||Precious corals have been commercially exploited for their cultural characters and high values for many centuries all over the world. Precious coral fisheries are generally characterized by the ‘boom-and-bust’ trend. The precious coral fishery in Taiwan dates back 1930s, while the pertaining studies on biology and ecology for the resource are still scarce. To understand explicitly the population ecology and function of precious corals in marine ecosystems are critical essentials for substantial management of fishery, and also for improvements of conservation of precious corals. The management of precious coral fishery in Taiwan has been promulgated since January 2009, which also conducting research programs to evaluate the status of precious corals around Taiwan. According to the regulation, the objectives of this study are (1) to collect and maintain the catch and effort data of precious coral fishery of Taiwan, and preliminarily analyse the distribution patterns spatiotemporally; (2) to identify the target species and bycatch species, analyse catch composition and morphormetric measurements.?
A. Fisheries data analysis
The total production of precious corals was 3265.5 kg in 2009 and 2252.2 kg in 2010 (by September). The fishing efforts (Vessel-day) and production mainly aggregated in designated fishing ground (DFG) A regions for both years. The monthly variations in fishing efforts were affected by climate condition. The productions by species were dominated by Momo coral (83% ＆ 88%), second by Miss coral. The productions by commercial categories were dominated by fossilized (77% ＆ 79%) while alive accounted for ca 2% ＆ 4%. The alive coral mainly located on DFG-E region and dominated by Momo and Aka corals. The monthly occurrence rates of alive coral were decreasing in the past 2 years. The high proportion of fossilized corals in production shows not only the low efficiency of non-selective gears in the fishery, but also the low occurrence rate of alive corals in the DFGs. The deviation of fishing vessel positions from logbook records and VMS are averaged 0.01 degree in latitude and longitude. The catch records of logbook are always lower than those of landing data. The management of sessile animals should consider not only the sustainability in population structure but also in functions in the ecosystem which will achieve the targets in fisheries management and conservation.?
B. Biological data analysis
In 2010, it was collected that 7 different Coralliidae species, being included Paracorallium japonicum, Corallium konojoi, C. elatius, C. sulcatum, C. regale, C. sp. nov, and P. inutile. In preciously mentioned 7 species, the description of morphology and characteristics for identification of the first two species were completed in 2009, and these of the other 5 species were the result of this year. Taking under water video is a new project of the survey in this year. In Taiwan, it is the first time to video the habitat of Coralliidae species. According to the report from on-board observers and the type of by-catch specimens, the mesophotic coral in the same habitat with Coralliidae species were affected by precious coral fishery most seriously. It is proposed that in order to understand the impact from precious coral fishery to Coralliidae species and to revise the relative conservative measures, the observation and survey of precious coral fishery should be continued.