Reduction and management of commercial fishing effort in the Gulf of Thailand by using bio-economic modeling | |
| Author | Pavarot Norannarttragoon |
| Call Number | AIT Diss. no.AQ-13-03 |
| Subject(s) | Fisheries--Management--Thailand Fisheries--Thailand--Fishing effort |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Aquaculture and Aquatic Resources Management |
| Publisher | Asian Institute of Technology |
| Abstract | Since the introduction of modern fishing technology in the 1960’s, fish production in the Gulf of Thailand has steadily increased. Th e marine fisheries biologists have long recognized that increased fish production does not necessarily imply the sustainable use of fisheries resources. Excessive fishing effort is a serious threat to fisheries resources. To achieve sustainable fisheries, enhance marine fish supply and improve fishers’ livelihood, the suitable fisheries management measures taking both the sustainability of fisheries resources and economic consequences into account are needed to be done as soon as possible. Study on reduction and management of commercial fishing effort in the Gulf of Thailand was based on 2007’s fisheries resources and economic status. Fisheries biological data were collected monthly from six fishing fleets, including small-sized Thai purse seine (TPS1), large-sized Thai purse seine (TPS2), purse seine with fish aggregating devices (FAD), small-sized otter board trawl (OBT1), medium-sized otter board trawl (OBT2) and pair trawl (PT) at fishing ports in thirteen provinces along the Gulf of Thailand. CPUE, species composition and length frequency were analyzed. Fishing ground, fishing effort, fishing gear characteristic and cost and return were obtained from interviewing the fishers. The results on the resource status in 2007 show ed that average CPUE of TPS1, TPS2 and FAD was 1,892, 2,317 and 3,351 kg/day respectively, OBT1, OBT2 and PT was 22, 33 and 121 kg/hour respectively. Main species composition of TPS1 and TPS2 was short mackerel 28% and 30% of the total catch respectively, FAD was Indian mackerel, 25%, OBT1 was Penaeid shrimps, 31%, and OBT2 and PT was squids, 13% and 19% respectively. Small-sized economically important species showed a high percentage in trawls’ trash fish. The length measurement of seven economically important species showed that the average length of six species wa s smaller that size at first maturity. Several indications of possible problems have been discussed, i.e., change in the percentage of species composition, decline in trawls’ CPUE , decline in the mean length and the huge number of juvenile fish caught are all si gn that management actions are needed.The analysis of cost and return of purse seine fisheries disclosed that the net return of 0.7, 0.9 and 1.3 million Baht could be obtained from TPS1, TPS2 and FAD. The inflation rate and the aquatic price index were applied to an available report of trawls’ cost and return analysis to explore the financial status. The results showed that commercial fisheries could be operated in long term period. BEAM 5 was used to predict the future bio- economic features of alternative management strategies. Nine species and six commercial fleets were selected to represent the entire fisheries resources in the Gulf of Thailand. A series of simulations were run to assess the impact on the catch and economic performance. The fisheries situation in 2007 showed that the total catch was 802,770 tonnes making up 13,442 million Baht, government finance was in a deficit of 15 million Baht and economic analysis was 8,617 million Baht. To recommend the suitable fisheries management measure taking the sustainability of fisheries resources and economic consequences into account, the simulation results demonstrated that the reduction of fishing effort by 25% would increase the total catch and economic benefit. However, government finance still depicted a negative cash flow. Increase in taxes and fee could be a government beneficiary. The vessel buyback program could be a tool to reduce the effort, although the government finance would be turned to a large deficit. Closure of some area in some period combining with reduction of effort by 25% offered the highest catch and economic cash flow. The Gulf of Thailand’s simulation showed a set of potential fisheries management measures, including reduction of the number of fishing boats although the given reduction rate is tentative. |
| Year | 2013 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Yakupitiyage, Amararatne |
| Examination Committee(s) | Gallardo, Wenresti G.;Shivakoti,Ganesh P.;Mala Supongpan |
| Scholarship Donor(s) | Ministry of Agriculture and Cooperatives |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2013 |