Comparative growth and survival of diploid and triploid mozambique tilapia (Oreochromis mossambicus) reared in indoor tanks

In the present study, the effect of cold shock on fertilized eggs of Oreochromis mossambicus was during triploid production. Two males (150 ? 224 g) and six gravid females (150 g to 264 g) were collected. The females were injected with ovulin at a dosage rate of 0.5ml kg(-1), the eggs were stripped into a dry bowl, fertilised with milt, divided into two groups (A and B) and incubated. After three minutes, group A was cold shocked at 50C for a period for 5 min, while group B was incubated normally. Tilapia larvae hatchlings were triplicated and stocked at a density of 200 larvae / liter in the aquaria for four weeks. Results showed that triploid fish had a lower hatchability (58%) and survival rate (47%) than diploid fish (of 85 and 70%, respectively), but a higher specific growth rate of 1.097 as compared to diploid at 0.931. While the improved growth rates have great commercial applications. Further research should be conducted to improve the lower hatchability and survivability of triploid tilapia

The Influence of Alien Fish Species on Native Fish Community Structure in Malaysian Waters

Introduction of alien fish species has resulted in major global change, harming native species and communities throughout the world. The main objectives of this review were to examine the species composition, ecology, and distribution of alien fish species in natural water bodies and evaluate the role and contribution of alien fish species through aquaculture to socio-economic development in Malaysia. The rate of introduction and the number of alien fish species introduced into local habitats have greatly increased since the early twentieth century. A statistical analysis of habitat differences among native fish species in Malaysia indicated that differences in fish assemblage structure in various sites was associated with differences in physical habitat. However, the occurrence of alien species has not only changed the structure of native ichthyo-fauna groups but has also caused ecological damage and economic harm to local fishermen. At present, alien fish species inhabit diverse environments including highland and isolated streams, rivers, rice fields, swamps, drainage areas, dams and reservoirs, lakes created from former mining areas, and estuaries in Malaysia. The examination of species composition, distribution and movement of alien fish in natural habitats revealed that these species have seriously spread and are now distributed in diverse aquatic habitats of Malaysia. This in turn provided evidence that there are no restrictions or limitations to the spreading of alien fish species in the natural habitats of Malaysia

Phylogeography and population structure of inferred from Cytochrome b mitochondrial DNA fragment

Aim : Shad fish of genus Tenualosa subfamily Alosinae (shads) family Clupeidae, are commercially and culturally important estuarine fish in many Asian countries, especially in Sarawak. In this study, the phylogenetics of three species from the genus Tenualosa (Tenualosa toli, Tenualosa macrura and Tenualosa ilisha) was determined. Methodolgy:Sequence analysisof 910 base pairsof Cytochromeb gene were conducted on the samples of indigenous T.toli (N=111) and T. macrura (N=24), which were collected from Sarawak including the samplesofnon-nativeT. ilisha(N=4) obtained from Bangladesh. Results : A total of 28 haplotypes were found with T. toli producing 15 haplotypes, where 13 haplotypes were unique haplotypes while 2shared haplotypes among the6populations. Interpretation :Phylogenetic analysis supported the monophyletic status between the three shad species. The highest intraspecific genetic divergences were recorded between imported samples and samples from other localities. There is evidence of overfishing and recently occurred bottleneck events which led to a population size expansion ofT. toli, especiallyinSebuyau, Daro and Mukah

The Status of Tenualosa toli (Valenciennes, 1847) in the Southwest Coast of Sarawak, Malaysias

The tropical shad of genus Tenualosa (family Clupidae) or locally known as Terubok, are important estuarine fishes, both commercially and culturally in many Asian countries including Malaysia. However, Tenualosa species are subject to heavy fishing pressure and have suffered major declines. The decline of Tenualosa toli catch landing since 1980’s had urged the state government of Sarawak to view with serious concern regarding the problem and directed research and development project to be conducted for maintaining and replenish the natural stock of the species in Sarawak. Therefore, this study was designated to examine the current status on the population of Tenualosa toli within Batang Lupar, Batang Lassa and Batang Saribas in the south-west coast of Sarawak which is known as “core Terubok areas”. The informations that generated from this research will be useful for further studies not only on the ecology, distribution of Tenualosa but also on the conservation and sustainable management of this commercial fish

Distinguishing Hybrids of Golden Thailand and Malaysian Strains of Climbing Perch, Anabas testudineus (Bloch, 1792), Using Multivariate Analyses of Morpho-Meristic Traits

The climbing perch, Anabas testudineus (Bloch, 1792), is a commercially important freshwater fish in Southeast Asia. To meet demand, establishing stock development breeding programmes is essential. However, there is a lack of scientific literature on parent-hybrids differences. This study aims to use morphometric characteristics to identify important predictors and determine their heritability to address the knowledge gap. Two strains of A. testudineus and their corresponding hybrid groups, represented by T1–T4 (T1: golden Thai (♀) × golden Thai (♂), T2: golden Thai (♀) × Malaysian (♂), T3: Malaysian (♀) × Malaysian (♂) and T4: Malaysian (♀) × golden Thai (♂)) were used for the experiment. Thirty individuals of each strain were randomly selected from their respective tanks for morphometric characteristics assessment. Twenty-five morphometric measurements were taken, and adjustments were made for body size effects. These measurements were then subjected to multivariate analysis with a 5 % selection intensity for genetic advancement, focusing on body depth and base of anal fin length. The morphometric characters, including postorbital length, lowest body depth,the base of analfin length,total length, standard length, pre-pectoral fin length,the base of pectoralfin length, and base of pelvic fin length based on the canonical coefficient, were identified as distinguishing factors between hybrids and the parental population. The study showed that body length heritability was greater than 60 %, indicating a significant additive genetic effect that surpasses the impact of the environmental effect and thus could be used as a potential characteristic for selective breeding to improve the desired trait

Allometry of mangrove horseshoe crab, Carcinoscorpius rotundicauda along Peninsular Malaysia coastal waters

Carcinoscorpious rotundicauda is mangrove horseshoe crab that inhabit in mudflats ecosystem. The values information on morphometric variability of C. rotundicauda is still limited especially along coastal of Peninsular Malaysia. In this study, the allometric relationship will be applied to make comparison on morphometric parameters of male and female of C. rotundicauda with different ages and population. A total of 158 samples of C. rotundicauda were collected randomly from Merlimau, Melaka and Pantai Balok, Pahang characterized by different environmental conditions in order to study the intraspecific variations using allometry relationship. Body weight for male C. rotundicauda was 88.02±21.71 g and female was 103.12±33.04 g in Merlimau while in Pantai Balok, the mean for body weight in male was 123.23±31.52 g and female was 177.05±70.98 g. All morphometric parameter were converted into logarithmic value as allometric growth analysis. A negative allometric growth (b<3) was recorded for relationship of length/weight- total length analysis in both population. Overall performance showed that increment of all body parts of female C. rotundicauda showed better growth than males. Follow up study on the relationship of horseshoe crab population growth are needed in developing strategies on monitoring, conservation and breeding of horseshoe crab