Selection of broodstock of Tiger Prawn, penaeus monodon fabricius, on the basis of Morphometric traits

Mature Penaeus monodon were collected from Kedah, Perak, Terengganu, johore and Sabah waters in Malaysia. Selected morphometric characters and body weight Were measured individually. The results showed that the females were significantly larger (P<O.05) than the males in all locations. Stepwise regression analysis indicated that carapace length alone is sufficient to explain the variance in body weight for male and female prawns and can thus be used as a criterion for the selection of broadstock. The logarithmic relationships between body weight and total length. body weight and carapace length, and between carapace length and total length for both sexes were also calculated

Length-weight relationships of seven catfish species in Peninsular Malaysia.

The study described the Length-Weight Relationship (LWR) of commercially important and indigenous freshwater catfishes from Peninsular Malaysia. Seven species of freshwater catfishes from three families (Bagriidae, Clariidae and Pangasidae) were collected from various rivers in Peninsular Malaysia. Allometric coefficient, b in LWR varied between 2.19 and 3.20. The LWR with high correlation coefficient (r2) is significant for all species except P. nasutus. The present study also documented first reference for Pangasius nasutus and Pseudomystus siamensis

Cross species amplification of ikan kelah, Tor tambroides by using Mystus nemurus microsatellite markers

Thirty eight microsatellite markers developed from a Random Hybridising Microsatellite (RAMs) enrichment protocol created from the DNA of the river catfish, ikan baung, Mystus nemurus were screened to cross amplify ikan kelah, Tor tambroides . Only five primers which amplified bands at the expected allele size regions were used for characterizing this species. The observed heterozygosity values were higher than the expected heterozygosity values for the bands amplified by primer pairs MnSC4-3B, MnLR2-1-52A and MnRmC3-1 across the three populations but the bands amplified by primer pairs MnSC4-1A and MnLR2-1-17B showed lower observed heterozygosity values than the expected heterozygosity values. The mean FIS value across the three populations was negative, indicating no deficit in heterozygosity. The mean value of FST was low indicating no gene was fixed within populations relative to the total population. The high value of Nm suggested high gene flow among the three populations. Both the (x2) chi-square and the (G2) likelihood ratio tests showed significant differences (P<0.05), indicating deviations from Hardy-Weinberg equilibrium in most loci except for one locus (MnSC4-1A) in the Negeri Sembilan population and two loci (MnLR2-1-52A and MnSC4-1A) in the Kelantan population. The genetic distance values generated ranged from 0.1053 to 0.1960. The UPGMA dendrograms constructed from the genetic distances based on the microsatellite markers showed that the Negeri Sembilan and Kelantan populations shared a similar cluster while the Pahang population was on its own

Growth performance and gonad development in Diploid and Triploid Clarias batrachus (Linnaeus)

Full siblings of diploid and triploid walking catfish, Clarias batrachus, were reared in rectangular fibreglass tanks starting at the age of three weeks. Growth performances of diploids and triploids were compared by feeding with a 30% protein diet. At the end of the study period growth rate was found to be insignificantly different (P>0.05) between the diploid and the triploid. However, triploid fish had poorly developed gonads. Triploid ovaries contained fewer primary oocytes with some abnormal maturing oocytes. Triploid testes contained fewer seminiferous tubules and a larger amount of connective tissue

Intraspecific polymorphism in mystus nemurus (C&V) detected by RAPD-PCR fingerprinting

Yellow catfish, Mystus nemurus (C&V), is becoming one of the majorfreshwater species farmed l7y aquaculturists in Southeast Asia. It was of interest to examine levels of genetic sub-population 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. The genetic aspects of variation in the fish, which were collected from eight wild populations throughout Thailand and a hatchery stock, were determined at molecular (DNA) level using the technique ofRAPD-PCRfingerprinting. Five arbitrary primers namely OPA-11, OPA-14, OPA-18, OPA-19 and OPA-20 were chosen to amplify products, which showed 28 polymorphic loci in 9 populations. The highest genetic distance (D) was found between Chainat and Suratthani populations with the value of 0.289, while the lowest was found in Songkhla population and hatchery stock with the value of 0.087. The dendrogram depicts the genetic relationship among populations of M. nemurus, which are grouped into four clusters according to their regional areas

Morphometric analysis of Malaysian Oxudercine goby, Boleophthalmus boddarti (Pallas, 1770)

The Oxudercine gobies or mudskippers are locally known as belacak or "tembakul". These euryhaline fish are amongst the air breathing gobies found in Malaysia. Boleophthalmus boddarti is one of the common mudskippers inhabiting tidal flats, mangrove swamps, estuarines and coastal areas. Conventional and truss morphometrics as well as meristic data from 85 samples in five populations (Pulau Pinang, Kuala Selangor, Banting, Port Dickson and Melaka) of B. boddartiwere analyzed using one-way ANOVA and Principal Component Analysis (PCA). Fifteen morphometric, 28 truss morphometric and 9 meristic data were analyzed to examine the degree of similarity among the five populations. All morphometric characters within and between the populations were significantly different (P< 0.05). Using the conventional morphometric data analysed by PCA, the populations of B. boddarti are clustered into 3 groups, where Banting andMelaka populations form the first group, Pulau Pinang and Kuala Selangor populations the second group and Port Dickson population the third group. In contrast, 3 groups were also clustered based on the truss morphometric data but the grouping was different. The three groups from the truss morphometric data consist of Kuala Selangor and Banting populations in the first group, Melaka and Port Dickson populations the second group and the Pulau Pinang populationthe third group which is distantly separated from the other two groups. The results indicate that the shape of mudskippers in the northern part is distinct from the middle and southern parts of Peninsular Malaysia. Based on meristic data, all populations were centric and no grouping was identified. The length-weight relationship for B. boddarti in this study was described as log W=log 0.754 + 1.029 log TL

Mitochondrial DNA diversity of Tar douronensis valenciennes(Cyprinidae in Malaysian Borneo.

This study examines the population structure and taxonomy of Tor douronensis, an important indigenous freshwater fish species in Malaysian Borneo, by using sequence analysis of 466 base pairs of the mitochondrial cytochrome c oxidase I (COl) gene. A total of 62 fish samples were collected from five locations in Sarawak (N=54) and Sabah (N=8). The phylogenetic analysis using the Neighbour Joining (N]) method supported the monophyletic status between T. douronensis and Tor tambroides, which further reinforced their taxonomic status as distinct species. The T. douronensis haplo types were further divided into three major groups, with the Pelianuh from Sabah forming its own group (Cluster Ill) with strong bootstrap support. The large genetic differences separating the Sabah haplotypes from its Sarawak congeners suggested that the Pelian fish might represent a cryptic species. The current study showed high levels of intra and inter-population variations in T. douronensis. Within all population variations, T. douronensis populations were found, except in Bario. The presence offixed haplotype differences along with high FST values among the populations of T. douronensis, support the conclusion that little or no migration occurred among the extant populations separated by large geographic distances or river systems. However, the sharing of haplotypes between some such populations, for example between Batang Ai and Bario (HS6), and between Batang Ai and Ulu Limbang/Ba Kelalan (HS2) provided support that T. douronensis had a historically widespread natural distribution in the region probably during the Quaternary period. Overall, the present study was able to shed light on the taxonomy and population structure of T. douronensis in Malaysian Borneo

Genetic characterization of the two colour-type of Kelah

Randomly Amplified Polymorphic DNA (RAPD) marker was used to examine the genetic relationships among three populations of two different colour-types (silver-bronze and reddish) of ikan kelah (Tor tambroides). Sixty three individuals of the kelah were sampled from Sia River of Pahang and Kampung Esok River of Negeri Sembilan (silverbronze)and Nenggiri River of Kelantan (reddish). Twelve RAPD primers generated a total of 226 scorable loci with 100% polymorphism across the sixty-three individuals. The RAPD banding patterns and sizes ranged from 4 to 17 and from 100bp to 1500bp, respectively. The intra-population UPGMA dendrogram produced two major clusters, with the Nenggiri River (Kelantan) samples formed a subcluster in both major clusters dominated by the Pahang samples (Cluster 1) and N. Sembilan (Cluster 2) samples, respectively. The inter-population UPGMA showed that the Kelantan samples were genetically closer to the N. Sembilan samples than to the Pahang samples. Thus, the results of this study did not support the hypothesis that the two colour-types of T. tambroides were genetically distinct from each other

Genetic diversity of wild and cultured populations of Penaeus monodon using microsatellite markers

Information on the genetic diversity of Penaeus monodon throughout its natural range in Malaysia is still Hmited even though it is a highly exploited species, thus this study was undertaken to genetically characterize the prawn populations. The P. monodon samples were randomly collected from Malaysian waters and were characterized using thirty polymorphic primer pairs which showed high level of polymorphism. The total number of alleles per locus ranged from 3 to 36 with allele size ranging from 100 to 275 base pairs. The mean observed heterozygosity (0.5166) was less than the expected (0.5552), highly significant deficiencies in heterozygotes were detected in total inbreeding (F IS = 0.5500) and pair-wise genetic differentiation (F ST = 0.6308) among the populations. Both the (χ 2) chi-square and (G 2) likelihood ratio tests detected significant differences (p<0.05) which showed a deviation from the Hardy-Weinberg equilibrium, indicating a probable inbreeding might have occurred in the populations. A Cluster analysis based on genetic distance revealed a fair genetic relationship among all the populations and the pattern was in accordance to the populations' geographical origins. The highest genetic distance (0.7588) was observed between Law as and Bulau Sayak populations while the lowest genetic distance (0.1191) was recorded between the Endau Rompin and Sedili populations. Various levels of genetic diversity of the P. monodon reported in this study indicated their genetic status in Malaysian waters and suitability for breeding and culture purposes. This information provides a basis for improvement through selective breeding and in the design of suitable management guidelines for this genetic material