Terrestrial insects as the main food for freshwater fish in Sungai Kerian tributaries: an implication on habitat conservation

The importance of terrestrial insects as food items for freshwater fish was studied by examining stomach contents of Devario regina (Fowler 1934) and its population parameters at canopied areas of selected tributaries of Sungai Kerian, in the northern state of Peninsular Malaysia. Ninety six percent (121 out of 126) of the fish stomachs examined contained food materials in the stomachs and the values of percentage of occurrence (%F), percentage numerical (%N) and percentage points (%P) indicated that collected fish ate similar food items in all rivers. Among the food categories, scavenging terrestrial ants (Formicidae) were the most dominant food item, hence the main diet for this species. The Index of Relative Importance (IRI) scores of food items indicated that ants were higher than other food items. This surface water feeder experienced a positive allometric growth (W = aLb) with a b (rate of growth) value of 3.256. Its asymptotic length, growth constant and growth performance index represented this species with a short life-span (L∞ = 10.90 cm, K = 1.20 year-1, φ’ = 2.15, tmax = 3 year, respectively) and had higher natural mortality (M = 2.40 year-1) than fishing mortality (F = 0.35 year-1) while the fish stock was underexploited (E = 0.13). The finding of this study indicated the importance of terrestrial ants as a food source that support excellent growth of D. regina and the need to conserve riparian trees along river banks to provide allocthonous materials and habitats for the ants

Red Seaweed Gracilaria Arcuata in Cage Culture Area of Lawas, Sarawak

Red seaweed Gracilaria sp. is known as ‘Janggut Duyong’ by the local people of Sarawak. This macroalgae is well-distributed in both temperate and tropical seawaters. Gracilaria sp. could be processed to produce agar for industrial purposes whereas some people consumed it directly and become part of their daily diet. In terms of ecology, Gracilaria sp. is one of primary producer in the seawater and its presence can form habitats to support other aquatic organisms. Despite its socio-economic and ecological importance, little is known about Gracilaria sp. in Sarawak. Hence, this study is designed to: (i) determine the diversity and abundance of Gracilaria in cage culture of Lawas, Sarawak (ii) assess the water quality of the cage culture area where Gracilaria is found and (iii) determine other aquatic organisms that found within Gracilaria population. Three field samplings had been conducted from October 2013 to November 2014 at cage culture areas of Awat-Awat Village, Lawas, Sarawak. Only single species of Gracilaria was found namely Gracilaria arcuata. Besides G. arcuata, Acanthophora sp. and Padina sp. were also found but in small patches. In addition, five different groups of aquatic invertebrates were observed namely tunicates, bivalves, polychaetes, small crabs and brittle stars. The selected water quality parameters namely temperature, pH, dissolved oxygen, salinity, turbidity, total suspended solid, orthophosphate, silicate and chlorophyll a were significantly different (p= 0.000) during all the three field samplings except for nitrite (p= 0.588). However, the values recorded were within normal range of standard water quality for tropical estuarine area. Since healthy population of Gracilaria could be easily found here, therefore this area has the potential for future seaweed aquacultur

Spatial and temporal variations of water quality and trophic status in Bukit Merah Reservoir, Perak

A study of spatial and temporal variations on water quality and trophic status was conducted twice a month from December 2012 to January 2014 in four sampling stations at Bukit Merah Reservoir (BMR). The concentration of dissolved oxygen (DO), water temperature, conductivity, total dissolved solids (TDS), total phosphorous (TP), PO4-, NO2-, NO3-, NH4+ and net primary productivity had significant differences temporally (p<0.05) except for pH, total suspended solids (TSS) and chlorophyll-a. Based on correlation analysis, the amount of rainfall and rain days has negatively correlated with secchi depth and chlorophyll-a (p<0.01). The water level has significantly decreased the value of the temperature, pH, conductivity, TP and NO2- but it has positive correlation with NO3- and NH4+. Discharged from Sungai Kurau increased the value of conductivity, TSS, TP and NO2- as a result from runoff and erosion, thus decreasing the secchi depth values, NO3- and NH4+. The water quality of BMR is classified in Class II and TSI indicates that the BMR has an intermediate level of productivity (mesotrophic) and meets the objective of this reservoir which was to provide water for paddy irrigation

Morphological Diversity of Gracilaria blodgettii Harvey 1853 (Gracilariaceae, Rhodophyta) from Sarawak, Malaysian Borneo

Gracilaria red algae are notable for their economic importance as agrophytes, sold as salad vegetable, and used as the base for selected food and nonalcoholic beverages. A wild population of Gracilaria exists in coastal areas of Sarawak, Malaysian Borneo, but there is only limited knowledge on species diversity and its abundance leaving the untapped economic potential of this resource. (is study was carried out to determine diversity of wild Gracilaria populations in Lawas, Santubong, and Asajaya, Sarawak, using the combination of morphological character examination and 5′region of the mitochondrial cytochrome c oxidase 1 (CO1-5P) gene analysis. Identification of the species using morphological characters revealed three species, namely, Gracilaria changii, G. blodgettii, and G. arcuata, had been collected from the sampling sites. However, based on 672 bp CO1-5P gene sequence analysis, all the three species were identified as G. blodgettii; besides, low genetic divergence values (0.17%–0.34%) were scored between samples in this study with the same species in GenBank. In the phylogenetic trees, all samples in this study group together with other G. blodgettii have high bootstrap values; thus, this species is monophyletic. (is study implies that species identification of Gracilaria and other seagrass taxa which have a phenotypic plasticity problem should include the CO1-5P gene analysis as it is a reliable gene marker for species diversity assessment

Morphological characteristics and habitats of red seaweed gracilaria spp. (gracilariaceae, rhodophyta) in santubong and asajaya, sarawak, malaysia

Red seaweed Gracilaria, one of the largest genus in Division Rhodophyta inhabits Sarawak coastal water. This study was designed to identify the species of Gracilaria using morphological approach and to assess selected water quality parameters in Gracilaria habitats. Three field samplings were carried out in Santubong and Asajaya, Sarawak from November 2013 to December 2014. Overall, three species were identified namely Gracilaria changii, G. blodgettii and G. coronopifolia, attached to net of cage culture in Santubong and root of mangrove trees in Asajaya. In addition, three different taxa of aquatic macroinvertebrates (polychaete, small crab, bivalve) and single species of red seaweed (Acanthophora sp.) were observed in Gracilaria assemblages. An estimate of 37% to 40% of the upper part of the cage net in Santubong was covered by seaweeds and only 16% to 20% in Asajaya’s mangrove. The study had provided better information on identification of Gracilaria and their habitat in Sarawak. Future work involving DNA barcoding of each species is in progress. © Penerbit Universiti Sains Malaysia, 2018

Hydrology, water quality and trophic state of Pergau Reservoir, Kelantan, Malaysia

ABSTRACTTo acquire baseline data for a remote Pergau Hydroelectric Power Plant reservoir, a hydrological and water quality examination of feeder rivers and reservoir water was conducted in 2013. The water balance of the reservoir was determined, and gauging and sampling were carried out in dry and wet periods. Dilution gauging was used to estimate the feeder river discharge. The total water flow into the reservoir increases nearly fivefold between the dry and wet seasons, while river discharge increases two to fivefold. All of the river intakes had Class 1 NWQS water quality. The lake’s water quality was Class 1 up to the top 3 meters, but below that, at some places, the water quality deteriorated to Class II. In the dry season, the trophic status of Pergau Reservoir is eutrophic as measured by TP (59.21) and chlorophyll-a (52.36) and the TSI (SD) was 53.93 Eutrophication occurrences will cause serious limitations in water use applicability. This research contributes to the biogeographical and limnological understanding of the Pergau catchment, as well as laying the groundwork for more sophisticated hydro-ecological investigations. Anthropogenic activities, together with run-off from agricultural operations and the presence of algae, are some of the sources of contamination noted in the study. Stricter legislation, stricter enforcement of current standards, matching of non-technical and techno-social remedial actions, and education are among the recommendations made for the Pergau Reservoir’s protection

The diversity and distribution of fish at the port and urbanized areas of Pulau Pinang Strait, Malaysia

Marine fish in Malaysian waters are impacted by various stressors, including resource exploitation, urbanization and industrialization. Therefore, this study examines the fish diversity and distribution at five sampling stations with different natural processes and anthropogenic activities in the coastal waters of Pulau Pinang, Malaysia. A total of 669 fish specimens belonging to 47 species from 23 families were collected using drift nets in two sampling periods from October to November 2017 and October to November 2019. The fish abundance is determined based on the catch per unit effort, (CPUE ind/hour). Among the dominant families, Leiognathidae and Ariidae accounted for 21.22 and 14.44 of the total catch, respectively. Three fish species, namely, Eubleekeria splendens, Anodontostoma chacunda, and Pennahia anea, dominated the catches. The CPUE near the ongoing reclamation projects and landfill was lower than that of the port and industrial areas with mangrove estuaries. The dendrogram clearly differentiated the fish species composition between the reclamation sites and natural shorelines. Given no previous research on the fish distribution along the Pulau Pinang strait featuring different habitat types, this study therefore serves as a contemporary fish assemblage for future research and surveys