| Summary: | 碩士 === 國立東華大學 === 海洋生物研究所 === 103 === Captive breeding and rearing coral reef fish (or marine ornamental fish) certainly considered an effective tool to relieve the fishing pressure and ecosystems decay on coral reefs. Coral reef fish have diverse habitat niches and display variable and complex spawning patterns. One of the major challenges captive breeding faces is the need to accommodate these spawning patterns in order to produce a diverse range of ornamental fish species that satisfy market and ecological sustainable demands. The aim of this
study was to investigate the natural spawning, early development and larviculture of Istigobius ornatus (demersal spawner) and Cirrhitichthys falco (pelagic spawner), and to provide useful information for coral reef fishes with different spawning patterns captive breeding.
Firstly, the natural spawning, early development and larviculture of the ornate goby (I. ornatus) were studied in captivity. I. ornatus spawned 46 times from 31 October 2013 to 31 October 2014. Each female laid an average 7992 ± 3641 (mean ± SD) eggs during the spawning period. Fertilized eggs were adhesive demersal, oval-shaped and measured 1.31-1.540.46-0.5 mm in diameter. Embryonic development lasted 84 h at 27.0℃-28.0℃. Newly hatched larvae were 2.12 ± 0.15 mm in total length (TL). Transformation of larvae to the juvenile stage and settlement was completed at 30 days post hatching (DPH) and 40 DPH, respectively. The effects of newly hatched larvae at different temperature and salinity on survival rate and survival activity index (SAI) were assessed, respectively. The results showed that temperature 28.0℃, salinity from 10.0 to 30.0 and density of rotifers 20 ind./mL may be a suitable condition for larviculture.
Secondly, the natural spawning, early development and larviculture of the dwarf hawkfish (C. falco) were studied in captivity. C. falco spawned 357 times from 31 July 2014 to 31 July 2015. Each female laid an average 1348 ± 712 eggs during the
spawning period. Fertilized eggs with a mean diameter of 0.76 ± 0.01 mm, were spherical, transparent and buoyant. Embryonic development lasted 20 h 50 min at 27.0-28.0℃. Newly hatched larvae were 1.99 ± 0.09 mm TL and had an oil globule in the posterior area of the yolk sac. The effects of different temperature and salinity on hatching rate, abnormality, survival rate and SAI were compared. The results showed that the
temperature 26.0℃ and salinity ranging from 27.0 to 30.0 may be a suitable water condition for larviculture. The survival was not significantly in feeding treatment B (Euplotes sp. 20 ind./mL), C (Euplotes sp. 10 ind./mL + Brachionus ibericus 10 ind./mL) and D (Euplotes sp. 10 ind./mL + B. ibericus 5 ind./mL + copepods nauplii 5 ind./mL), but all higher than treatment A (starved control) in 3-4 DPH of C. falco larvae.
Finally, the spawning, early life history and captive breeding techniques of two coral reef fish with different spawning patterns were compared. Demersal spawner need an appropriate hard substrate for egg laying. Pelagic spawner should maintain in the
depth tank that can be obtaining sufficient high quality eggs. Both demersal and pelagic spawner larvae rearing were to consider the different times of yolk sac exhaust and first feeding. The long-term goals of this research are to develop aquaculture techniques for raising coral reef fish in captivity to increase our understanding of their ecological requirements, to preserve rare and endangered species, and to reduce harvesting pressure on natural populations.
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