This paper puts forward a model of Pearl River Delta (PRD) fishery in the South China Sea (SCS) that integrates the ecological, social and economic costs and benefits of fisheries activities in a multidisciplinary framework. In particular, an integrated ECOST model is composed of links between an ecological model constructed by Ecopath with Ecosim (EwE) software and a region Social Accounting Matrix (SAM). Then the costs and benefits of five fishing methods are compared from economic, ecological and social three dimensions base on the ECOST model. The potential effects of fishing effort reduction on fishing communication are explored by a series of dynamic simulations for a 10-year period. Key results from prediction (2005-2015) and policy simulations illustrate that fisheries of PRE are geared toward short-term economic profits at the expense of ecological gains and the whole group of societal benefits associated with fishing. However, the status quo can be improved to better levels by reducing fishing efforts.
In China, the Pearl River is the second largest river (2200 km) in terms of water discharge, after the Yangtze. Currently, the coastal region of the Pearl River Estuary (PRE) is a significantly and quickly developing economic zone in China [
Increasingly, scientists and economists from different disciplines have begun to realize the importance of pooling their information and results into multidisciplinary studies [
The traditional bio-economic model is based on the Gordon-Schaefer model [
The second group is regional fisheries economic models, which focuses on the regional economic impacts of fishing sector. After Andrews and Rossi [
Rather than the traditional management focus on individual stocks and individual regional fishery economics, nowadays, widespread acceptance that a more integrated perspective is needed would take marine ecosystem preservation, economics and social objectives into account. In this context, the ecosystem-based fishing management (EBFM) approach has emerged as a promising approach [
This paper presents the integrated ecological-economic-social model-ECOST on the fisheries societal costs and benefits in the PRD. The ECOST model was developed by Failler and Pan [
As a result of rapid economic development in recent decades, the coastal Pearl River Delta has experienced rapid industrialization and urbanization. The high population density and rapid development of industry and agriculture have resulted in severe stress to the aquatic environment. The PRE is also an important fishing ground in the South China Sea, and it provides abundant fishery resources for the PRD. The PRE ecosystem in this study (less than 60 m depth) ranges from 112˚30'E to 115˚00'E, 21˚30'N to 23˚30'N. The PRE falls largely within the PRD Economic zone. The study area is associated with six municipal cities, including Guangzhou, Zhuhai, Zhongshan, Dongguan, Shenzhen and Jiangmen, and two special administered regions, namely, Hong Kong and Macau (
Because of the special hydrological features of the PRE, the interaction among fish species in the Pearl River are quite complex, primarily because of the large variety of species involved, and their diverse mechanisms of biological predation and habits [
Chinese fisheries policy has moved in a new direction toward the sustainable utilization of fisheries resources. Since fisheries are facing obvious risks from depleting natural resources and serious environmental pollution [
ECOST model presents a fishery assessment method that attempts to assess the social, economic and ecological
costs and benefits in a framework coupling the ecosystem to socio-economic systems. As a typical estuary ecosystem, the PRE ecosystem can be described by the interactions of species in a complex food web. Therefore, understanding the biomass stock and ecological relationships of these species is an important part of designing renewable resource policies. In this paper, the PRE ecosystem is simulated by applying an Ecopath model, which has been widely used for constructing food-web models of marine and other ecosystems [
An accounting method is applied for economic analysis of the fisheries, and a social accounting matrix (SAM) is constructed for the PRD fishing sector to examine both the linkages between the fishing industry and other industrial sectors, and their relationship with social levels from the household to the global scale. The SAM table provides a consistent database that allows for a detailed analysis of the economic structure of the PRD, and it is a useful tool for assessing the impact of fishing activities on the economy as a whole. Then we try to link the socio-economic model and the ecological model to produce an integrated ECOST model for fisheries management. And this integrated ECOST model is adopted to assess the societal benefits and costs for fisheries activities in the PRD. Finally, simulations are developed for a 10-year (2005-2015) period under five scenarios based of the 1998 Ecopath model with each scenario involving reduction of fishing effort of vessels by different métiers at annual rate of 5% from 1985 to 2015 for 30 years. The heterogeneity of fleets, such as vessel size and fishing gear types, leads to a variety of economic, social and ecological evaluation.
The ECOST model is built on Microsoft Excel 2007 version and contains several sheets, which are divided into the following three parts: data input, connection between ecological and socio-economic systems, and results output. The data input includes six sheets: macroeconomic, métier, microeconomic, economy, social and efforts. The results output includes the biomass, input and output table, multiplier, society and 10-year dynamic simulation. The connection section is an Ecopath sheet in the ECOST model describing the linkage between the socio-economic and ecological models. The results of the biomass changes, which are simulated by Ecosim model, are imported into ECOST model. Finally, fishing policy is simulated through time-series of fishing efforts, which are based on the optimal allocation of fleets among different métiers. The theoretical and mathematical backgrounds of the ECOST model are detailed elsewhere [
The Ecopath with Ecosim is applied in the ecological model to analyze the structure of trophic interaction in the ecosystem. The method and theory of Ecopath and Ecosim modeling are detailed in the EwE user guide [
lationship. Here, observed time-series catch rate data of commercial fish and fishing effort data of five fishing métiers from 1981-2005 are used to estimate the vulnerability factors which provided some empirical support to the model. A previous constructed Ecopath model [
Here, a social accounting matrix (SAM) provides a consistent database that allows a detail analysis of the eco-
No. | Group name | Trophic level | B (t∙km−2) | P/B (year−1) | Q/B (year−1) | EE | P/Q |
---|---|---|---|---|---|---|---|
1 | Benthic producers | 1.0 | 153.000 | 11.89 | - | 0.01 | - |
2 | Phytoplankton | 1.0 | 13.000 | 231 | - | 0.47 | - |
3 | Zooplankton | 2.0 | 10.400 | 32.00 | 192.00 | 0.31 | 0.167 |
4 | Jellyfish | 3.1 | 1.075 | 5.01 | 25.04 | 0.74 | 0.200 |
5 | Polychaeta | 2.0 | 0.800 | 6.75 | 22.50 | 0.89 | 0.300 |
6 | Mollusks | 2.2 | 0.700 | 3.50 | 11.70 | 0.86 | 0.299 |
7 | Echinoderms | 2.3 | 0.240 | 1.20 | 3.58 | 0.88 | 0.335 |
8 | Benthic crustaceans | 2.2 | 0.560 | 5.65 | 26.90 | 0.84 | 0.210 |
9 | Other zoobenthos | 2.6 | 1.690 | 1.00 | 9.00 | 0.74 | 0.111 |
10 | Shrimps | 2.3 | 3.08 | 16.35 | 0.95 | 0.188 | |
11 | Crabs | 2.5 | 3.79 | 12.50 | 0.95 | 0.303 | |
12 | Squids | 3.2 | 1.475 | 3.10 | 8.00 | 0.95 | 0.388 |
13 | Melon seed | 3.0 | 0.101 | 2.41 | 24.00 | 0.97 | 0.100 |
14 | Pomfret | 3.4 | 0.393 | 3.03 | 15.15 | 0.93 | 0.200 |
15 | Upeneus bensasi | 3.1 | 2.10 | 10.28 | 0.95 | 0.204 | |
16 | Chub mackerel | 2.8 | 0.045 | 2.62 | 8.80 | 0.97 | 0.298 |
17 | Silver croaker | 3.4 | 0.034 | 3.55 | 7.71 | 0.96 | 0.460 |
18 | Lionhead croaker | 3.3 | 0.060 | 7.36 | 29.16 | 0.96 | 0.252 |
19 | Greater lizardfish | 3.3 | 0.020 | 4.26 | 7.12 | 0.93 | 0.598 |
20 | Japanese jack mackerel | 3.5 | 0.412 | 2.15 | 7.86 | 0.90 | 0.274 |
21 | Threadfin bream | 3.1 | 0.486 | 2.07 | 7.25 | 0.93 | 0.286 |
22 | Bigeyes | 3.4 | 0.216 | 2.94 | 8.00 | 0.92 | 0.368 |
23 | Japanese scad | 3.1 | 0.461 | 1.87 | 11.08 | 0.92 | 0.169 |
24 | Cutlass fishes | 3.8 | 1.200 | 3.02 | 6.21 | 0.91 | 0.487 |
25 | Small pelagic fish (30 cm−) | 2.8 | 1.772 | 4.26 | 17.04 | 0.97 | 0.250 |
26 | Large pelagic fish (30 cm+) | 3.1 | 0.368 | 4.26 | 6.27 | 0.96 | 0.679 |
27 | Benthopelagic fish | 2.8 | 0.922 | 3.08 | 15.42 | 0.91 | 0.200 |
28 | Small demersalfish (30 cm−) | 2.6 | 4.70 | 23.50 | 0.95 | 0.200 | |
29 | Large demersalfish (30 cm+) | 3.0 | 0.164 | 3.50 | 6.21 | 0.94 | 0.564 |
30 | Sharks | 3.8 | 0.005 | 0.20 | 4.13 | 0.10 | 0.048 |
31 | Seabirds | 3.4 | 0.003 | 0.06 | 66.10 | 0.06 | 0.001 |
32 | Turtles | 2.9 | 0.0002 | 0.10 | 2.50 | 0.10 | 0.040 |
33 | Marine Mammals | 4.0 | 0.009 | 0.04 | 14.77 | 0.05 | 0.003 |
34 | Detritus | 1.0 | 200.000 | - | 0.00 | 0.16 |
B―biomass, P/B―production to biomass ratio, Q/B―consumption to biomass ratio, P/Q―production to consumption ratio, EE―ecotrophic efficiency.
nomic structure of a region. It is also a useful tool to assess the socio-economic linkages of a production sector. A SAM can be represented as a square matrix T whose tij element shows the transaction value where the income obtained by account i originates from the expenditure by account j. The matrix of direct coefficient in the PRE SAM model, denoted S, is derived as follows
where S is the matrix of SAM direct coefficients; A is the matrix of technical coefficients, includes sales and purchases; V is the matrix of value added coefficients that includes payments from production accounts to factors; Y is the matrix of value added distribution coefficients that includes factor payments to the institution accounts; C is the matrix of the expenditure coefficients that includes household purchases of industry output; and H is the matrix of institutional and household distribution coefficients that includes inter-household/institution transfer payments.
The SAM model can then be written as follows
or
where x is the vector of total production output; v is the vector of total value added; y is the vector of total institutional income; ex is vector of exogenous goods and services demand (from exogenous stimulus measures, government expenditure/investment, export demand, or other exogenous resources of demand); and ey is vector of exogenous household transfer payment (primarily government transfer payments). Here (I − S)−1 is called the SAM multiplier matrix or matrix of SAM inverse coefficient.
In this paper, the inter-industry accounts of SAM in the PRE are retrieved from the 2002 Guangdong province input-output model (
A simplified basic fish production table that considers the addition of fisheries harvesting sectors to detail the production of fish is presented (
The economy consists of the PRE fishery sectors, including marine capture and fish processing, and the PRD households, and is linked to the rest of the world through the commodity and factor (labor and capital) markets. The economic model combines macroeconomic structure with microeconomic fishery production, thereby reflecting the production chain of the fisheries.
The economic value of an estuary ecosystem is defined on the basis of its relevant ecological features, and its