Coral trout, Plectropomus Ieopardus, is a high-volume, high-priced species in the international live reef food fish trade. Each year more than 8,000 tonnes of fish, worth over a billion Hong Kong dollars, are exported from the Philippines, Indonesia, Malaysia and Australia for consumption in Hong Kong and Mainland China. Its wild populations are believed to be declining in all major source countries with the exception of Australia which manages its fisheries. Concerns over the sustainability of coral trout fisheries, which are major livelihood for some coastal communities, have been raised. To assess whether the fisheries are biologically sustainable, this study developed two different stock assessments synthesizing the best available scientific knowledge and fisheries data of coral trout or grouper stocks for two major sources of production. For the coral trout fishery in the Municipality of Taytay in the Province of Palawan, Philippines, only stock life-history was available in literature, while for Indonesia only catch and effort data were provided for 11 major fishing grounds for groupers including coral trout, by a major live fish trader. Given the nature of the data available, two types of fisheries models were developed for the assessments.
For Taytay, a per-recruit model was constructed to simulate catch and stock response to a range of fishing levels based on life-history processes. With the current fishing level estimated from sampled catch, the model indicated that the fishery was unsustainable in Taytay because the spawning stock was overexploited. Right-based catch control, export quota, minimum size, spawning season and aggregation closures were proposed for the recovery of spawning and the spawning stock. Studying stock abundance, sex change and uses of the fish other than export, for example domestic use and mortality levels, will improve the assessment rigour.
For Indonesia, a mult-grouper species per-area-based Fox model was fitted to recent catch and effort data. The assessment determined catch and trade quotas for management and highlighted the need for rights-based adaptive management. The assessment found on fishing ground where the groupers including coral trout were fished much beyond sustainable levels and suggested immediate reduction of catch and number of fishers. Monitoring catch, effort and stock abundance and understanding larval dispersal and recruitment can help verify model assumptions and improve their accuracy.
For the great many data-poor, unassessed grouper fisheries, similar assessments can be carried out gather data and evaluate fisheries sustainability, while management measures derived from the two assessments here could be used to inform management until more data and assessments become available. Data gaps for improvement of models were identified in the study.
Both assessments in this study viewed community-based management as essential to resolve the weak enforcement capacity of Southeast Asian states in fisheries management. For management in and by communities lacking expertise and resource, a greater synergy between various parties is critical, which includes institutional legitimacy of community’s property rights, outreach and capacity building by NGOs, compliance of traders with regulations, sustainable trade practices as well as financial support from consumer’s choices and philanthropy. / published_or_final_version / Biological Sciences / Master / Master of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/206688 |
| Date | January 2014 |
| Creators | Yin, Xueying, 尹雪莹 |
| Contributors | Sadovy, YJ |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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