Komar Sumantadinata

Genetic change in the first and second generations of hatchery stock of black seabream

Abstract The genic variability of hatchery stocks of black seabream was examined using 42 loci of biochemical markers, such as ADH, CK, EST, GPD, IDH, MDH, PGD, SDH, SP and others. The genic variability of the hatchery stocks, indicated by the proportion of polymorphic loci, number of alleles per locus, and heterozygosity, was lower than that in the natural population. A divergence in allelic frequency was observed in a few intermediate alleles, as shown by the indicators, Fst and genetic distance. Based on the magnitudes of random genetic drift in marker loci, the numbers of contributing parents in two first generation populations were estimated to be as small as 16 and 26 although the number of parents held in a hatchery tank was 102. It is proposed to increase the number of contributing parents in the program to propagate black seabream in Japan to avoid the influence of inbreeding.

Nitrogen input, primary productivity and fish yield in fertilized freshwater ponds in Indonesia

Abstract Twelve 0.2-ha ponds in West Java were fertilized weekly with four levels of chicken manure (12.5, 25, 50, and 100 g dry weight/m 2 week −1 ) during a 149-day growout experiment for Nile tilapia ( Oreochromis niloticus ) production. Laboratory leaching experiments for measuring dissolved inorganic nitrogen (DIN) release from chicken manure showed that nitrogen was released as ammonia-N, which was rapidly lost from the manure and leveled off at about 6 mg NH 4 N/g dry weight chicken manure after 4–5 days. Allochthonous DIN input from both chicken manure fertilization and almost daily source-water additions ranged from 0.055 to 0.142 g N/m 2 day −1 . Source water contributed more nitrogen than manure in all but the highest fertilization treatment. Pond averages of net primary productivity (NP) ranged from 0.54 to 2.00 g C/m 2 day −1 , while gross fish yield at harvest ranged from 4.9 to 15.7 kg fresh weight/ha day −1 . Net fish yield (NFY) was linearly correlated to both the dry weight sum of NP and chicken manure fertilization ( r 2 =0.97) and allochthonous DIN input ( r 2 =0.96). Results suggest that Nile tilapia obtained organic carbon from both primary productivity and manure-derived detritus. DIN availability limited algal productivity at a chicken manure fertilization rate of 100 g dry weight/m 2 week −1 when microbial decomposition of manure supplied sufficient CO 2 . Incorporation of allochthonous DIN input into NFY increased significantly from 15.0% at the three lower fertilization rates to 25.4% at the highest loading rate. Using organic fertilizers proportionally rich in phosphorus and carbon relative to nitrogen may maintain this elements limitation of algal productivity. Efficient utilization of DIN input also may minimize total and un-ionized ammonia concentrations. In the absence of deleterious ammonia effects on survival and growth, fish yields can be readily predicted from measurements of nitrogen inputs.

Comparison of electrophoretic allele frequencies and genetic variability of common carp stocks from Indonesia and Japan.

Abstract Allele frequencies and genetic variability of six stocks of common carp collected from Indonesia and three stocks from Japan were evaluated. Twenty-three loci were identified from 11 enzyme and protein systems. Five loci were polymorphic for the Indonesian stocks and eight loci were polymorphic for the Japanese stocks. PGM, EST and GPI were useful for comparison between the Indonesian and Japanese stocks as well as stocks from Europe and China. In general, genetic variability of the stocks from Japan was higher than that of stocks from Indonesia. The genetic distance between pairs of stocks, based on 23 isozyme and protein loci, showed distinct genetic differentiation between Japanese and Indonesian stocks. The sources for the Japanese and Indonesian common carp are discussed in relation to the European and Chinese common carp.

Present state of common carp (Cyprinus carpio L.) stocks in Indonesia

Abstract The common carp ( Cyprinus carpio L.) stocks in Indonesia are descendants of common carp brought from China, Europe, Taiwan and Japan. The Punten carp and Majalaya carp are the result of selection conducted in Indonesia. Based on morphological characteristics, there are at least 10 common carp stocks known to date. Some stocks can be easily distinguished by observing their morphological characteristics, e.g. Majalaya, Sinyonya, Domas, Kancra-domas, red (merah), mirror, long-fin (Kum-pay), and koi. The Punten and Taiwan carp stocks are relatively difficult to identify morphologically. In the field, uncontrolled breeding systems for common carp stocks result in mixed stocks. Purification of the stocks has been conducted since 1989. The second generation of gynogenetic diploids of some stocks has been obtained. Experiments of sex-reversal to change genotype females to functional males are being conducted.

PENGARUH PEMBERIAN HORMON ITe METILTESTOSTERON SECARA ORAL PADA INDI.,K IKAN GAPI (Poecilia retidlau Pcters) STRAIN TUXEDO TERHADAP JENIS KELAMIN KETURUNANNYA

Percobaan dilakukan untuk mengetahui pengaruh pemberian hormon lzo-metiltestosteron secara oral pada induk ikan gapi (Poecilia reticulau Peters) strain tuxedo terhadap ienis kelamin keturunannya.

Keragaman Morfologi Dan Fluktuasi Asimetri Ikan Nila (Oreochromis Niloticus) Dari Danau Tempe (Sulawesi Selatan) Dan Beberapa Sentra Produksi Di Jawa Barat

Keragaman genetik (fenotipe dan genotipe) merupakan informasi dasar yang diperlukan untuk pelaksanaan program pemuliaan ikan nila. Informasi keragaman genetik ikan nila di Indonesia masih sedikit diperoleh. Oleh sebab itu, metode truss morphometrics dan fluktuasi asimetri yang digunakan pada penelitian ini bertujuan untuk mengukur keragaman morfologi dan fluktuasi asimetri ikan nila dari Danau Tempe (Sulawesi Selatan) dan beberapa sentra produksi di Jawa Barat.