PEMIJAHAN DAN PERKEMBANGAN EMBRIO IKAN PELANGI (Melanotaenia spp.) ASAL SUNGAI SAWIAT, PAPUA

Abstract

Ikan pelangi asal Sungai Sawiat, Papua merupakan ikan hias endemik yang belum diketahui data biologinya. Penelitian ini bertujuan untuk mengetahui jumlah telur yang dihasilkan, fertilitas dan daya tetas telur serta tahapan perkembangan embrio ikan pelangi asal Sungai Sawiat. Induk jantan dan betina ukuran 10–15 cm sebanyak 20 ekor, dipelihara dalam bak beton berukuran 2,5 x 2,5 x 1,0 m3 dengan sistem resirkulasi dan diberi pakan berupa cacing darah (bloodworm) dengan frekuensi 3 kali sehari secara ad libitum. Dua ekor induk betina dan satu ekor induk jantan yang matang gonad dipijahkan dalam bak beton berukuran 1,0 x 1,0 x 0,75 m3 dan diberi tanaman air berupa eceng gondok sebagai pelindung serta media penempelan telur. Pengamatan ada tidaknya telur dilakukan setiap pagi dan sore hari selama 14 hari. Telur yang didapat dicatat baik fertile maupun infertile. Sebanyak 20 butir telur ditetaskan dalam basket plastik berukuran 13 x 10 x 5 cm dan selanjutnya diamati perkembangan embrionya dengan menggunakan mikroskop. Hasil pengamatan menunjukkan bahwa jumlah telur yang dihasilkan sebanyak 436 butir per dua ekor induk betina (218 butir per ekor), fertilitas 77,06%; daya tetas telur 74,71%; dan telur menetas setelah 8.579 menit (142 jam 59 menit) pada suhu air inkubasi 27,6 – 28,3oC.

Rainbow fish species originated from Sawiat River of Papua is one of Indonesian endemic species which its biological data has not been catalogued properly. The objectives of this research were to know the number of eggs (fecundity), fertility and hatchability and also the stages of embryonic development of the fish. Total of 20 male and female broodstock around 10–15 cm in size, reared in concrete tank sized 2.5 x 2.5 x 1.0 m3 equipped with closed recirculating water system and fed with bloodworm  ad libitum 3 times daily. Two already matured females and one male were selected for natural breeding and then transferred to another concrete tank (1.0 x 1.0 x 0.75 m3 in size) and equipped with water hyacinth as shelter and media for egg attachment. The released eggs were observed twice daily, in the morning and in the afternoon, during the 14 days of research. 20 fertilized eggs were incubated in a plastic basket (13 x 10 x 5 cm in size) for preparation of embryonic development observation under binocular microscope. The result showed that the total egg produced by 2 females were 436 with fertility of 77.06%, and hatchability of 74.71%. Incubated eggs hatched after 8,579 minutes (142 hours and 59 minute) at the temperature range of 27.6–28.3oC.