No abstract

In this paper, we studied some biological aspects of big eye scad (Selar crumenophthalmus) from Maldives. The fish sample was collected from the local fish market at Bangaa Faru, Male, Maldives. The length of the samples were ranged from 7.7 cm to 24.5 cm (mean value = 16.85 ± 2.82 cm) in fork length. Body weight ranged between 8 g to 255.6 g (mean value = 87.76 ± 40.41 g). The exponent values (b slope) of lengthweight relationship of S. crumenophthalmus are 2.9838 for females and 2.7687 for males; indicating negative allometric growth pattern for both sexes. Synchronous reproductive behaviour was observed in both sexes and a pronounced peak of Gonadosomatic index was observed in females in January 2013. It is estimated that length at first maturity (L50) for females is at 19.39 cm FL and for males at 21.76 cm FL. Our result also suggest that big eye scad have a reduced swimming capability, resulting the species to be easily caught. Careful planning and management should be implemented to prevent the big eye scad from being overfished.

The importance of terrestrial insects as food items for freshwater fish was studied by examining stomach contents of Devario regina (Fowler 1934)

An investigation study was conducted in Bukit Merah Reservoir (BMR) for the assessment of arsenic concentration in the surface sediment in 23 sampling stations. The sediment samples were digested and analysed for arsenic using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Sediment parameters such as pH (4.42 ± 0.71), redox potential (121.77 ± 42.45 mV), conductivity (205.7 ± 64.07 μS cm–1) and organic matter (25.35 ± 9.34%) were also examined. The main objectives of this study are to determine the arsenic distribution and concentration and at the same time to assess the enrichment of arsenic using the geoaccumulation index (Igeo) and enrichment factor (EF). This study shows the total arsenic concentration in the surface sediment of BMR is 4.302 ± 2.43 mg kg–1 and found to be below the threshold value of Canadian Interim Sediment Quality Guidelines (ISQG). High arsenic concentration is recorded near the southern part of the lake where anthropogenic activities are prevalent. Based on Igeo, 13% of sampling stations are categorised as moderately polluted, 52.2% as unpolluted to moderately polluted and the rest is categorised as unpolluted. EF shows 78.3% stations are classified as extremely high enrichment and the rest as very high enrichment. This finding provides important information on the status of arsenic contamination in BMR and creating awareness concerning the conservation and management of the reservoir in the future.

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. This 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. This 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.

Red seaweed Gracilaria sp. is known as ‘Janggut Duyong’ by the local people of Sarawak. This macroalgae iswell-distributed in both temperate and tropical seawaters. Gracilaria sp. could be processed to produce agar forindustrial purposes whereas some people consumed it directly and become part of their daily diet. In terms ofecology, Gracilaria sp. is one of primary producer in the seawater and its presence can form habitats to supportother aquatic organisms. Despite its socio-economic and ecological importance, little is known about Gracilariasp. in Sarawak. Hence, this study is designed to: (i) determine the diversity and abundance of Gracilaria in cageculture 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 beenconducted 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 invertebrateswere observed namely tunicates, bivalves, polychaetes, small crabs and brittle stars. The selected water qualityparameters 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 fornitrite (p= 0.588). However, the values recorded were within normal range of standard water quality for tropicalestuarine area. Since healthy population of Gracilaria could be easily found here, therefore this area has thepotential for future seaweed aquaculture.

Fish from three major rivers namely Pengkalan Chepa, Kelantan, and Galas rivers in Kelantan, Malaysia was caught using gill-nets with separate mesh sizes of 1, 2, 3, and 4 inches, respectively. There were 170 fish collected from the PCR systems, which represented 18 families and 21 species (2008-2009). The most common fishes, based on total fish captured, were Ikan duri (Arius maculatus) and Puyu (Anabas testudineus). A total of 245 individual fish were collected from KR (2010-2012) which comprised of 7 families and 22 fish species with the highest number of individual fish (51) collected during this survey was the spotted catfish (Arius maculatus). A total of 562 fish specimens representing 12 families and 32 species were captured from riverine monitoring in the GR systems (2008-2010).

Water quality profile of Pergau Reservoir or also known as Sultan Ismail Petra Hydroelectric Reservoir has been conducted from 28th October to 3rd November 2019 during Pergau scientific expedation 2019. Three (3) lentic sampling stations (P1, P2 and P3) were selected with eleven (11) water parameters such as water temperature, pH, biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), total dissolved solid (TDS), dissolved oxygen (DO), turbidity, ammonical-nitrogen, oil and grease (O&G), and total coliform were analyzed for water quality status of Pergau Lake. Stratification profile of DO, pH and water temperature were recorded by 10m depth at all lentic stations. Generally DO, temperature and pH reading at the surface lentic sampling stations ranging between 7.11 to 9.21 mg/L, 27 to 27.5 °C and 7.50 to 8.72, respectively. Anoxic layer was detected at depth of 9 m at P1 whereas 3 m at P2 and P3. Profiling of DO, pH and water temperature shown decreased pattern when the water depth increased. Others parameters such as COD at the subsurface were ranged from 1.3 to 1.4 mg/L, TSS reading recorded ranged from 4.00 to 6.80 mg/L, ammoniacal-nitrogen ranged from 0.05 to 0.07 mg/L whereas BOD5 were ranged from 1.3 to 1.4 mg/L. The Department of Environment – Water Quality Index (DOE-WQI) classification was used to assess the water quality status of the selected sampling locations. The results showed that all locations fall under Class I ranged between 92.66 to 94.55% and in summary the area can be classified as clean and suitable for sensitive aquatic organisms.