Krishen Rana, Maurizio Perotti,

Sara Montanaro and Anton Immink

Fisheries Information, Data and Statistics Unit


China’s underestimated national

aquaculture production and global

contribution addressed and

rectified by FAO




Figure 1. Increase in reported Chinese production of the sum of three shellfish species and unclassfied molluscs resulting from converting meat to whole live weight

The Fisheries Information, Data and Statistics Unit(FIDI) of the Food and Agricultural Organization (FAO) has been systematically collecting analysing and disseminating data on global aquaculture production by weight and value (US$) since 1984. In parallel, the mechanisms for collecting data and the coverage and quality of data on production from aquaculture provided by countries to FAO have been constantly under review with the aim of improving their accuracy, quality, scope and relevance to future national and global needs as well as ensuring reporting according to international norms and standards.

China continues to dominate world aquaculture production. Her share of global aquaculture (including plants) increased from 37.7% or 3.8 million tonnes in 1984 to 67.8% or 23.1 million tonnes in 1996. Therefore any changes in Chinese aquaculture development or reporting may greatly influence global fisheries production. It has recently come to light that China has been reporting production statistics of three molluscs species: the blood cockle, Japanese carpet shell, Pacific cupped oyster and unclassified marine molluscs, to FAO as shelled or shucked weight. Consequently, to date, the contribution of:

•shellfish (molluscs and crustaceans) to Chinese and global aquaculture,

•Chinese aquaculture to their national fisheries landings,

•Chinese aquaculture to global aquaculture and

•Global aquaculture to world fisheries landings have been understated. This year FAO, in consultation with the Chinese

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Ministry of Agriculture, adjusted Chinese and global aquaculture production statistics and reflected these in its databases, time series and subsequent analysis.

While acknowledging that meat or shucked weight may be appropriate units for expressing production, the standard practice of FAO and other international fishery organisations is to report aquatic production as "nominal catch" which is the live weight equivalent. When the production of species reported to FAO is known to be given as dry or shelled weight, appropriate conversion factors are applied to convert these to live weight equivalent to ensure international comparability. In the case of China, the FAO statistics for three shellfish species: the blood cockle, Japanese carpet shell, Pacific cupped oyster and unclassified marine molluscs, were adjusted from shucked to live weight equivalents using conversion factors of 1.35, 2.13, 6.11 and 2.13, respectively, provided by the Chinese Ministry of Agriculture.

The implication of converting reported production from meat to live weight for Chinese production between 1984 and 1996 is shown in Figure 1. During this period the total Chinese production (live weight) statistics of these shellfish increased from 347 000 tonnes to 4.70 million tonnes. Therefore previous reporting of these shellfish by FAO underestimated their production by 255 000 tonnes or 276% in 1984 and 3.16 million tonnes or by 205% in 1996. In view of the rapid increase in their production after 1990 (see Figure 1) the impact of these changes are only highlighted here for 1990 to 1996. The exponential increase between 1990 and 1996 is due to a combination of the rapid expansion rate in the culture of Japanese carpet shell and particularly the Pacific oyster (Figure 1). Between 1984 and 1996 these two species accounted for 71-85% of total shellfish production.

Following the conversion, the reported production statistics of Chinese shellfish (molluscs and crustaceans) increased from 1.32 to 2.0 million tonnes or by 52% in 1990 and from 3.49 to 6.64 million tonnes

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or by 90.5% in 1996 (Figure 2). The contribution of Chinese shellfish production to global cultured shellfish production increased by 18% in 1990 and by 49% in 1996 (Figure 2). The increase in the quantity of adjusted shellfish production also greatly changed the statistics on estimated total Chinese aquacultural output. The total reported aquaculture production, including plants, for China increased from 7.5 to 8.2 million tonnes or by 9% in 1990 and from 20.0 to 23.1 million tonnes or by 15.8% in 1996. The new higher reported production statistics also altered the contribution of cultured fin- and shell-fish to Chinese fin- and shell-fish landings (Figure 3). Between 1990 and 1996 their contribution to national fin-and shell-fish landings increased by 1.5 and 3.8%, respectively. At the global level, the statistics on China’s aquacultural contribution to world aquaculture production increased. For 1990 its contribution rose from 46.5 to 48.7%, and in 1996 from 64.5 to 67.8%. Similarly, the contribution of global cultured finfish and shell-fish to total world fin- and shell-fish fisheries increased by 0.6% in 1990 and 2.1% in 1996 to 13.3 and 21.8%, respectively. Finally, the contribution of global aquaculture production, including plants, to world aquatic production increased by 0.6% in 1990 and by 1.8%, 1996, to 16 and 26%, respectively.

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