Field Report F–19
FISHCODE/MANAGEMENT - GCP/INT/648/NOR
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED
Table of Contents
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A bio-economic modelling workshop was organized in order to improve the information base for the preparation of a fisheries management plan of the small pelagic fisheries of the West Coast of Peninsular Malaysia. Plan preparation by the Department of Fisheries is supported by the FAO/Norway FishCode Project (see Field Reports F-13 and F-17).
Two different modelling approaches have been applied to these fisheries. The surplus production bioeconomic model of the Gordon-Schaefer type suggests that effort at MSY is about 387,000 standard purse seine days producing a MSY of about 109,000 tonnes of small pelagics. At the MSY effort level, however, resource rent is completed dissipated and the fishery incurs an estimated loss of MR 25.6 million. As current effort level (data of 1997) is about 380,000 standardized fishing days, the analysis suggests that fishing effort and capacity are excessive. A resource rent of about MR 77 million might be attainable through the reduction of fishing effort to 180,000 standardized fishing days, i.e. less than half of the current level. This result should be interpreted as providing an order of magnitude only because of the application of a single species model to an assemblage of small pelagic species. One species group, namely Rastrelliger, contributes 73 percent to the ex-vessel value of these fisheries. This result should also be interpreted cautiously because the shoaling nature of small pelagic species was not explicitly taken into account in the modelling exercise.
The second modelling approach was of a much more ambitious nature because it attempted to model the entire catch of the three main gear types exploiting small pelagics -- namely: purse-seiners, trawlers and driftnetters. The total catch modelled in the base year (1997) amounted to just above one half million tonnes with an estimated ex-vessel value of MR 1727.5 million. The small pelagic catch contributed only about one sixth to the total value.
The newly developed BEAM 5 model was used in the workshop. Its biological component is based on the Thompson and Bell approach while the economic component applies the concepts of economic project analysis. Difficulties were encountered in tuning the model with current estimates of growth and natural mortality for several species. Lower estimates were applied that are not supported by past assessment studies. The results are therefore of a very tentative nature. Not affected by whether low or high values of these parameters are correct is the finding that the fisheries produce a significant net economic cash flow (i.e. resource rent) in the order of MR 500 million. The fact that sizeable resource rents are produced in these fisheries can likely be attributed to the positive impact of the comprehensive limited licensing policy adopted by the country as far back as in the early 1980s.
Determination of the scope for increasing economic benefits from West Peninsular Malaysia’s marine fisheries through a reduction of fishing effort, especially of trawling in the inshore zones, is heavily conditioned by the grwoth and natural mortality rates that are assumed, whether high or low. Increased research efforts are recommended in the estimation of critical and sensitive growth and mortality estimates for a range of commercially important species.
GCP/INT/648/NOR Field Report F–19(En)
LIST OF ABBREVIATIONS
2 OBJECTIVES AND PROCEEDINGS OF THE WORKSHOP
3 INTRODUCTION TO BIO-ECONOMIC MODELLING
3.1 Introduction of the Gordon-Schaefer model
3.2 Presentation of Past Studies
3.3 The BEAM 5 model
4 MODEL IMPLEMENTATION AND MODELLING RESULTS
4.1 Gordon-Schaefer and Gordon-Fox models
4.1.1 Background and rationale
4.1.2 Model limitations
4.1.3 Model description
4.1.4 Catch and effort data
4.1.5 Biological analysis
4.1.6 Economic analysis
4.1.7 Economic data
4.2 Beam 5
4.2.2 Biological and technical data
4.2.3 Basic model structure and dimensions
4.2.4 Growth, maturity and natural mortality
4.2.5 Gear and discard selection ogives
4.2.6 Number of vessels, effort and capacity
4.2.7 Fishing mortality
4.2.8 Stock numbers, migration and stock biomass
4.2.9 Catches (observed landings)
4.2.10 Tuning of BEAM 5
4.3 Discussion Of Biological Parameter Values
4.4 Beam 5 - Economic Input Data
4.4.2 Harvesting costs
4.4.3 Investment costs of new vessel
4.4.4 Fisheries management costs
4.4.5 Adjustments to arrive at economic costs
4.4.6 Discount rates
4.5 Results Of The Beam 5 Model Simulations
4.5.1 Base year simulation
4.5.2 Reduced effort and capacity simulations
APPENDIX A: LIST OF PARTICIPANTS
APPENDIX B: AGENDUM
APPENDIX C: ABBREVIATED DESCRIPTION OF BEAM 5
APPENDIX D: STANDARDIZATION OF FISHING EFFORT
GCP/INT/648/NOR Field Report F–13(En)
GCP/INT/648/NOR Field Report F–17(En)