other aquatic organisms10).In the last five years, human consumption of aquatic foods and

the world population have comparatively increased8,10)

(Fig.3). With the leveling off and unlikely increase of capture fisheries production10), the whole world expects

aquaculture to provide for the increasing demand of

aquatic foods and other potential non-food products in

the 21st century.

Pressed with the challenge to produce more aquatic

foods, aquaculture is further facing the task for it to be

carried out with minimum use of available resources and

in harmony with the environment. To sustain the aqua-

culture industry, economic gain should still be possible

despite many limitations imposed on the industry.

Current constraints have to be resolved for aquaculture

to move forward in the coming century.

Meeting the Challenges

Two general approaches may be adapted to increase

the current aquaculture production level. These

approaches are divided into technique and non-technique

aspects.

Technique Aspects

1. Continuation of current researches

Aquaculture technologies have already advanced con

-siderably in the last three decades. Previous research

efforts have led to the development of artificial propaga

-tion techniques in a number of aquatic organisms1). In

contrast, aside from developing breeding techniques of

new potential target culture species, current researches

are directed to more specific problems. They are aimed

to further improve production efficiency while at the

same time minimizing resource use and restricting the

impacts on the environment. The most critical studies

are those that deal with disease problems, feed develop

- ment, and live foods for larviculture. These studies have

to be vigorously supported and continued.

Diseases in cultured finfish and crustaceans are major

Fig.1. World fisheries production7).*World production of capture fisheries

, excluding aquatic mammals and plants.

**World aquaculture production, excluding aquatic plants.

Fig.2. Estimates and projections of the incidence of chronic malnutrition in developing countries9).

Fig.3. World population8) and human consumption of aquatic

foods10).

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Aquaculture Development: Challenges for the 21st Century 275

production impediments at present. Novel methods, such as recombinant vaccines, are being tested to over

-come disease problems11). Administering immunostimu

-lants is another possible method to prevent future dis

-ease outbreaks12-13). In both cases, however, success has

been limited by the lack of understanding of the mecha

- nisms of immune response in finfish and shellfish.

Improvement of the knowledge on finfish and shell

- fish immune system may help improve vaccine tech

- nology or immunostimulant application in the future. Transgenic technology is another promising tool in

disease prevention. Strains resistant to specific viral and bacterial diseases are recently being developed14).

Artificial feeds for cultured finfish and crustaceans are

primarily made from fishmeal and this practice com

- petes with the target consumers that aquaculture is sup

- posed to nourish15). Alternative feed ingredients, or fish- meal replacers, are being identified and developed16).

Various feed technology and biotechnology methods are

being employed to develop feeds with alternative protein

sources for carnivorous fish species. The physical prop

- erties of artificial feeds are as important as their nutri

-tional content. Artificial feeds must be nonpolluting and

cost-effective. Current research on artificial feeds must

be adequately supported to improve feed quality, cost

- effectiveness and ingredient composition.

Live foods are critical in finfish and crustacean larvi

- culture. Artemia is one such important live food17). At

present, the global supply of Artemia is unpredictable (Table 1) and quality problems in terms of hatching and nutritional content persist from the available sources18).

It is, therefore, necessary to find alternatives to Artemia

or to develop pond culture techniques that would ensure Artemia supply of consistent quantity and quality. The

current situation of Artemia supply is an example of a

crucial factor that would affect the sustainability of the

aquaculture industry in the next century. Situations like

this deserve long-term solutions and must never be

ignored.

2. Biotechnology application

Controlling reproduction, enhancing growth rate,

improving disease resistance and survival are some of

the potential benefits that aquaculture can gain through

biotechnology application14). Current biotechnology

researches are classified into two categories: convention

- al and advanced. Conventional biotechnology includes

reproduction manipulation using hormones, monosex

culture, gamete and embryo cryopreservation, chromo

-some manipulation, and cell culture. Advanced biotech

- nology covers the production of transgenic aquatic ani

- mals as well as the development of diagnostic kits and

vaccines for viral and bacterial diseases.

Precautionary measures in developing advanced

biotechnologies, such as environmental impact assess-

Table 1. Harvests* of raw wet Artemia cysts from Great Salt

Lake, Utah, USA, during the past decade

18)* Moratorium installed by Utah Division of Wildlife Resources .

ment, must be conducted before they can be applied on

commercial scale. For instance, transgenic technology is

perceived by many to dramatically increase food produc-tion. However, it also infuses the greatest fear in the

minds of the public because it is new, inadequately

understood, and environmental risk data are lacking19).

Comprehensive evaluation of technologies that involve

genetic manipulation is essential to ensure food safety and to prevent risks to the environment.

3. Aquaculture science innovation

Continuous innovation of aquaculture science is the

most rational approach for aquaculture development in

the coming century. As stated earlier, it may be hard to

predict what will happen in the next one hundred years, but one thing is certain-the huge human population will

need more food. Demand for nutritious, healthy yet gen- erally inexpensive food will continue to rise and aquatic

foods will fill this necessity. Improvement of production

technologies, optimization of available resources, utiliza

-tion of new aquatic organisms, and development of

value-added products are some of the needed innova

-tions to meet the demand for more aquatic foods.

Non-technique Aspects

Non-technical aspects must complement the tech

- nique aspects to bolster aquaculture production in the

coming century. Subsequently, environmental concerns

can be more effectively addressed. Three specific

approaches are necessary to realize this objective.

1. Comprehensive regulation

Government policies would be critical for further

aquaculture development15). Comprehensive laws and

regulations must be formulated and implemented to pro

-tect the environment, to manage production and market

-ing, to safeguard public health, and to provide necessary

legal or financial support to aquafarmers. All aquaculture

products should meet the standard included in Hazard Analysis and Critical Control Point (HACCP). Licenses,

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276 I. C. Liao

permits, and certifications must be obtained for new aquaculture ventures. Existing farms must also be evaluated to determine if they meet the regulations.

Economic incentives or disincentives may be imposed to

encourage those in the industry to uphold the laws and regulations. The laws and regulations may be reviewed

at regular intervals and modified depending on prevail

-ing conditions.

The Norwegian salmon aquaculture is perhaps the

best example showing that regulations are necessary to

make the industry profitable, competitive and sustain

-able. The Norwegian aquafarmers themselves have been

actively involved in the process of formulating the regu

-lations. The government agencies have also been very

responsive to the needs of the farmers and the aquacul

-ture industry in general. Their cooperation has made the

implementation of the regulations effective and success

-ful.

2. Extensive education

The general public needs to be informed and educat

-ed regarding aquaculture development and what aqua

-culture is all about. Information dissemination in

schools, festivals, and popular publications are possible links to promote the positive aspects of aquaculture and

how it can be done in harmony with the environment.

Aquafarmers and all others involved in the industry

must be taught about the concept of sustainability. Only

through effective education can everyone develop a gen

- uine concern for the industry and the environment in

general.

3. Cooperative information exchange

Exchange of information must be intensified among

scientists and between institutes to prevent research

duplication and minimize research cost. In this manner,

development of technologies may also be accelerated.

With the aid of very fast changing information technolo

- gy, collaborations will be easily facilitated in the coming century. Priority should be given to the sharing of avail

-able knowledge that at present are not well disseminat

-ed. For instance, aquaculture research in Japan is very

advanced and covers a wide variety of species. However,

most of their data and results are published in Japanese

language. Very few people outside Japan can learn from

such valuable information. Therefore, translations are

needed in languages that are more widely understood.

Prospects

The future demand for aquatic foods will be deter

- mined basically by the number of consumers, their eat

-ing habits and economic conditions, as well as the price

of the different commodities10). Based on this projection,

aquaculture will have to supply two distinct groups of

consumers in the 21st century: one is the low-income

group and the other is the affluent or economically advanced group. Population growth is much higher in

the low-income group and they would require a substan

-tial quantity of affordable, inexpensive, and nutritious

aquatic foods. On the other hand, the affluent con

-sumers would be quite selective and may choose aquatic

foods based on their specific preferences. The availability

of resources for aquaculture development in the coming

century will be critical. In general, new strategies may

be adapted to meet the demands of the two groups of

consumers given the limited available resources. The

strategies include indoor/outdoor super-intensive recir

-culting culture system, sea cage aquaculture, deep

ocean water utilization, subsurface fish aggregating

device, artificial fertilization of the open sea, species diversification and domestication, stock enhancement

and sea ranching, and development of value-added prod

- ucts.

Indoor/outdoor super-intensive recirculating culture

systems would allow production at high densities using

minimum resources especially water. Sea cage aquacul

-ture is one way of increasing the number species for cul

-ture. At present, only 3.8% of cultured finfish come from the marine environment7). Deep ocean water is free from

contamination and is rich in dissolved inorganic nutri

-ents. Several industries have made use of it and one of

them is aquaculture20). Japan and Hawaii have already

invested for industrial use of deep ocean water and are

utilizing this kind of resource in aquaculture. Extraction

of deep ocean water, however, should be properly regu-lated to prevent any unforeseeable environmental conse

- quences. Subsurface fish aggregating device coupled with artificial fertilization of the open sea can be done to

improve productivity. Species diversification and domes-tication would allow more flexibility in production and

also increase species variety21,22). Species with aquacul

-t ure potential in the coming several decades are listed in

Table 2. Stock enhancement and sea ranching are indi

-rect methods of increasing fisheries production23).

Development of value-added products can be an effective

marketing strategy. It should be stressed again that all

of these new strategies must be accompanied with

appropriate measures, such as environment impact

assessment and government regulations, to avoid any

damage to the environment.

For economic sustainability, the aquaculture industry

will have to consider methods to reduce production cost.

Automation and mechanization of production are possi

-ble ways to keep the production cost at minimum and to

ensure product quality. The Norwegian salmon aquacul

-ture is again an excellent example in this respect.

Automated systems significantly reduced their produc

-tion and post-harvest processing cost which made

Norwegian salmon highly competitive in the world mar-

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Aquaculture Development: Challenges for the 21st Century 277

Table 2. Candidate finfish species for commercial culture

ket.

The general public should keep an open mind to

new approaches in aquaculture development. Given

enough research efforts, what seems impossible may

actually materialize. For instance, many previously

thought that tuna would be very difficult to breed in cap-

tivity, especially in land-based system, because they

require natural ocean water environment. Just recently

in Japan, the bluefin tuna, Thunnus thynnus, has sponta

- neously spawned successively in the aquarium by means

of photoperiod manipulation24). Fertilized eggs of the

tuna were obtained and hatching occurred. This event

opens a wide area for more research work on captive

breeding of other large pelagic species. Domestication

in particular can be possible since the offspring have

been produced under captive conditions. As another

example, eel larval rearing remains to be a mystery at

present. However, research work in Japan has already extended larval survival to 253 days25). Work in this

species appears to progress but at a very slow pace.

Nevertheless, small amount of information is also being

accumulated. With continuous research work, the mys

-tery surrounding the eel can possibly be unveiled in the

early part of the coming century. Introduction of exotic

species can be adapted to enhance local aquaculture

species diversity. As long as meticulous studies are con

- ducted, benefits can be derived from introduction of

exotic species. Production of suitable hybrids is another

area that needs to be explored. This approach can be

considered a conventional method compared with trans

- genic technology, but specific beneficial characteristics

can also be attained through this method.

Conclusion

The immediate aquaculture goal in the coming centu

-ry is to provide a sufficient quantity and quality of aquat

-ic foods for the increasing human population. This goal

has to be met without further pressure on the diminish

-ing resources and without harming the environment.

Current research efforts are already directed to attain

these objectives. With continuous research, innovations,

education, international cooperation, and appropriate

regulations, the expectations from aquaculture of con

-tributing to food security in the next century are achiev

- able. However, concepts must be renewed among the

general public so that priority is given to the most urgent need, which in the case of the coming century, is

to be able to feed the people first. Developing countries,

for instance, should choose species that are less costly

to culture instead of the fancy types that only very few

can afford. Milkfish and tilapia are relatively economical

to culture and must be the priority aquaculture species in developing countries. On the other hand, those in the

affluent countries should also minimize their appetite for

luxurious aquatic products. It should not be forgotten

that there is only one planet called Earth and its resources are not infinite. Human beings should get sat

-isfied at some point to preserve this only inhabitable

place available for us in the universe, as far as we know.

References

1) Liao,I. C.(1992): Aquaculture in Asia: status, constraints,

strategies, and prospects, in“Aquaculture in Asia”(ed. By

I. C. Liao, C. Z. Shyu, and N. H. Chao), Asian Productivity

Organization, Tokyo, and Taiwan Fisheries Research

Institute, Taiwan, pp.13-28.

2) Liu, C. K. (1963): Experiments on the artificial propagation of pond reared grass carp, Ctenopharyngodon idellus. China Fish. Mon., 129, 2-4 (in Chinese).

3) Liu, C. K. (1964): Experiments on the artificial propagation of pond reared grass carp, Ctenopharyngodon idellus, and silver carp, Hypophthalmichthys molitrix, Bull. Taiwan Fish. Res. Inst., 9, 59-70 (in Chinese).

4) Tang, Y. A., C. K. Liu, and Y. W. Hwang (1963): Preliminary result on injection of pituitary hormone to induce spawning of Chinese carps. China Fish. Mon., 129, 5-9 (in Chinese).

5) Lin, S. Y. (1965): Induced spawning of Chinese carps by pituitary injection in Taiwan. Jt. Comm. Rural Reconstr. Fish. Ser., 5,1-31.

6) Liao, I. C. (1991): Aquaculture: the Taiwanese experience. Bulletin of the Institute of Zoology Academia Sinica

(41)

278 I. C. Liao

Monograph, 16,1-36.7) FAO (1999): Aquaculture production statistics 1988-1997. FAO

Fisheries Circular No.815, Revision 11.8) UN Population Division (1999): The world at six billion.

Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. ESA/P/WP 154.

9) FAO (1996): Food, agriculture and food security: develop- ments since the World Food Conference and Prospects.

Technical Background Documents, Vol.1. World Food Summit Conference. 13-17 November 1996, Rome, Italy.

10) FAO (1999): The state of world fisheries and aquaculture 1998. FAO, Rome, Italy.

11) Lorenzen, N. (1999): Recombinant vaccines: experimental and applied aspects. Fish Shellfish Immunol., 9(4), 361-365.

12) Siwicki, A. K., M. Morand, E. Terech-Majewska, W. Niemczuk, K. Kazun, and E. Glabski (1998): Influence of immunostimulants on the effectiveness of vaccines in fish: in vitro and in vivo study. J. Appl. Ichthyol., 14(3-4), 225-227.

13) Sakai, M. (1999): Current research status of fish immunos-timulants. Aquaculture, 172(1-2), 63-92.

14) Liao, I. C. and N.H. Chao (1997): Developments in aqua- culture biotechnology in Taiwan. J. Marine Biotechnol. 5,

16-23.15) Liao, I.C.(1998): Toward a sustainable aquaculture deve

l-o pment, in“Improving Management of Aquaculture in

Asia”(ed. by M. Hotta), Asian Productivity Organization,

Tokyo, pp.62-77.

16) Tacon, A. G. J. (1994): Feed ingredients for carnivorous fish species alternatives to fishmeal and other fishery resources. FAO Fisheries Circular No. 881, Rome, Italy, 35 p.

17) Leger, P. and P. Sorgeloos (1992): Optimized feeding

regimes in shrimp hatcheries, in“Marine Shrimp

Culture: Principles and Practices”(ed. by A. W. Fast and

L.J. Lester), Elsevier Science Publishers, New York, pp.

225-244.

18) Lavens, P. and P. Sorgeloos (2000): The history, present status and prospects of the availability of Artemia cysts for aquaculture. Aquaculture (in press).

19) Dunham, R. A. (1999): Utilization of transgenic fish in developing countries: potential benefits and risks. J. World Aquacult. Soc., 30(1), 1-11.

20) Loupe, D. (1991): The Food Factor. Sea Frontiers, March-April 1991. pp. 21-26.

21) Liao, I. C.: The status of finfish diversification in Asian aquaculture. Proceedings of Seminar on Mediterranean Marine Aquaculture Finfish Species Diversification, 24-27 May, 1999. IAMZ, Zaragoza, Spain (in press).

22) Liao, I. C. and Y. S. Huang: Methodological approach used for the domestication of potential candidate for aquaculture. Proceedings of Seminar on Mediterranean Marine Aquaculture Finfish Species Diversification, 24-27 May, 1999. IAMZ, Zaragoza, Spain (in press).

23) Liao, I. C.(1999): How can stock enhancement and sea

ranching help sustain and increase coastal fisheries, in

“ Stock Enhancement and Sea Ranching”(ed. by B. R.

Howell, E. Moksness, and T. Svasand),Blackwell Science,

London, pp.132-149.

24) The Nihon Keizai Shimbun (1999). August 17.25) Tanaka, H. (1999): Early life cycle of artificially-hatched

eel. Abstracts of the Symposium on Conservation Strategy and Management Status of Eel Resources. Ocean Research Institute, University of Tokyo, 16 p.

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