Freshwater fishes are species that spend their entire live in either freshwater inland or brackish estuaries. The checklist of the fish species should be updated consistently to ensure their diversity is preserved. The study of diversity and distribution of freshwater fishes at Sungai Muar, Kuala Pilah, Negeri Sembilan was carried out on 14 and 15 March 2020 to identify the fish diversity and their development in Sg. Muar, Negeri Sembilan. Trawl (fish collections), weighing machine and ruler (morphometric observations) was used during experiment. Fish species found during this study include Oreochromis mossambicus (Family Cichlidae), Hemibagrus nemurus (Family Bagridae), Homaloptera tweediei (Family Balitoridae), Notopterus notopterus (Family Notopteridae), Oxyeleotris marmorata (family Eleotridae), and five species of Family Cyprinidae, which were Mystacoleucus marginatus, Osteochilus haseltii, Cyclocheilichthys apogon, Barbonymus schwanenfeldii and Hampala microlepidota. Fishes from family Cyprinidae was dominated the area with a total of 102 individuals found. The statistical analysis shows the diversity (H’)=1.826, richness (R’)=2.004 and evenness (E’)= 0.5645 of freshwater fish at Sungai Muar, respectively. The most dominant species found was Mystacoleucus marginatus with 50 individuals and the least abundant species were Barbonymus schwanenfeldii, Homaloptera tweediei and Oxyeleotris marmorata with one individual only. The length-weight regression shows a positive allometric growth with ‘b’ value is higher than 3 at both stations; 3.0118 (Station 1) and 3.4409 (Station 2). It shows that the fish becomes heavier as its length increases. This data provides information about the fish habitat in Sungai Muar and can be used to update the checklist of fish species in Sg Muar. The data obtained provides information about the fish habitat in Sungai Muar which could be useful for the planning of fishing activities Other than that, it also important as a guideline for future research and conservation purposes especially in Negeri Sembilan.
Vibrio parahaemolyticus is a causative agent of foodborne outbreaks associated with the consumption of raw or under-cooked seafood. This study aimed to quantify and detect the occurrence of V. parahaemolyticus in freshwater fish by performing Most Probable Number (MPN) method in combination with Polymerase Chain Reaction (PCR). In this study, a total of 20 red tilapia (Oreochromis sp.) were collected from nearby local wet markets. Polymerase Chain Reaction (PCR) assay targeting the toxR gene in V. parahaemolyticus was performed, with the expected DNA amplification size of 368 bp. MPN analysis showed that the estimated microbial load of V. parahaemolyticus were more than 1100 MPN/g. The result of the PCR assay confirmed the presence of V. parahaemolyticus in 90% of the isolates. This positive detection elucidated the presence of food-borne bacteria in freshwater fish from local wet-market which may affect not only the health of fish stocks but also raise public health concerns.
The study of river water quality plays an important role in assessing the pollution status and health of the water bodies. Human-induced activities such as domestic activities, aquaculture, agriculture and industries have detrimentally affected the river water quality. Pinang River is one of the important rivers in Balik Pulau District that supplies freshwater for human consumption. A total of 442 physical and chemical parameters data of the Pinang River, Balik Pulau catchment were analysed to determine the sources of pollutants entering the river. Non-supervised artificial neural network (ANN) was employed to classify and cluster the river into upstream, middle-stream and downstream zones. The monitored data and non-supervised ANN analysis demonstrated that the source of nitrate was derived from the upper part of the Pinang River, Balik Pulau while the sources of nitrite, ammonia and ortho-phosphate are predominant at the middle-stream of the river system. Meanwhile, the sources of high total suspended solid and biological oxygen demand were concentrated at the downstream of the river.
Like many other countries, reservoirs in Malaysia are primarily built for various
functions such as hydroelectric power generation, drinking water supply, flood mitigation
and irrigation for agricultural purposes. Artisanal fisheries activities were also performed in
these reservoirs. The freshwater fish are a requisite source of protein for the rural
population. Consequently, the fish resources in reservoirs should be carefully maintained
at sustainable level. Present study elucidates the preliminary assessment on autecological
studies of beardless barb, Cyclocheilichthys apogon as a model of fish biota in Muda
Reservoir. This research investigates the growth pattern of C. apogon using length-weight
relationship and their condition factor. A total of 307 specimens were captured using cast
net for six consecutive months from March 2014 until August 2014. The growth coefficient
(b) from the length-weight equation (W = aLb
) for male and female of C. apogon were
3.150 and 3.185, respectively, indicating positive allometric growth. The condition factor
values of male and female of C. apogon were 1.023 ± 0.111 and 1.026 ± 0.100,
respectively, suggesting that C. apogon is in good condition in Muda Reservoir. The
paucity of research on the autecological study in the Muda Reservoir contributes to the
main reason of performing this research. The findings will serve as baseline information of
this species in Muda Reservoir, as well as for comparative study in the future.
Opisthorchiasis is endemic in parts of Southeast Asia, including the northern and northeastern regions of Thailand. In these regions, the transmission by fish intermediate hosts has received little attention. We investigated the intensity of Opisthorchis viverrini metacercariae (OV MC) in wild cyprinid fishes from five districts within the Nakhon Phanom Province, Northeast Thailand. Fishes were procured from local markets in five districts throughout three different seasons (hot, rainy and cold) between February 2018 and January 2019. The samples were identified, counted and weighed before metacercariae detection was performed via the artificial digestion method. A total of 2,149 freshwater fishes, representing 20 species were collected. The fish most commonly contaminated with OV MC were Anematichthys repasson and Hampala dispar. The intensity of OV MC in Nakhon Phanom was 0.23 OV MC/fish and varied among districts, ranging from 0.07 to 0.52. A low intensity of OV MC/fish (defined as <=1 cyst) was found in all three different seasons in the Nakhon Phanom Province; hot season (0.55), cold season (0.22) and the rainy season (0.13). The intensity of OV MC/fish was moderate (defined as >1 cyst) in the Renu Nakhon district (2.5) in the hot season. By fish species, H. dispar yielded the highest, with a moderate intensity of 2.1. In natural freshwater cyprinid fish in Nakhon Phanom, OV MC infection is endemic with intensity rates varying according to district, season and fish species.
The total lipid contents and the concentration of eicosapentaenoic (EPA) and docosahexaenoic
(DHA) fatty acid of fourteen selected marine, three freshwater fish species, four shellfish species and two selected canned fish species of East Coast of Peninsular Malaysia were determined. The fat content of all samples ranged from 1.01 % to 15.83 % with silver catfish reported to have the highest value. Most of the fish had fat amounts lower than 10% of their total weight. In general, DHA concentrations (50.50-165.21 µg/g) were significantly higher than EPA (11.12-55.38 µg/g) in all of the fish species analyzed. Among all marine fish species, the sixbar grouper recorded the highest concentration of DHA (165.21 µg/g) while barramundi had the highest concentration of EPA (55.38 µg/g). In conclusion, all fish and shellfish species are considered a good source of EPA and DHA, representing a very valuable essential nutrient for maintenance of human health.
The presence of 226 Ra in water is a great concern in human life since it can cause health risk to a certain extent. In the state of Kelantan, being known of its granitic area, there is a lack measurement of 226 Ra content in river water, since water is the major source of water supply. According to the INTERIM National Water Quality Standards for Malaysia (INWQS), 226 Ra activity concentration in water cannot exceed 0.1 Bq/L. For this reasons, this research was planned to carry out a systematic measurement of water along Sungai Kelantan. Liquid Scintillation Counting was used for measurement of 226 Ra in water samples from Sungai Kelantan mainly in district of Kuala Krai. In this paper, the results obtained is about 26 water samples, filtered and unfiltered, collected along Sungai Lebir, Sungai Sok and Bukit Sabah. Thus, the assessment activity concentration of 226 Ra in river water was obtained as well as annual effective dose for consumption of drinking water.
A three-dimensional Regional Ocean Modelling System is used to study the tidal characteristics and their dynamics in the Sunda Shelf of the southern South China Sea. In this model, the outer domain is set with a 25 km resolution and the inner one, with a 9 km resolution. Calculations are performed on the inner domain. The model is forced at the sea surface by climatological monthly mean wind stress, freshwater (evaporation minus precipitation), and heat fluxes. Momentum and tracers (such as temperature and salinity) are prescribed in addition to the tidal heights and currents extracted from the Oregon State University TOPEX/Poseidon Global Inverse Solution (TPXO7.2) at the open boundaries. The results are validated against observed tidal amplitudes and phases at 19 locations. Results show that the mean average power energy spectrum (in unit m2/s/cph) for diurnal tides at the southern end of the East Coast of Peninsular Malaysia is approximately 43% greater than that in the East Malaysia region located in northern Borneo. In contrast, for the region of northern Borneo the semidiurnal power energy spectrum is approximately 25% greater than that in the East Coast of Peninsular Malaysia. This implies that diurnal tides are dominant along the East Coast of Peninsular Malaysia while both diurnal and semidiurnal tides dominate almost equally in coastal East Malaysia. Furthermore, the diurnal tidal energy flux is found to be 60% greater than that of the semidiurnal tides in the southern South China Sea. Based on these model analyses, the significant tidal mixing frontal areas are located primarily off Sarawak coast as indicated by high chlorophyll-a concentrations in the area.
This study was undertaken to analyze the efficiency of Botryococcus sp. in the phycoremediation of domestic wastewater and to determine the variety of hydrocarbons derived from microalgal oil after phycoremediation. The study showed a significant (p < 0.05) reduction of pollutant loads of up to 93.9% chemical oxygen demand, 69.1% biochemical oxygen demand, 59.9% total nitrogen, 54.5% total organic carbon, and 36.8% phosphate. The average dry weight biomass produce was 0.1 g/L of wastewater. In addition, the dry weight biomass of Botryococcus sp. was found to contain 72.5% of crude oil. The composition analysis using Gas Chromatogram - Mass Spectrometry (GC-MS) found that phthalic acid, 2-ethylhexyltridecyl ester (C29H48O4), contributed the highest percentage (71.6%) of the total hydrocarbon compounds to the extracted algae oil. The result of the study suggests that Botryococcus sp. can be used for effective phycoremediation, as well as to provide a sustainable hydrocarbon source as a value-added chemical for the bio-based plastic industry.
Stratified estuaries are home to expanding aquaculture activities whose ecological footprints can be observed through trends in microbial community respiration in the water column. Bottle incubations are widely used to measure water column community respiration in marine and freshwater ecosystems by measuring the flux of dissolved oxygen occurring in the bottle over a period of time. When in situ dissolved oxygen (DO) concentrations are markedly different than DO concentration of the incubation medium the potential for diffusion of oxygen across the bottle opening is great and may be especially pronounced in strongly stratified systems with relatively low rates of pelagic oxygen consumption. We incubated 60 Biochemical Oxygen Demand (BOD) bottles filled with sterilized water with DO concentrations ranging from 2.51 mg O2 L-1 to 10.03 mg O2 L-1 for 24 hours in a temperature controlled water bath. There was a significant relationship when DO flux was set as a function of initial DO (DO Flux = -0.0017x + 0.0085, r2 = 0.72, p < 2.2 e-16). DO fluxes ranged from -0.012 mg O2 L-1 hour-1 to 0.005 mg O2 L-1 hour-1 for bottles incubated with initial DO ranging from 10.03 mg O2 L-1 to 3.31 mg O2 L-1, respectively. These results suggest that diffusion across the ground glass seal of BOD bottles is possible and that extra precaution through parallel diffusion controls should be considered when measuring pelagic respiration using BOD bottle incubations in systems with relatively low or relatively high in situ DO concentrations.
Information on the spawning migration, spawning ecology and life history of tropical eels in the Indo-Pacific region is very limited. The physiological and morphological characteristics of tropical freshwater eels, Anguilla bicolor bicolor and A. bengalensis bengalensis collected in Malaysia were examined in relation to their downstream migration patterns. A total of 455 eels were collected over monthly intervals between February 2014 and January 2016 and we examined both gonadosomatic index and gonad histology features. In both species, close positive relationships between advanced maturation stages and eye, fin, gonadosomatic indexes were found in males and females. A. bengalensis bengalensis was found to be larger and heavier than A. bicolor bicolor at the time of seaward migration. The final stage of maturation for seaward spawning migration occurred throughout the year in A. bicolor bicolor, although that of A. bengalensis bengalensis was estimated to six months due to the limited number of samples. These results suggest that year-round spawning in the open ocean occurs in the tropical eel. This non-seasonal spawning ecology is notably different from that of temperate eels, which are known to follow a well-defined spawning season, with spawning migrations generally taking place during autumn months.
There are some signals that Malaysian marine landings are decreasing and that wild stocks have been over-fished. However, it has extensive inland water bodies which have the potentials to be developed into freshwater aquaculture sites. Tengas (Neolissochilus sp.), a freshwater type of fish, are found in abundance in Malaysia; but has not reached the commercial level in the market. This paper examines the potential of developing tengas as a commercial freshwater species. The data used in this study were obtained through primary data search from key informants and a survey. A semi-structured open-ended questionnaire with Malay and Chinese languages was designed for the interviews. The study areas covered Peninsular Malaysia and East Malaysia. From the survey, we found that tengas has potential to be taken as a food item and an ornamental fish. The wild stock of tengas in fact is also worthwhile to be conserved for agro-tourism development. Many restaurant operators are willing to invent cooking method on tengas.
A study of the heavy metal bio-accumulation by fresh water fish, Tilapia nilotica around Lohan Dam was carried out in aquarium system. The study showed that the fish tissues cultured in contaminated water samples, (location S3 and 54) contain higher heavy metals concentration compared with the fish cultured in uncontaminated water samples (S1 and S2). The concentrations of Fe, Zn, Mn, Cu, Ni and Cr in fish tissues are higher compared with those of Co, Cd and Pb. The bio-accumulation rates of Zn, Mn, Cu, Ni and Co are 25 times higher than those of the base levels and 10 times higher than those of the controls. The heavy metal bio-accumulation order in T. nilotica is as follows: Mn> Cu> Cr> Ni> Co> Zn> Pb> Cd> Fe. The heavy metal intakes by fish during the experimental period did not exceed the level concentration levels.
Kajian bioakumulasi logam berat oleh ikan air tawar, Tilapia nilotica di perairan sekitar Empangan Lohan dilakukan dengan kaedah ternakan akuarium. Hasil kajian menunjukkan tisu ikan yang diternak dalam sampel air tercemar (lokasi S3 dan S4) mengandungi logam berat yang lebih tinggi dari tisu ikan yang diternak dalam sampel air tidak tercemar (lokasi S1 dan S2). Kepekatan logam berat seperti Fe, Zn, Mn, Cu, Ni dan Cr didapati tinggi dalam tisu ikan berbanding dengan kepekatan Co, Cd dan Pb. Kadar bioakumulasi logam berat daIam ikan didapati tinggi bagi Zn, Mn, Cu, Ni dan Co yang masing-masing melebihi 25 kali ganda dari paras asal dan lebih 10 kali ganda dari paras kawalan. Siri bioakumulasi logam berat yang dikaji dalam ikan T. nilotica menurut urutan; Mn> Cu> Cr> Ni> Co> Zn> Pb> Cd> Fe. Kepekatan logam berat yang dapat diambil oleh ikan dalam masa kajian tidak mencapai nilai yang dapat menyebabkan kematian kepada ikan.
Lymphocystis disease (LCD) in fishes is caused by the agent called lymphocystis disease virus (LCDV). LCDV is a chronic and benign virus. The disease affects 96 species of marine and fresh water fishes ranged among 34 families in the world. Affected fish with LCD has a typical external symptom with clusters consisted of enormously hypertrophied dermal cells on the skin and fins. The hypertrophied cells, generally named lymphocystis cells, have a thick hyaline capsule, an enlarged nucleus and prominent basophilic cytoplasmic inclusions. Among the four species of fishes, olive flounder Paralichthys olivaceus, and rockfish Sebastes schlegeli were marine cultured fish, and gourami Trichogaster leeri and painted glassfish Channa baculis were freshwater ornamental fish. Although LCD causes low mortality, the disfigurement of infected fish can make them unsellable. Thus LCD has resulted in an important economic loss in the aquaculture industry. This study of histopathology may be adequate for a presumptive diagnosis of lymphocystis diseases both in marine and freshwater fish species.
A comparative study on the fatty acids contents of three Malaysian marine fishes Tenualosa toli (Terubok), Rastrelliger kanagurta (Kembong), Stolephorus baganensis (Bilis) and three freshwater fishes Channa striatus (Haruan), Pangasius hypothalamus (Patin), Clarias macrocephalus (Keli) were carried out. Marine fishes showed more unsaturated fatty acids with 3, 4, 5 and 6 double bonds than in freshwater fishes. Two n-3 polyunsaturated fatty acids (PUFAs); eicosapentaenoic acid (EPA) and docasahaexaenoic acid (DHA) were found more in marine fishes PUFAs than in freshwater fishes. Based on the fatty acids content of DHA, EPA and arachidonic acid (AA), Stolephorus baganensis provides the best source of it (4.68%,10.5%, 4.68%) followed by Rastrelliger kanagurta (10.62%, 4.85%, 3.17%) and Tenualosa toli (9.93%, 2.50%, 0.16%). However, freshwater fishes showed small range of DHA (0.63% - 1.41%), EPA (0.11% - 0.25%) and AA (1.41% - 4.46%). Saturated fatty acids palmitic was the major fatty acid found in all fishes studied.
Sperata aor is a freshwater catfish of Bagridae family which is distributed throughout Indian subcontinent including India, Bangladesh, Pakistan, Nepal and Myanmar. It is a popular food fish due to its good taste and high nutritional value. Recently it has also made its entry in domestic ornamental fish markets of India and has been reported to have moderate export price too. Earlier, few works on different aspects of its morphology and biology have been carried out but no consolidated review is available on these aspects. Therefore, the current work was done to sum up all available information on these aspects to fill the information gap that will be beneficial to its future fishery. Considering all available information, knowledge on food and feeding habit of this fish species is satisfactory, except detail information on spatial variation of its breeding periodicity, proper information on other aspects are still lacking. No work has been conducted to examine its captive culture potential or for induced breeding. Further work should be done to explore its future fishery.
Freshwater fish has been studied and reported numerously. However, little attention has been made and limited studies available on local marine fish in Malaysia. Thus, in this study, concentrations of heavy metals (Cd, Cr, Pb and Cu) were studied in four major local marine fish Megalaspis cordyla (hardtail scad), Rastrelliger kanagurta (Indian mackerel), Selaroides leptolepis (yellowstripe scad) and Sardinella fimbriata (fringescale sardinella). The study was also intended to estimate potential health risk assessment from these heavy metals to the consumption of fish and assess maximum allowable fish consumption rate. The range of heavy metal concentrations were 0.053-0.096 mg/kg for Cd, 1.16-2.34 mg/kg for Cr, 8.34-12.44 mg/kg for Pb and 1.40-3.21 mg/kg for Cu in four major self-caught saltwater fish. Heavy metal levels of Cd and Cu in the local marine fish from Port Dickson are below the limit enforced by Food Regulations (1985) while the levels of Cr and Pb have exceeded the limit. Potential health risks associated with Cd, Cr, Cu and Pb were assessed based on target hazard quotients. HQ values calculated for Cd, Cr and Cu were less than 1, thus indicate that no adverse effects while HQ values for Pb exceeded 1 for all the fish species assessed with the exception of Megalaspis spp and Sardinella sppa. Cr was the highest while Pb concentrations were the lowest in all the studied fish samples for maximum allowable fish consumption rate. A long term monitoring program is crucial to be done in coastal areas with high consumption of local marine fish along Port Dickson to obtain real consumption rates and other cofounders factors in local population.
The taxonomy of freshwater crabs requires a paradigm change in methodological approaches, particularly in investigations that use morphological techniques. The traditional morphometric approach (two-dimensional measurements) tends to be inappropriate for the identification of freshwater crabs due to their variable external morphology and lack of gonopods (conventionally used for the identification of male crabs) in females. In this study, we explore the potential use of the geometric morphometric technique for identification of female freshwater crabs, and identify taxonomic key characteristics of species. The shape of the carapace could be a good characteristic for the identification of female crabs, especially when the geometric morphometric technique is used. It was observed that the shape of the carapace has an advantage over the shape of the pleon and chela because its relatively flat orientation allows more consistent and easier data preparation for geometric morphometric analysis. The geometric morphometric technique is inexpensive, relatively less time consuming to employ, and accurate. This technique is convenient when dissection to examine the gonopods is not possible, which can damage the specimen in the case of endangered or rare species. Since the technique was used herein for only two species, more compelling and extensive evidence is needed before the reliability of the method can be proven.
Western Southeast Asia is hosting one of the world's most diverse faunas, and one of the reasons for this huge diversity is the complex geologic past of the area, increasing the frequency of isolation and expansion events over evolutionary time scale. As an example case, the present study reveals the phylogeny and biogeographic history of the Paracanthocobitis zonalternans species complex, small benthic freshwater fish (Teleostei: Nemacheilidae) that are commonly occurring across western Southeast Asia (from central Myanmar through western and southern Thailand to northern Malaysia). The group is particularly interesting since it occurs in three biogeographic subdivisions (Indian, Indochinese, Malay/Sundaic) and across all of the major biogeographic barriers in the region. Basing on mitochondrial and nuclear sequence data of 93 samples from about 50 localities we found six major clades, most with exclusive geographic distribution. Divergence time dated the origin of the P. zonalternans species complex to early Miocene (17.8 MYA) and a biogeographic analysis identified the Tenasserim region as the ancestral region. From this region the fish spread during periods of lowered global sea level, particularly during late Miocene (11-8 MYA) northwards into all Burmese river basins and southwards into south Thailand and northern Malaysia. Besides lowered global sea level periods, local stream capture events allowed the complex to expand, e.g. into the Mae Klong basin. Strong fragmentations during periods with elevated sea level during the Pliocene and Pleistocene repeatedly restricted populations to refuges and shaped the observed major lineages. Our results document a higher diversity within the P. zonalternans species complex than formerly believed and a strong impact of global sea level on its evolutionary history. Low sea levels promoted dispersal and elevated sea levels fragmentation events. A very similar impact of sea level changes can be expected in all stationary fauna (freshwater and terrestrial) in all non-mountainous coastal regions worldwide.
The evaluation of the importance of having accurate and representative stations in a network for river water quality monitoring is always a matter of concern. The minimal budget and time demands of water quality monitoring programme may appear very attractive, especially when dealing with large-scale river watersheds. This article proposes an improved methodology for optimising water quality monitoring network for present and forthcoming monitoring of water quality under a case study of the Selangor River watershed in Malaysia, where different monitoring networks are being used by water management authorities. Knowing that the lack of financial resources in developing countries like Malaysia is one of the reasons for inadequate monitoring network density, to identify an optimised network for cost-efficiency benefits in this study, a geo-statistical technique coupled Kendall's W was first applied to analyse the performance of each monitoring station in the existing networks under the monitored water quality parameters. Second, the present and future changes in non-point pollution sources were simulated using the integrated Cellular Automata and Markov chain model (CA-Markov). Third, Station Potential Pollution Score (SPPS) determined based on Analytic Hierarchy Process (AHP) was used to weight each station under the changes of non-point pollution sources for 2015, 2024, and 2033 prior to prioritisation. Finally, according to the Kendall's W test on kriging results, the weights of non-point sources from the AHP evaluation and fuzzy membership functions, six most efficient sampling stations were identified to build a robust network for the present and future monitoring of water quality status in the Selangor River watershed. This study proposes a useful approach to the pertinent agencies and management authority concerned to establish appropriate methods for developing an efficient water quality monitoring network for tropical rivers.