Economic production from the coral reef fisheries of Jamaica and captured ecosystem values.

摘要

The production of an economic good derived from a renewable natural resource base involves the extraction of ecosystem function values as represented by the contribution made to production by the originating ecosystem. The artisanal fisheries of Jamaica is used as a case study in the examination of the characteristics of economic production processes and the development of a biophysically-based index to account for captured ecosystem values. The following is provided: (i) a description of the fisheries of Jamaica and derivation of economic production function models; (ii) a description of the socio-economic condition of the fisheries of Montego Bay Marine Park (Montego Bay, Jamaica) which serves to further illustrate the nature of artisanal fisheries in Jamaica, as well as a more traditional economic approach to resource valuation; and, (iii) the development of an index which as a proxy measure captures the biophysical values of the contributions of the natural biotic environment (the "embodied ecosystem values") to the fisheries, and an examination of the extent to which those values are proportionately reflected in monetary exchange values. In addition, contributions are made concerning: (i) the development of an economic data collection and analysis programme for Jamaica (also more widely applicable to countries of the developing tropics) which will allow for more informed decisions concerning the management of coral reef fisheries; (ii) general principles concerning the development of biophysical indices, such as indices of biodiversity, which will ultimately be used to inform government policy and management decisions; (iii) the validity of indices derived from ecosystem statistics; and, (iv) the potential for the further development of models which explicitly incorporate the contributions of ecosystems to economic production processes.; Cobb-Douglas and translog models of fishing effort are derived from catch and effort data for the years 1996 and 1997 to describe the relationships between catch and firm-level inputs as they vary by fishery within Jamaica. Data on the total catch, crew size, gear soak time, and quantity of gear used yield separate functions of effort for the use of China net, trap, hand line, palanca, speargun, and troll fishing technologies. By further accounting for the month and fishing location (i.e. north coast versus south coast), the seasonal and regional influences on catch rates are explored. Patterns of production include reduced catch rates associated with fishing the north coast shelf and a seasonal peak in catch levels during the late summer and fall. The use of production function models of effort are found to provide informative descriptions of fishery production processes, yet avoid many of the technical difficulties associated with more traditional bioeconomic approaches. The Index of Captured Ecosystem Value (ICEV) is developed from a basis in information theory relevant to an analysis of network flows in ecosystems. Technical coefficients, describing the production relationship between ICEV values and market values of catches associated with individual fishing efforts, revealed that captured ecosystem function associated with fisheries using distinct technologies (i.e. China net, trap, hand line, palanca, and speargun) were valued differently by the market. This "surplus value" appears to be rooted in the observation that certain fisheries target species which are more connected within the coral reef food web than those species typically captured by other fisheries. Consideration of the biophysical contributions of coral reef ecosystems to fisheries production reveals distortions between market and supply-side values, indicating that the role of ecosystems is not being consistently treated.