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Relationship of Freshwater Aquaculture Production to Renewable Freshwater Resources

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Journal of Applied Aquaculture, 24(2), 2012-05-25

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1

Relationship of Freshwater Aquaculture Production to Renewable Freshwater Resources

Claude E. Boyd* & Li Li

Department of Fisheries and Allied Aquacultures, Auburn University, Alabama 36849 USA

Randall Brummett

World Bank, 1818 H Street NW, Washington, DC 20433 USA

Keywords: freshwater aquaculture production, water use in aquaculture, aquaculture and

environment, water resources

Running Head: Freshwater use in aquaculture

*Corresponding author. E-mail: boydce1@auburn.edu

2

ABSTRACT

At the country-level, freshwater aquaculture production was correlated (P < 0.05) with area,

renewable freshwater, and population increased – the strongest tendency was with population.

Intensity of freshwater use for aquaculture in 172 countries was estimated by dividing freshwater

aquaculture production (tonne/yr) by total natural renewable freshwater (km3/yr). The

freshwater aquaculture production:renewable freshwater ratio (AFR) varied from 0 to 15,000

tonne/km3. Country-level AFRs were assigned to classes: no freshwater aquaculture, (n = 35);

low, < 100 tonne/km3 (n = 80); medium, 100-1,000 tonne/km

3 (n = 45); high, > 1,000 tonne/km

3

(n = 12). Most renewable freshwater is in countries with no freshwater aquaculture or low AFR;

countries with high AFR contain 11.1% of global renewable freshwater. By FAO region, AFR

values were: Oceania, 1.56 tonne/km3; Latin America and Caribbean, 31.1 tonne/km

3; North

America, 50.0 tonne/km3; Europe, 68.7 tonne/km

3; Africa, 84.1 tonne/km

3; Asia, 2,409

tonne/km3. Renewable freshwater appears adequate for considerable expansion of aquaculture –

especially outside Asia.

3

INTRODUCTION

The urgent need to increase food production to nourish a growing world population is widely

acknowledged. Approximately 15% of global animal protein supply is derived from fish and

shellfish. The current population of 6.91 billion consumes an estimated 117.8 million tonne/yr of

fisheries products (FAO, 2010). Capture fisheries apparently have reached or possibly exceeded

a sustainable limit, while world population is expected to increase by about 32% to 9.15 billion

by 2050 (World Bank 2010). Aquaculture currently contributes nearly 50% of current production

and of this freshwater aquaculture accounts for 35.0 million tonne/yr or 63.5% (FAO 2010).

With no change in per capita consumption, a population of 9.15 billion will demand about 156

million tonne/yr of fisheries products of which freshwater aquaculture will need to contribute

some 54 million tonne/yr.

However, resource use efficiency is an issue for aquaculture (Pillay, 2004; Tacon et al., 2006;

Boyd et al., 2007; Tucker and Hargreaves, 2008). With respect to water, Boyd (2005) presented

procedures for estimating total and consumptive water use by aquaculture facilities. Verdegem

and Bosma (2009) estimated that total water use in freshwater aquaculture averages about 16.9

m3/kg production representing 429 km

3/yr globally. This is between 1 and 4% of the usual

estimates of the world’s renewable freshwater supply.

There is considerable scope for obtaining more production per unit of water through

intensification (Boyd, 2005; The World Bank, 2006; Verdegem and Bosma, 2009), but this will

inevitably involve trade-offs with other natural resource uses. In any case, little information has

4

been presented to date on the extent to which freshwater water supplies are a constraint to the

expansion of aquaculture. The present study evaluates the current relationship between

freshwater aquaculture production and renewable freshwater for different countries and attempts

to infer the degree to which aquaculture will be limited by availability of freshwater in the future.

MATERIALS AND METHODS

Estimates of annual total natural renewable freshwater: the sum of surface runoff within a

country, all surface water flowing into the country from neighboring countries and renewable

groundwater, were obtained from Gleick (2009) for 172 of the world’s 224 countries. In most

countries flows of both surface water and groundwater enter from and exit to neighboring

countries but the amount of these gains and losses seldom balances at the country level. In order

to avoid the problem of multiple accounting that would result from summing country-level data

for a region, total internal natural renewable freshwater estimates for the FAO regions were

obtained from the FAO Aquastat Program website (www.fao.org/nr/water/aquastat/dbase/index.stm).

The sum of the estimates of total internal natural renewable freshwater for the FAO regions of

the world is 43,764 m3/yr – quite similar to the traditional estimate of 39,700 m

3/yr based on the

difference between precipitation falling on land masses and evapotranspiration from land masses

(Baumgartner and Reichel 1975).

Freshwater aquaculture production data were obtained for these countries from FAO fisheries

statistics (Fishstat 2011). An indicator of the intensity of water use for freshwater aquaculture

was estimated for each country using the following equation:

5

where AFR is the freshwater aquaculture production to renewable freshwater ratio (tonne/km3),

AP is freshwater aquaculture production in 2008 (tonne/yr) and RF is the total renewable

freshwater (km3/yr) according to Gleick (2009). The AFR also was estimated for continent and

GLOBAL levels by combining country data accordingly.

Scatter diagrams were used to depict relationships at the country level among total renewable

freshwater, land area (http://data.worldbank.org/), population (http://data.worldbank.org/), and

freshwater aquaculture production. The range of these variables was great; log10 transformation

was used to simplify graphical presentation.

RESULTS AND DISCUSSION

Freshwater is not uniformly distributed globally and differences in the availability of freshwater

are one reason that population also is not uniformly distributed. It is therefore not surprising that

the amounts of renewable freshwater and country surface areas were positively correlated (R2 =

0.557) (Fig. 1). Positive correlations were also found between country surface area, amount of

renewable freshwater and population (Fig. 1) (R2 = 0.570 and 0.421, respectively). In short, large

countries tend to have more renewable freshwater and larger populations than smaller countries.

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Freshwater aquaculture production was not highly correlated with either renewable freshwater

(R2 = 0.271) or area (R

2 = 0.123) (Fig. 1). A higher correlation (R

2 = 0.513) was found between

population and aquaculture production (Fig. 1). This relationship seems logical because a

country with a greater population will require proportionally more food than a country of smaller

population.

There are no doubt interactions among the relationships shown in Fig. 1, and other factors.

Availability of land suitable for aquaculture, climate, political stability, government policy,

cultural food preferences and fish market integration affect a country’s aquacultural production.

Nevertheless, a country’s population size seems to be a major variable influencing the amount of

aquaculture. This is likely a key reason why heavily populated Asian countries have such a large

amount of aquaculture production compared to other regions (Table 1).

The world average AFR of 721 tonne/km3 is influenced greatly by the high AFR (2,409

tonne/km3) for Asia, and particularly by the AFR of 7,344 tonne/km

3 for China (Table 1).

Removing China from the calculation reduces AFR for Asia to 957 tonne/km3 and for the world

to 263 tonne/km3. The global AFR excluding Asia is only 48.9 tonne/km

3. Africa, North

America, and Europe have fairly similar AFRs – these three continents have a combined AFR of

65.0 tonne/km3. Oceania, Latin America and Caribbean have lower AFRs – their combined AFR

is 29.1 tonne/km3.

The AFR values were placed in four classes as follows: no freshwater aquaculture, 35 countries;

low, 80 countries with AFR < 100 tonne/km3; medium, 45 countries with AFR > 100 but < 1000

7

tonne/km3; high, 12 countries with AFR > 1,000 tonne/km

3 (Tables 2 and 3). Africa had the

most countries with no aquaculture, while Europe had the most countries with low AFR. The

most countries with medium and high AFR were in Asia. The averages and standard deviations

for AFRs by class were: low, 22.4 26.6 tonne/km3; medium, 291.8 203.8 tonne/km

3; high,

4,154.8 4,619.7 tonne/km3. Individual country AFRs were heavily skewed to the left (lower

AFR) indicating considerable scope for expansion within the existing water resource base (Fig.

2).

Of the 172 countries for which renewable freshwater data were available, 35 reported no

reported freshwater aquaculture to FAO. For the 137 countries reporting freshwater aquaculture

production, AFR ranged from < 1 tonne/km3 to 7,344 tonne/km

3 in China, 11,324 tonne/m

3 in

Israel and 15,000 tonne/km3 in Kuwait. The latter two of these are small, water-restricted

countries and two others in the high AFR class are large, water-restricted countries (Egypt and

Iran). The amounts of total natural renewable freshwater represented by each AFR class were: no

aquaculture, 1,909 km3; low, 34,097 km

3; medium, 12,926 km

3; high, 6,356 km

3. Thus, about 65%

of the world’s renewable freshwater is in countries that have no freshwater aquaculture or fall

into the low AFR class.

The projected freshwater aquaculture production needed to maintain current world consumption

of fisheries products was estimated to be about 55.1 million tonne/yr by 2050. This level of

production equates to a world AFR of 1,259 tonne/km3. Tripling production in the low-income

and food insecure countries of Latin America and Africa would result in AFR in these regions

8

increasing from 31.1 tonne/km3 to 93 tonne/km

3 and from 84.1 tonne/km

3 to 252 tonne/km

3,

respectively, still below the theoretical technical maxima measured in high AFR countries.

From our analysis, overall availability of freshwater at country and regional levels is not a

constraint to meeting future global fish and shellfish demand by increasing aquaculture. The

main negative environmental issues related to high freshwater aquaculture production at the

country level are competition with other water uses and water pollution resulting from

aquaculture (Boyd et al., 2007). Based on regional studies of individual aquaculture industries

such as channel catfish, (Ictalurus punctatus), in the southeastern United States (Boyd et al.,

2000; Tucker and Hargreaves, 2008), and Pangasius catfish in Vietnam (Bosma et al., 2009),

aquaculture appears to be a relatively small contributor to water pollution and water use conflicts

as compared to some other activities.

AFR roughly approximates aquaculture production system intensity and increasing AFR may

thus be the most environmentally affordable means of raising overall output within the existing

freshwater resource base. Technology to reduce water consumption by over 60% is already

available (Verdegem & Bosma 2009). However, increasing AFR in many Asian countries, and

especially in China, would result in higher AFRs in a region where values are already much

greater than in the rest of the world and could reach levels that confront environmental, energy

and input constraints to further increases.

Eco-label certification programs are increasingly used to create market incentives for aquaculture

producers to use systems that treat the environment responsibly (Clay, 2008). Water use

9

efficiency and intensity should be considered important components of environmental

sustainability. Considering that freshwater availability overall is a major concern for 21st century

global society, AFR, which embodies these might thus serve as a useful indicator of wise water

management in aquaculture.

REFERENCES

Baumgartner, A. and E. Reichel. 1975. The world water balance. Amsterdam: Elsevier.

Bosma, R.H., C.T.T. Hanh, and J. Potting, editors. 2009. Environmental impact assessment of

the pangasius sector in the Mekong Delta. Ministry of Agriculture and Rural

Development/Department of Aquaculture, The Netherlands: Wageningen University

Boyd, C.E. 2005. Water use in aquaculture. World Aquaculture 36(3):12-15 and 70.

Boyd, C.E., C S. Tucker, A. McNevin, K. Bostick, and J. Clay. 2007. Indicators of resource use

efficiency and environmental performance in fish and crustacean aquaculture. Reviews in

Fisheries Science 15:327-360.

Boyd, C.E., J. Queiroz, J. Lee, M. Rowan, G.N. Whitis, and A. Gross. 2000. Environmental

assessment of channel catfish, Ictalurus punctatus, farming in Alabama. Journal of the

World Aquaculture Society 31:511-544.

Clay, J.W. 2008. The role of better management practices in environmental management.

Pages 55-72 in C.S. Tucker and J.A. Hargreaves, eds. Environmental best management

practices for aquaculture. Ames, IA: Wiley-Blackwell.

FAO (Food and Agriculture Organization). 2010. The state of world fisheries and aquaculture.

FAO Fisheries and Aquaculture Department, Rome, Italy.

10

FAO. 2011. FISHSTAT electronic database. Food and Agriculture Organization of the United

Nations, Rome, Italy.

Gleick, P.H. 2009. The world’s water 2008-2009. Washington, DC: Island Press.

Pillay, T.V.R. 2004. Aquaculture and the environment, 2nd

edition. Oxford, UK: Blackwell

Publishing.

Tacon, A.G.J., M.R. Hasan, and R.P. Subasinghe. 2006. Use of fishery resources as food inputs

to aquaculture development: trends and policy implications. FAO Fisheries Circular No.

1018, Food and Agriculture Organization of the United Nations, Rome, Italy.

Tucker, C.S. and J.A. Hargreaves, editors. 2008. Environmental best management practices for

aquaculture. Ames, IA: Wiley-Blackwell.

Verdegem, M.C.J. and R.H. Bosma. 2009. Water withdrawal for brackish and inland aquaculture,

and options to produce more fish in ponds with present water use. Water Policy 11

(Supplement 1):52-68.

World Bank. 2006. Aquaculture: changing the face of the waters, meeting the promise and

challenge of sustainable aquaculture. Agriculture and Rural Development, Report No.

36622-GLB, The World Bank, Washington, D.C.

World Bank. 2010. World Development Report; development and climate change. The World

Bank, Washington, DC.

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Table 1. Renewable freshwater, freshwater aquaculture production, and freshwater aquaculture

production:renewable freshwater ratio (AFR) by FAO region.

Continent

Renewable freshwater

(km3/yr)

Freshwater aquaculture

(tonne/yr)

AFR

(tonne/km3)

Asia 12,461 30,015,550 2,409

(Asia without China) 9,649 9,234,485 957

Africa 3,950 332,113 84.1

North America 6,662 333,219 50.0

Europe 6,619 454,501 68.7

Latin America and Caribbean 13,161 408,692 31.1

Oceania 911 1,424 1.56

World 43,764 31,545,499 721

(World without China) 40,952 10,764,434 263

Table 2. Number of countries (n) and associated amounts of renewable freshwater (based on sum of country-level estimates) by

FAO region and freshwater aquaculture production to renewable freshwater ratio (AFR) class. None, AFR = 0 tonne/km3; low,

AFR < 100 tonne/km3; medium, AFR = 100 to 1,000 tonne/km

3; high, AFR > 1,000 tonne/km

3.

None Low Medium High

Continent n km3 n km

3 n km

3 n km

3

Latin America and Caribbean 1 3.8 16 14,917 7 3,370 0 0

North America 0 0 2 6,369 0 0 0 0

Asia 7 199 5 441 17 7,985 9 6,247

Europe 3 210 29 7,035 14 1,096 2 22

Oceania 2 442 2 1,227 0 0 0 0

Africa 18 1,040 26 4,122 7 475 1 87

World 35 1,909 80 34,087 45 12,926 12 6,356

12

Table 3. Countries with over 50 km3/yr of renewable freshwater listed by freshwater aquaculture

production to renewable freshwater ratio (AFR) classes. The top ten freshwater aquaculture

producers are in bold font (FAO 2010).

AFR class Country

Low (< 100 tonne/km3) Angola, Cameron, Congo, Congo (DR), Cote D’Ivoire,

Gabon, Madagascar, Mali, Mozambique, South Africa,

Sudan, Zambia, Canada, Guatemala, Mexico, Nicaragua,

Panama, Argentina, Bolivia, Brazil, Chile, Colombia,

Ecuador, Guyana, Paraguay, Peru, Uruguay,

Venezuela, Cambodia, Japan, Korea (DPR), Austria,

Greece, Iceland, Netherlands, Portugal, Romania,

Slovakia, Sweden, Switzerland, United Kingdom, Russia,

Belarus, Georgia, Kazakhstan, Tajikistan, Turkmenistan,

Uzbekistan, Australia, and Papua New Guinea

Medium (100-1,000 tonne/km3) Ghana, Nigeria, Uganda, Belize, Costa Rica, Honduras,

United States, Bangladesh, Indonesia, Iraq, Korea,

Laos, Malaysia, Myanmar, Nepal, Pakistan,

Philippines, Sri Lanka, Turkey, France, Germany,

Hungary, Italy, Poland, Spain, and Ukraine

High (> 1,000 tonne/km3) Egypt, China, India, Iran, Taiwan, Thailand, and

Vietnam.

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Fig. 1. Scatter diagrams of relationships among area, total natural renewable freshwater,

population, and freshwater aquaculture production of counties.

14

Fig. 2. Frequency distribution histograms for the ratio of annual, freshwater aquaculture

production to renewable freshwater resources (AFR) for countries with low (upper),

medium (middle) and high (lower) AFR values.