TOLERANSI SALINITAS BENIH PERSILANGAN 3 STRAIN IKAN NILA (Oreochromis niloticus) DENGAN IKAN MUJAIR (O. mossambicus)

Penelitian ini merupakan studi awal yang akan digunakan sebagai bahan untuk penelitian tahap selanjutnya, dalam rangka mendapatkan kandidat ikan nila toleran salinitas. Penelitian ini dilakukan di Loka Riset Pemuliaan dan Teknologi Budidaya Perikanan Air Tawar, Sukamandi pada bulan Maret 2009. Ikan yang digunakan adalah hasil persilangan 4 strain, nila BEST (Bogor Enhancement Strain of Tilapia), nila merah (Red NIFI), NIRWANA (Nila Ras Wanayasa), mujair (O. mossambicus). Persilangan dilakukan secara dua arah penuh (full diallel crossing) sehingga dihasilkan 16 populasi, tetapi yang bertahan hidup ada 14 populasi. Pengujian secara langsung dilakukan pada media bersalinitas 10‰, 20‰, dan 30‰ sebanyak 10 L dengan kepadatan 1 ekor/L, rata-rata bobot 0,22 g dan rata-rata panjang total 2,16 cm. Metode yang digunakan adalah metode eksperimen (LT50) dengan Rancangan Acak Lengkap (RAL) 3 perlakuan dan 3 ulangan. Analisis data menggunakan analisis keragaman (one-way ANOVA) jika berbeda nyata dilanjutkan dengan uji lanjut Tukey. Hasil penelitian menunjukkan bahwa benih persilangan memiliki toleransi lebih tinggi pada salinitas 10‰ berbeda nyata (P<0,05) dibanding dengan salinitas 20‰ dan 30‰. Pada uji papar langsung terhadap salinitas 30‰ terdapat lima persilangan terbaik yaitu, Mujair x NIRWANA (2,49 j), Mujair x Red NIFI (1,91 j), NIRWANA x Red NIFI (1,86 j), NIRWANA x Mujair (1,85 j), dan BEST x Mujair (1,65 j).This research was an initial study that will provide information for the next research in order to get a candidate of salinity tolerance tilapia. This study was conducted at the Research Institute for Freshwater Fish Breeding and Aquaculture, Sukamandi, in March 2009. The fish used in this experiment comprised of hybrids of 4 tilapia strains, i.e. BEST (Bogor Enhancement Strain of Tilapia), Red NIFI, NIRWANA (Nila Ras Wanayasa), and Mozambique tilapia (O. mossambicus). The hybridizations were conducted following full diallel crossing yielding 16 populations, of which, only 12 populations could survive the treatments. Fish with an average of body weight of 0.22 g and total length of 2.16 cm were directly stocked to 10 L media with salinity of 10‰, 20‰, and 30‰ at a density of 1 fish/liter. The method used in this experiment was Lethal Time 50% (LT50) with Complete Random Device (RAL) consisted of 3 treatments and 3 replications. The result was analyzed by the analysis of variance (one-way ANOVA). Further, Tukey test was carried-out if the ANOVA showed a significance difference among treatments. The result showed that the hybrids of tilapia had significantly different (P<0,05) higher tolerance to salinity of 10 ‰ than that of 20‰ and 30‰. The best five populations with direct exposure to salinity 30 ‰ were Mozambique tilapia x NIRWANA (2.49 hours), Mozambique tilapia x Red NIFI (1.91 h), NIRWANA x Red NIFI (1.86 j), NIRWANA x Mozambique tilapia (1.85 h), and Mozambique tilapia x BEST (1.65 h)