Ikan baung (Hemibagrus nemurus) memiliki prospek bagus untuk dikembangkan sebagai komoditas budidaya di Indonesia karena citarasa daging yang enak banyak diminati konsumen. Dewasa ini, peningkatan produksi benih dapat dilakukan melalui pemijahan buatan dengan manipulasi hormonal. Penelitian yang dilakukan bertujuan untuk mengevaluasi produksi induk ikan baung melalui pemijahan buatan dengan dosis penyuntikan GnRH-a berbeda. Penelitian dilakukan di Instalasi Riset Plasma Nutfah Perikanan Air Tawar, Cijeruk, Bogor pada bulan November 2017. Induk betina ikan baung yang digunakan berukuran 465,0 ± 71,8 g; dan induk jantan 426,3 ± 46,8 g. Induksi dilakukan dengan penyuntikan hormon GnRH-a dengan tiga dosis yang berbeda pada induk betina (0,3; 0,5; dan 0,7 mL/kg bobot badan), dan ikan jantan dengan dosis 0,4 mL/kg bobot badan. Masing-masing perlakuan terdiri atas tiga ekor induk betina sebagai ulangan. Hormon disuntikkan secara intramuskular, diberikan dua kali penyuntikan 35% dari dosis total pada penyuntikan pertama, dan 65% diberikan pada penyuntikan kedua, dengan interval waktu penyuntikan delapan jam. Parameter yang diamati yaitu jumlah telur ovulasi, derajat pembuahan, derajat penetasan, dan sintasan larva selama tujuh hari. Hasil penelitian menunjukkan bahwa dosis penyuntikan hormon GnRH-a 0,5 mL/kg pada induk ikan baung saat proses pemijahan buatan menghasilkan derajat penetasan yang lebih tinggi dibandingkan dosis 0,3 dan 0,7 mL/kg; serta sintasan larva yang lebih baik dibandingkan dosis 0,7 mL/kg. Sedangkan nilai jumlah telur yang berhasil ovulasi dan derajat pembuahan yang relatif lebih baik ditemukan pada perlakuan dosis 0,7 mL/kg dibandingkan dengan dosis 0,3 dan 0,5 mL/kg.Asian redtail catfish (Hemibagrus nemurus) has a good prospect to be developed as aquaculture commodity in Indonesia. It was proved by the demand of consumers regarding to its delicious flesh taste. Recently, efforts to increase seedling production could be implemented through artificial spawning with hormonal manipulation. This study was conducted to evaluate the production of broodstocks through artificial spawning with different doses of GnRH-a. Study was conducted at Research Institute for Freshwater Fisheries Germplasm, Cijeruk, Bogor in November, 2017. The broodstock used in this study was 465.0 ± 71.8 g for females, and 426.3 ± 46.8 g for males. Induction was performed by injection of GnRH-a hormone with three different doses on female broodstocks (0.3, 0.5 and 0.7 mL/kg of body weight), and male broodstocks with a dose of 0.4 mL/kg of body weight. Each treatment consisted of three females as replications. The hormone was injected intramuscularly, given twice injection: 35% of the total dose is given at the first injection, and the remaining 65% was given at the second injection, with an injection time interval of eight hours. The results showed the observed parameters of number of the ovulated eggs, fertilization rate, hatching rate, and larval survival for seven days, treatment dosage of 0.5 mL/kg showed better results (P<0.05) than the dosage of 0.3 mL/kg and 0.7 mL/kg. Parameters observed were number of ovulated eggs, fertility rate, hatching rate, and survival rate for seven days. The results showed that the dosage of 0.5 mL/kg GnRH-a injection to the broodstock during artificial spawning resulted in higher hatching rate compared to 0.3 and 0.7 mL/kg and better larval survival rate than the dosage of 0.7 mL/kg. Meanwhile, the number of ovulated eggs and fertility rate was relatively better in the treatment of 0.7 mL/kg compared with the dosage of 0.3 and 0.5 mL/kg.
Combined Effects of Temperature and Salinity on Hatching and Larval Survival of Commercially Important Tropical Sea urchin, Tripneustes gratilla (Linnaeus, 1758)
