碩士 / 國立東華大學 / 海洋生物多樣性及演化研究所 / 97 / Pomacanthidae are common coral reef fishes widely distribute in reef coasts of the world. They are of commercial values being captured as marine ornamental fishes due to the varied and attractive colorations. Most of the past studies were related to the reproduction and behavior of the fish, limited knowledge was obtained for their life history. An understanding of biology and ecology of the fish would be beneficial to the assessment of wild population and could be the baseline contribution towards the establishment of artificial propagation technique of the fish. The semicircle angelfish Pomacanthus semicirculatus captured by local fisheries were collected monthly in the fishing harbors of Nanfanau in Ilan (IL), Chengkung in Taitung (TT) and Hengchun Peninsula in Pingtung (PT) between November 2007 and December 2008. Life history traits of reproduction, early life history, age and growth were elucidated by examinations of gonad and otolith. Body colorations of a sum of 646 semicircle angelfish could be categorized into four stages, namely the juvenile coloration (length range of 23~97 mm), pre-transition (131~220 mm), post-transition (165~292 mm) and adult coloration stages (210~464 mm). Length-weight relationships were different among areas, which the b coefficient 3.05 in TT was significantly smaller than those of 3.12 (IL) and 3.16 (PT). A combination of gonadosomatic index and histological examination of gonads suggested that the lengths at sexual maturity (Lm) were ca. 337 mm (IL) and 406 mm (TT). Spawning seasons of the fish differed among areas, which the reproductive activities in winter season were found for TT and PT but not for IL individuals. Microstructural examinations of daily growth increment count, mark formation and increment feature variations on the sagittal plane of polished otoliths indicated that an otolith mark with occurrence of accessory primordia could be observed at ca. 6th day post-hatching (dph), which was suspected to correspond with the transition of nutrients supply in early life stage of fish. Another otolith mark with significant decrease of increment width and the change in increment transparency were revealed at 13th dph, which was recognized as the timing of larval settlement. Regularly formed growth rings could be discerned on the transverse plane of polished otolith. Marginal increment analysis evidenced that the growth rings were deposited annually between December and January. Maximum ages of the fish were determined to be 21~23 yrs for the three areas. Parameters of the von Bertalanffy growth formula (VBGF) by length were 437.1 mm for asymptotic length (L∞) and 0.16 yr-1 for growth coefficient (k) in IL, 476.05 mm and 0.12 yr-1 (TT), 401.67 mm and 0.16 yr-1 (PT), which the larger L∞ and lower k were found in TT than other areas. A correspondence among inflection points of the weight VBGF, coloration stages and Lm indicated that the maximum instantaneous rate of growth in weight (IP1) was referred to the pre-transition stage, whereas the maximum growth rate in body weight (IP) was to the adult coloration stage. The Lm occurred after the IP and the later maturation was found for TT than those of IL. In general, life history traits of TT individuals were different from others, which were speculated to be attributed to the different fishing pressures encountered among areas. However in comparison with other fishes, the semicircle angelfish was of slow growth and late reproductive investment.
| Identifer | oai:union.ndltd.org:TW/097NDHU5270021 |
| Date | January 2009 |
| Creators | Lu-Peng Wang, 王律棚 |
| Contributors | Chih-Wei Chang, 張至維 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 72 |
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