Indonesia.- Attempts to produce the comet fish were still done in the traditional way with the low spawning success rates. The spawning failure was thought to be caused by two factors, the first was the failure in preparing the parent that was really mature gonad and ready to spawn (mating), and the second factor was the failure in stimulating the parent to cause the ovulation.
Three researchers from Department of Aquaculture, Faculty of Fisheries and Marine Science (FPIK), Bogor Agricultural University (IPB) namely Kukuh Nirmala, Ahmad Habibie, and Harton Harfah, conducted a research about the influence of the electric field on the development of the gonad of comet fish of Carassius auratus auratus.
“The gonad maturity is a particular stage of the gonadal development before and after spawning. During the process of reproduction, some energy is used for the development of the gonads, and the fish gonads will reach maximum when the fish will spawn, then it will decline rapidly during the spawning process lasting until the completion,” said Nirmala.
The purpose of this research was to evaluate the effect of the time duration of the exposure of the electric field with the voltage of 10 volts to the development of the gonal of comet fish maintained in the 3 ppt salinity medium for 21st day.
The team provided four different treatments in the experiment, namely: control treatment, two minutes, four minutes, and six minutes. The test fish used was the female comet fish with the number of fish used was 4 per aquarium with the total average length of 12.27 cm and the body weigth average of 22.29 g.
From the experimental result, the team found that the treatment of the electric field of 10 volt with the duration of the eletrict field exposure at all treatments in 3 ppt salinity maintenance medium did not give the significant effect to the gonadosomatic index parameter (GSI) and the development of the gonad of comet fish.
“The influence of the time duration of the electric exposure by 10 volts on 3pt pepticity media on the comet fish against the parameter ratio of the length of intestine to the body length, the gonadosomatic index, the hepatosomatic index, the daily growth rate and the survival is no significant difference between all treatments. However, to parameter of the feed consumption amount, there is a real difference between treatments. The two minute treatment shows the result which tends to be higher than the control treatment, four, and six minutes,” he said.
The result of the research showed that the two-minute treatment had the highest GSI score of 7.06 percent on the 21st day compared with the control, while the six-minute treatment showed the lowest score of 5.52 percent on the 21st day. During the process of reproduction, most metabolic outcomes were directed to the development of the gonads. This caused a change in the gonads itself, at the time of the gonadal maturation, the female fish would experience the increase in the body weight due to the increase of ovary weight.
Source: Bogor Agricultural University
