Length-weight relationship and condition factor of fish populations in Temengor Reservoir: indication of environmental health

Length-weight relationship (LWR) and condition factor of seven fish species from the Temengor Reservoir, Peninsular Malaysia were analyzed. A total of 1155 individuals belonging to two families namely Nandidae and Cyprinidae were measured and weighed. The most highly represented family was Cyprinidae which comprised six species. Among these seven species, three species generally showed positive allometric growth, two species showed isometric growth and the other two species showed negative allometric growth. The exponent b value of LWR ranged between 2.601 (Oxygaster anomalura) and 3.157 (Cyclocheilichthys apogon) with a mean of 2.983. The lowest mean condition factor, K was recorded in O. anomalura (0.648 ± 0.131) while the highest value was observed in Pristolepis fasciata (2.194 ± 0.153). This study has contributed to the knowledge of fish populations in this economically important area that could assist fishery management scientists in carrying out future ecological studies in line with the strategies of conservation, restoration and management

Genetic structure of the snakehead murrel, Channa striata (channidae) based on the cytochrome c oxidase subunit I gene: Influence of historical and geomorphological factors

Nucleotide sequences of a partial cytochrome c oxidase subunit I gene were used to assess the manner in which historical processes and geomorphological effects may have influenced genetic structuring and phylogeographic patterns in Channa striata. Assaying was based on individuals from twelve populations in four river systems, which were separated into two regions, the eastern and western, of the biodiversely rich state of Perak in central Peninsular Malaysia. In 238 specimens, a total of 368-bp sequences with ten polymorphic sites and eleven unique haplotypes were detected. Data on all the twelve populations revealed incomplete divergence due to past historical coalescence and the short period of separation. Nevertheless, SAMOVA and FST revealed geographical structuring existed to a certain extent in both regions. For the eastern region, the data also showed that the upstream populations were genetically significantly different compared to the mid- and downstream ones. It is inferred that physical barriers and historical processes played a dominant role in structuring the genetic dispersal of the species. A further inference is that the Grik, Tanjung Rambutan and Sungkai are potential candidates for conservation and aquaculture programmes since they contained most of the total diversity in this area

EFFECTIVENESS OF THE FERMENTATIVE EXTRACT OF Lactobacillus acidophilus AS ANTIMICROBIALS AGAINST Aeromonas hydrophila

The purpose of this study was to evaluate the in vitro and in vivo antimicrobial activity of the commercial Lactobacillus acidophilus (L. acidophilus) cells and cell free extract against Aeromonas hydrophila (A. hydrophila). The in vitro method was carried out using well diffusion method. For in vivo evaluation, the effect of L. acidophilus on the survival rate of Pangasianodon hypophthalmus (P. hypophthalmus) infected with A. hydrophila was evaluated. The well diffusion method showed a significant inhibition ability of L. acidophilus cells against A. hydrophila compared to the cell free extract. The inhibition diameters obtained with cells and cell free extract were 17.23 mm and 15.17 mm, respectively. P. hypophthalmus injected with L. acidophilus cells and cell free extract following challenged with A. hydrophila cells showed survival rate of 70% and 60% respectively, at 2-week post challenged. The gas chromatography-mass spectrophotometry (GC-MS) result revealed that a diverse of compounds was detected in both the L. acidophilus cells and cell free extract, among them the most abundant component was pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl), which showed a promising anticancerous activity and might be played a significant role in the recovery of the infectious P. hypophthalmus. The current study revealed that both cells and cell free extract of L. acidophilus have antimicrobial activity against A. hydrophila

Teachers need analysis: Development of the Urban Heat Island module based on a contextual approach

Since the nineteenth century, scientists have studied the Urban Heat Island (UHI). The negative effects of UHI could be mitigated with the help of interdisciplinary studies, but none have been performed so far. UHI research in schools has some holes that could seriously hinder students' grasp of climate change. The purpose of this research is to ascertain whether or not the Urban Heat Island module is necessary for enhancing students' understanding of climate change in the classroom. The Greater Solo Area Region's 72 geographic teachers were chosen at random for this study. Preliminary data on teachers' familiarity with UHI in the Greater Solo Area shows that, on average, they know very little about UHI. About 47 percent of the teachers surveyed had no understanding at all of UHI, while the remaining 25 percent had a moderate amount of knowledge, seven percent had high understanding, and three percent had very high understanding. Results from a test given to educators in both the suburbs and the city corroborated these observations. All teachers agreed that the UHI enrichment module created using a contextual approach was necessary as a supplementary medium for climate change material, as indicated by the results of the teacher needs assessment tests

Applications of next-generation sequencing technologies and computational tools in molecular evolution and aquatic animals conservation studies : a short review

Aquatic ecosystems that form major biodiversity hotspots are critically threatened due to environmental and anthropogenic stressors. We believe that, in this genomic era, computational methods can be applied to promote aquatic biodiversity conservation by addressing questions related to the evolutionary history of aquatic organisms at the molecular level. However, huge amounts of genomics data generated can only be discerned through the use of bioinformatics. Here, we examine the applications of next-generation sequencing technologies and bioinformatics tools to study the molecular evolution of aquatic animals and discuss the current challenges and future perspectives of using bioinformatics toward aquatic animal conservation efforts

Reproductive biology of estuarine catfish, Arius argyropleuron (Siluriformes: Ariidae) in the northern part of Peninsular Malaysia

A preliminary study on reproductive biology of estuarine catfish, Arius argyropleuron was conducted using samples collected from Merbok estuary which is located in the northern part of peninsular Malaysia. The fish samples were collected in March-December 2009 using a barrier nets deployed on mudflat opposite vegetation of mangroves. Testes and ovaries were classified base on volume relative to abdominal cavity, gonad forms, size of gonad, colors and oocytes diameter. The gonado-somatic indices showed that the fish matured throughout the year with major spawning peak for females occurred in April and minor peak in July, whereas males recorded a higher peak in November. Absolute fecundity of mature ovary was ranged from 19 to 87 eggs and was linearly related to fish length and power function to fish body weight. Three groups of eggs for the ovary in stage II and two groups in stage III were recorded. The length at first maturity for both males and females was approximately 22.5 cm in fork length. Keywords: Arius argyropleuron, Merbok estuary, peninsular Malaysia, reproductive biolog

Evidence of geographical structuring in the Malaysian Snakehead, Channa striata based on partial segment of the CO1 gene

Channa striata, locally known as “haruan”, is economically important in fisheries and aquaculture industries in several Asian countries. DNA sequencing, based on a partial segment of the Cytochrome oxidase c subunit 1 (CO1) gene, was used to determine genetic variation in C. striata samples from four different populations on the west coast of Peninsular Malaysia. The highest nucleotide and haplotype diversities were observed in the Linggi population (π = 0.0067, h = 0.835), and the lowest in the Timah Tasoh population (π = 0.0008, h = 0.286). Apart from Kajang-Linggi, which was insignificant, FST values were significant (p < 0.05) in all pairwise-population comparisons. Consequently, it is inferred that genetic structuring C. striata populations in this region was largely shaped by a common origin, with secondary influences from geographical factors and isolation

Effect of dietary prebiotics and probiotics on snakehead (Channa striata) health : Haematology and disease resistance parameters against Aeromonas hydrophila

This study examined the effect of dietary prebiotics and probiotics after 16 weeks, followed by 8 weeks of post feeding trial with the control unsupplemented diet on haematological and immune response against Aeromonas hydrophila infection in Channa striata fingerlings. Fish were raised on a 40% protein and 12% lipid feed containing three commercial prebiotics (β-glucan, GOS or galacto-oligosaccharide, MOS or mannan-oligosaccharide); and two probiotics- (Saccharomyces cerevisiae, Lactobacillus acidophilus), respectively and a control. Throughout the study, supplementation with dietary prebiotics and probiotics led to significant (P < 0.05) improvement in the red blood cells, white blood cells, packed cell volume, haemoglobin concentration and serum protein level and lysozyme activities; and these improvements were effective significantly (P < 0.05) when the fish were challenged with Aeromonas hydrophila at the dose of 2×106. The disease resistance against A. hydrophila was higher significantly (P < 0.05) in fish fed with probiotic feed supplements (L.acidophilus was highest) compared to prebiotics and control. The study is the first to report the absence of differences in sustaining the efficacies attained afterintakeofβ-glucan, GOSandMOSuponpost-feeding withanunsupplemented feed, over a prolonged period

Length-weight Relationships of Some Important Estuarine Fish Species from Merbok Estuary, Kedah

Merbok estuary, located in the northern part of Peninsular Malaysia, was inhibited by 81 species that are representatives of 45 genera and 36 families of fish. The length-weight relationship of 23 fish species belonging to 18 families was presented. The b values varied between 2.7928 for Butis gymnopomus and 3.6001 for Sillago sihama. Nine species exhibited positive allometric growth, 10 species were negative allometric growth, 3 species had isometric growth and 1 species was Gompertz form of growth. The length-weight relationships for some species from the Merbok estuary are hereby publish for the first time, and most of the fish specimens were juveniles. Keywords: Estuarine fishes, length, weight, fisheries management, Merbok estuar