Siti Khalijah Daud

Biochemical Polymorphism in Yellow Catfish, Mystus nemurus (C&V), from Thailand

Yellow catfish, Mystus nemurus (Cuv. & Val.), is becoming one of the major freshwater species farmed by aquaculturists in Southeast Asia. It was of interest to examine levels of genetic subpopulation differentiation among samples of this species obtained from parts of its range, as well as to compare the genetics of wild and hatchery-bred fish. Horizontal starch gel electrophoresis and histochemical staining techniques were used to examine genetic variation within and among eight wild and one hatchery populations of M. nemurus from northern, northeastern, central and southern Thailand. Four tissues (heart, liver, kidney, and muscle) from individual specimens were used to analyze variations at 23 protein-coding loci. Fifteen of the 23 loci examined (65.22%), namely, ACP*, AAT-1*, EST-1*, EST-2*, GPI*, IDH-1*, IDH-2*, MDH-1*, MDH-2*, MDH-3*, ME*, PGM*, 6PGD*, SOD*, and HB*,were polymorphic at the 0.95 level. Observed heterozygosities ranged from 0.041 to 0.111, with an average of 0.068 ± 0.028. Genetic distances ranged from 0.005 to 0.164. The greatest genetic distance was found between the Chainat and the Suratthani populations (0.164), a level indicative of subspecific differentiation in M. nemurus from within Thailand.

Fingerling production and stock enhancement of Mahisefid (Rutilus frisii kutum) lessons for others in the south of Caspian Sea

Rutilus frisii kutum (Kamensky 1901) is one of the economically important fishes that migrate for spawning to rivers in the Caspian Sea. However, the fish populations have slowly decreased in recent years. The declining of these resources has resulted from some activities by the Iranian Fisheries Organization (IFO is responsible for stock enhancement) to catch some broodstocks of Rutilus frisii kutum from their natural spawning rivers. The broodstocks are caught for artificial propagation of the fish. Artificial propagations are carried out every year to produce fingerlings to be released into the rivers in the Caspian Sea. In recent years, total catch of this fish have greatly fluctuated due to the disruption of the natural spawning grounds and over fishing. The substantial reduction to 1,298 metric tons, the lowest total catch reported in 1984–1985, could be due to over-exploitation of the fishery resources. However, the total catch has increased after the fingerlings release programs started in 1979. The total numbers of Rutilus frisii kutum fingerlings released had increased from 12 million to 225 million in 2002, to 155 million pieces in 2003, to 179 million pieces in 2004, 229 million pieces in 2005, 174 million pieces in 2006, 262 million pieces in 2007 and 187.1 in 2008. The total catch was also increased from 6,417 metric ton to 8,984 metric ton, to 7,036 metric ton, to 9,631 metric ton and 16,117, 17,196, 14,835 in years 2002, 2003, 2004, 2005, 2006, 2007 and 2008, respectively.

Association of annual hormonal profile with gonad maturity of mahseer (Tor tambroides) in captivity.

Annual gonad hormonal profile of wild, matured mahseer (29 males and 23 female) averaging in weight between 0.95±0.26 and 1.19±0.23 kg for males and females, respectively, were investigated from November 2007 to November 2008 using enzyme-linked immunosorbent assay (ELISA) technique. Blood was collected from caudal vein, monthly and plasma separation by centrifugation was done to measure reproductive hormones: 17β-estradiol (E(2)), testosterone (T), and 11-keto-testosterone (11KT). Gonads were sampled for histology processing to observe their maturity. Highest T level in females and males was recorded at 0.22±0.016 and 0.88±0.014 ng/ml, respectively. The 11KT showed several peaks and the highest value was noted at 0.7±0.018 ng/ml in November 2008. The female E(2) initially was at 1.48±0.16 ng/ml and significantly increased (P<0.05) to 1.53±0.39 ng/ml in November 2008. Ovaries were laden with oocytes in several stages in all the samples while testes gonad showed a high level of spermatids throughout the year. Changes in plasma level of the gonadal hormones were correlated with the ovarian and testes maturities. In conclusion, the study suggests that mahseer can be categorized as asynchronized and multiple spawner. The information gathered is important for appropriate breeding and conservation programs of the Malaysian mahseer.

Identification of quantitative trait locus (QTL) linked to dorsal fin length from preliminary linkage map of molly fish, Poecilia sp.

A preliminary linkage map was constructed by applying backcross and testcross strategy using microsatellite (SSR) markers developed for Xiphophorus and Poecilia reticulata in ornamental fish, molly Poecilia sp. The linkage map having 18 SSR loci consisted of four linkage groups that spanned a map size of 516.1cM. Association between genotypes and phenotypes was tested in a random fashion and QTL for dorsal fin length was found to be linked to locus Msb069 on linkage group 2. Coincidentally, locus Msb069 was also reported as putative homologue primer pairs containing SSRs repeat motif which encoded hSMP-1, a sex determining locus. Dorsal fin length particularly in males of Poecilia latipinna is an important feature during courtship display. Therefore, we speculate that both dorsal fin length and putative hSMP-1 gene formed a close proximity to male sexual characteristics.

Mitochondrial Genetic Differentiation of spirlin (Actinopterigii: cyprinidae) in the south caspian sea basin of Iran

Background Knowledge about Alburnoides remains lacking relative to many other species, resulting in a lack of a systematic position and taxonomic diagnosis. Basic biological information for Alburnoides has been constructed, and it is necessary to understand further and obtain more information about this species. Its phylogenetic relationships are still debated and no molecular data have been used to study this taxon in Iran. A holistic approach for genetic methods was adopted to analyze possible spirlin population differences at selected centers in the south Caspian Sea basin of Iran. Methods The phylogenetic relationships were determined based on 774 base pairs of the mitochondrial cytochrome b gene of 32 specimens of spirlin from nine locations in the south Caspian Sea drainage basin of Iran. The nucleotide sequences were subjected to phylogenetic analysis using the neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian methods. Results The mitochondrial gene tree largely supports the existence of three major clades. The western populations (clade I) may be considered as Alburnoides eichwaldii, whereas the Talar river populations (clade II) are represented as Alburnoides sp. 1 and the eastern populations (clade III) may be distinct taxa of Alburnoides sp.2. Conclusion This molecular evidence supports the hypothesis that A. bipunctatus does not exist in the south Caspian Sea basin of Iran, and that the western and eastern populations are distinct taxa.