The aim of this project is to develop and improve the grouper hybridization technology, and to breed a new grouper species with fastgrowing or cold-tolerant character. The gaint grouper Epinephelus lanceolatus were selected as a male parent and the kelp grouper E. moara , the potato grouper E. tukula and orange-spotted grouper E. coioides were selected as a female parent for hybridization.
First, the crossbreeding of groupers were studied. The effects of different sex hormone induced ovarian development of E . moara were evaluated. The results showed that the ovarian maturation was successfully induced by HCG (1000 IU/kg). The embryonic development of hybrid grouper E. moara×E. lanceolatus lasted 30 hours and 24 minutes at 26.5-27.0 °C. The average fertilization and hatching rate were 5.43 ± 3.57 % and 13.87 ± 9.10 % (n = 4), respectivily. The larvae hatched out of the chorion head first. Newly hatched larvae were slightly curved around the yolk sac. The oil globule, in the majority of specimens, was located in the ventroposterior area of the yolk sac. The larvae were reared to two days post hatching. The effects of different sex hormone induced ovarian development of E. coioides were evaluated. The results showed that the ovarian maturation was successfully induced by HCG (1000 IU/kg). The embryonic development of hybrid grouper E. coioides×E. lanceolatus lasted 16 hours and 18 minutes at 30.0-31.0 °C. The average fertilization and hatching rate were 38.77 ± 8.92 % and 36.40 ± 21.22 % (n = 4), respectivily. The larvae hatched out of the chorion head first. Newly hatched larvae were slightly curved around the yolk sac. The oil globule, in the majority of specimens, was located in the ventroposterior area of the yolk sac. The larvae were reared to four days post hatching.
Secondly, the grouper's growth performance and the effects of lowtemperature tolerance were analyzed. After 10 weeks feeding treatment, the final body weight of the juvenile E. coioides, E. lanceolatus and E. fuscoguttatus x E. lanceolatus were 19.15 ± 0.89 g, 33.95 ± 2.69 g and 37.34 ± 1.91 g, respectively; the specific growth rate (SGR) were 2.96 ± 0.18 %/d, 4.28 ± 0.20 %/d and 4.62 ± 0.13 %/d, respectively; the daily weight gain (DWG) were 0.12 ± 0.01 g/d, 0.32 ± 0.03 g/d and 0.37 ± 1.91 g/d, respectively and the percentage weight gain (PWG) were 87.52 ± 9.73%, 210.84 ± 25.72 % and 255.72 ± 25.78 %, , respectively. Above-mentioned parameters of E. lanceolatus and E. fuscoguttatus x E. lanceolatus were significant different higher than that in E. coioides (p < 0.05). This year, the article entitled "Effects of Low-Temperature Stress on Plasma Biochemical Parameters of Longtooth Grouper Epinephelus bruneus, Giant Grouper E. lanceolatus and Hybrid Grouper E. bruneus ×E. lanceolatus" were accepted and published in Journal of Taiwan Fisheries Research. According to that article, we had been established six type plasma biochemical parameters. Moreover, three type low-temperature stress behaviour parameters of E. coioides, E. lanceolatus and E. fuscoguttatus x E. lanceolatus were observed.
Finally, sixty-one yellow grouper E. awoara were collected for broodstock cultivation and domestication. The average body weight and total length were 366.42 ± 27.52 g and 29.10 ± 0.65 cm, respectively. The stocking mortality rate was 35.2 %. During the stocking periods, the causes of death was Benedenia sp. infection (84.0 %) and aggressive behaviour (16.0 %). The 21 dead individuals were dissected. An average ovarian weight was 0.98 ± 0.12 g and GSI was 0.27 ± 0.03. No mature male fish were found.
The long-term goal of this project is to increase the diversity of grouper species, developing hybrid groupers which with economic traits and eventually extended to the aquaculture industry in Taiwan.