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Vertebrates
Fisheries and fish prices in Hong Kong
by William Cheung
There is no doubt that fishery resources in Hong Kong waters have greatly declined over the last century, with an overall decrease in fishery catches and a shift from large predatory species to small fishes and invertebrates. Changes in the local fishery stocks and marine ecosystem have been variously discussed. However, it may also be interesting to also take a look at the changes in prices of local fishery landings. Do they show any particular trend? Is there any relationship between the prices and different components of the fishery?
To review trends in the prices of local landings, average annual wholesale prices of 34 groups of organisms marketed through the Fish Marketing Organization (FMO) responsible for the management of all local government fish wholesale markets, between 1965 to 2000, were compiled. The 34 groups of organisms were divided into three categories: small finfish (fish with an asymptotic length < or equal 60 cm), large finfish (fish with an asymptotic length > 60 cm) and invertebrates. To show any trend in changes in the annual average wholesale price for each group more clearly, a running average of the prices for sets of three consecutive years were calculated and plotted along with the annual Consumer Price Indices (CPIs) of Hong Kong (Census and Statistics Department, 1975-2000) (Fig. 1). The CPIs are used as a rough indicator of the local economic situation (an increase in CPI reflects inflation and vice versa).
Some trends in the prices of the three categories of landings were observed. Firstly, since the mid-1970s, wholesale prices of large finfish and invertebrates have increased rapidly and more rapidly than the economy. Increase in prices of large finfish slowed down around 1980 while the price of invertebrates continued to rise. Both around levelled off after 1990. The price of small finfish increased slowly and remained low throughout recorded years.
The observed changes in landing prices may be related to local fisheries. Though the inshore waters have been depleted of large fishes and suffer from over-exploitation, the total value of the fisheries in Hong Kong waters have evidently been sustained by the high value, and relatively more stable catches, of invertebrates. The high price of invertebrates might also be the major reason for the dramatic expansion of the shrimp trawling sectors in Hong Kong, despite an overall decrease in local resource abundance since the 1960s (Cheung, in prep.). Pauly (1994) also suggested that though fish populations were at densities lower than would be economically sustainable if only the fish were taken, trawling was effectively subsidized by the high value of the shrimp.
The high value of the shrimp trawl fishery may, in turn, lead to a more serious degradation of the local marine ecosystem. Shrimp trawling can be considered as a destructive fishing method because a small cod-end mesh size is used and the direct contact of the trawl-net with the sea bottom, by which it catches small fishes unselectively, damages and disturbs sea bottom habitat at the same time. Conventional single species bio-economic theory predicts that fishing become uneconomical and fishing effort eventually reduces to an economically ‘optimal’ level as fishery resources become depleted (Hilborn and Walters, 1992). Nevertheless, when an ecosystem perspective is adopted, the reduction in large predatory species by fishing reduces predation and releases their prey which include small fishes and invertebrates. Together with the generally high resistance to exploitation because of their fast turnover rate, the shrimp trawl fishery is being sustained in a depleted ecosystem.
To restore the Hong Kong marine ecosystem, reduction of fishing effort of trawlers, especially the shrimp trawlers, should be implemented and economic considerations would be a major factor in the practical implementation of management.
There are a few underlying assumptions in the above data analysis. Firstly, the FMO price record is assumed to reflect the average price of the whole fish market in Hong Kong. Cheung (in prep.), however, showed that there was a continuous decrease in the proportion of Hong Kong fishermen landing their catch in the FMO since the 1950s. Therefore, care has to be taken when studying the changes in prices of landings in recent years. Secondly, the FMO record only represents prices of "dead" (frozen or preserved) food fishes; since live fishes are not treated as food under the present legislation their prices and landings are not recorded! Thirdly, only the general economic status of the society, represented by the CPIs, is roughly taken as a reference for the fish prices. Other factors affecting fish prices such as festivals and holidays are not taken in account here.
Under the above assumptions, though a precise and thorough analysis is not possible, the results provide a general insight into how local fish prices and fishery can be are related and what may be the driving factor(s) enabling fishing to continue in a depleted fishery.
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Fig. 1. Average landed value of small finfish (Sm. FF), large finfish (Lg. FF) and invertebrates (Invert.) recorded by the Hong Kong Fish Marketing Organization (FMO) from 1965 to 2000. The Consumer Price Index (CPI) of Hong Kong (Census and Statistics Department, 1975-2000) was also plotted to serve as a reference for the general economic status of Hong Kong society.
Bibliography
Census and Statistics Department (1975-2000). Hong Kong Annual Digest of Statistics. Census and Statistics Department, Hong Kong.
Cheung, W. L. in prep. Changes in Hong Kong’s Capture Fisheries During the 20th Century and Reconstruction of the Marine Ecosystem of Local Inshore Waters in the 1950s. M.Phil. Thesis. The University of Hong Kong, Hong Kong.
Pauly D. (1994). On Malthusian overfishing. Page 112-117 In: On the Sex of Fish and Gender of Scientists. Chapman and Hall, London.
Hilborn, R. and Walters, C. J. (1992). Quantitative Fisheries Stock Assessment: Choice, Dynamics and Uncertainty. Chapman and Hall, New York.
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