Influences of environmental parameters and phytoplankton productivity on benthic invertebrates in a tropical oligotrophic lake, northern Malaysia

Studies that associate environmental parameters with aquatic organisms in man-made lakes remain limited by accessibility and interest particularly in many Asian countries.Withmissed opportunities to monitor environmental transitions at Lake Kenyir, our knowledge of lake transition is restricted to the non-mixing shallow waters only. Triplicate monthly benthic invertebrate samples were collected concurrentlywith various environmental parameters at three locations (zonesA–C) of Kenyir Lake,Malaysia. Our results affirmed that the northeast part of Lake Kenyir is oligotrophic. Abundance of phytoplankton, total suspended solids, phosphate, nitrite and nitrate drive the abundance of various groups of benthic invertebrates. All of these extrinsic variables (except phosphate) negatively influenced the density of Trichoptera and positively influenced (P<0.05) the densities of Polychaeta, Oligochaeta, Bivalvia, Gastropod, Isopoda and Copepod in all zones. Phosphate negatively influenced the density of Trichoptera and positively influenced (P<0.05) the densities of Oligochaeta, Bivalvia and Copepod. Its influences on the Polychaeta, Gastropod and Isopoda densities were zone-specific. Overall, seasons equally influenced the relationships between extrinsic and response variables in all zones. The results of this study are useful to evaluate the lake’s environmental quality, in conservation and in similar projects involving environmental handling, monitoring and recovery

Citizen science frontiers horseshoe crab population regain at their spawning beach in East Peninsular Malaysia

Carcinoscorpius rotundicauda and Tachypleus gigas may co-exist and share common spawning grounds elsewhere but at Balok (East Coast of Peninsular Malaysia), C. rotundicauda is an understudied species. Neglected as research candidate because of inaccessible spawning grounds, smaller size and less commercial value than T. gigas and also, difficulty to attain from the wild has made C. rotundicauda population status remaining unidentified at Balok. This standpoint drove the present attempt because anthropic activities like structure placement and mining are point-source for runoffs that load sediments into Balok River. While erosion-accretion events have altered Balok River width, the shore sediments in Balok Beach were transitioned between medium-fine and fine sand between years 2012 and 2016. Eventually by year 2016, the C. rotundicauda were depositing 5117 eggs in 91 nests from 200 to 1000 m range along this corridor facing South China Sea. From this yield, C. rotundicauda released 2880 eggs in 56 nests during the Southwest monsoon, 1254 eggs in 19 nests during the Northeast monsoon and 983 eggs in 16 nests during the Inter-monsoon seasons. Though female C. rotundicauda opted to lay their eggs in shallow burrows at lower shorelines, the absence of erosion and substantial silt and clay (>20%) deposition facilitates C. rotundicauda embryogenesis with brief periods of temperature and salinity shocks during day-time falling tides. This encourages C. rotundicauda to emerge with increasing abundance and carry out bi-monthly spawning at Balok Beach. In short, shore restoration initiatives like systematic boat docking, proper disposal of nets and waste and, periodic fish-catching operations were effectively led by the Balok fisher citizen scientist. This successful community joint-cooperation proves that citizen-led caretaking of degraded beaches offers marine life protection and are practical for coastal area management especially at areas where other oviparous animals such as turtles and crocodiles are harboured

Effects of shore sedimentation to tachypleus gigas (Müller, 1785) spawning activity from Malaysian waters

Ripraps, land reclamation and fishing jetty renovation were perturbing Balok Beach shores between the years 2011 and 2013 and visible impacts were scaled using horseshoe crab spawning yields. Initially, placement of ripraps at Balok Beach effectively reduced erosion and created a suitable spawning ground for the horseshoe crab, Tachypleus gigas. However sediments begun to gather on the beach onward year 2012 which increased shore elevation and caused complete shore surface transition into fine sand properties. This reduced sediment compaction and made Balok Beach less favourable for horseshoe crab spawning. During the dry Southwest monsoon, Balok River estuary retains more dense saline water which assists with sediment circulation at the river mouth section. Comparatively, the less dense freshwater during the wet Northeast monsoon channels sediments shoreward. Circa-tidal action that takes place at Balok River sorts the shore sediments to produce an elevated and steep beach. Hence, the reduced number of T. gigas nests and eggs retrieved during year 2013 (after comparing with yield of year 2012) at Balok Beach are indicating impacts from anthropic-caused sedimentation. Models need to be constructed and associated with T. gigas spawning-migration to fully understand sediment transport especially at coastal areas that need or are undergoing nourishment

Earlier denaturation of DNA by using novel ternary hybrid nanoparticles

Two novel ternary hybrid nanoparticles (THNp) consisting of graphene oxide (GO) and reduced graphene oxides (rGO) were added to samples of DNA. The effect of the addition of nanoparticles on the thermal denaturation of DNA samples was studied by measuring the absorbance using a temperature-controlled Perkin Elmer UV spectrophotometer. Adding GO-TiO 2-Ag and rGO-TiO 2-Ag nanoparticles lowered the denaturation temperature of template DNA significantly. The nanoparticles affect the denaturation rate. The optimal GO-TiO 2-Ag and rGO-TiO 2-Ag concentrations were found to be 5× 10-2, which resulted in 86-and 180-folds augmentation of DNA denaturation (6.5 µg/mL), respectively, while it resulted in 2-and 7-folds augmentation of DNA denaturation (11.5 µg/mL), respectively, at temperature as low as 80 C. The results indicated that rGO-TiO 2-Ag nanoparticles exhibited significantly higher DNA denaturation enhancement than rGO-TiO 2-Ag nanoparticles, owing to their enhanced thermal conductivity effect. Therefore, these nanoparticles could help to get improved PCR yield, hence enable amplification to be performed for longer cycles by lowering the denaturation temperatur

A review of durian plant-bat pollinator interactions

Durian (Durio zibethinus) brings in princely revenue for the fruit economy in Southeast Asia, ushering the current trend of clearing forests for durian plantations. Despite the thorny fruit’s popularity and increasing bat-durian papers, not many associate their vital plant-pollinator relationship. This unfamiliarity has led to the persisting negative connotations of bats as agricultural pests and worse, a disease carrier amplified by the Covid-19 pandemic. This review focuses on the bat-durian relationship comprising botanical insights and pollination ecology in relevance to the wider pteropodid-plant interactions. The majority of the studies compiled have concluded that bats are the most effective pollinator for durian than insects. Six fruit bat species (Chiroptera: Pteropodidae) have been recorded pollinating durian flowers, with several other pteropodid species speculated to pollinate durian, including in non-native countries. Lastly, we address the research gaps for the batdurian relationship, which can also be applied to other chiropterophilous plants

Membrane retention potential of Tachypleus gigas during early embryogenesis

Investigation on metal ion (Cd2+ and Pb2+) retention within the embryonic shell of Tachypleus gigas embryos was investigated. Inductively coupled plasma optical emission spectrometry was used for metal observations whereas developmental abnormalities were observed using a scanning electron microscope and histology via Harrison-Eosin staining. Metal ions penetrate and regulate between the extra- and embryonic shell environments to cause delayed embryogenesis only in early embryonic stages (Stages-E and DE). Ionic regulation was studied and findings showed that the embryonic shell (ES) was capable of selecting required ions whereas the extra-embryonic shell (EES) having higher retention potential. Throughout the 34 d of exposure, Se2+ was accumulated in the yolk mass (YM). Ionic regulation of embryos was influenced by stocking density and concentration of metabolites. Bioaccumulation factor revealed accumulation potential as EES > ES > YM and thus EES is suitable for biological membrane development. The mechanism of ionic regulation in the ES membrane can be used as a model to design a biological membrane capable of removing metals from polluted waters

Fish as bio-indicator tool for assessing estuarine health

Fish Health Index and Index of Biotic Integrity directly indicates environmental health and was used in our monitoring at Coleroon, Vellar and Uppanar, estuaries in the southeast coast of India. The use of cast nets revealed 104 species of fish that belongs to 69 genera, 44 families and 10 orders. Assessment using fish health index at Coleroon, Vellar and Uppanar estuaries produced scores of 4.8692, 8.4981 and 1.4042 which means Vellar has better health than Coleroon and Uppanar. In addition, 12 metrics were used to produce the index of biotic integrity where total scores varied from 18 to 51. With Vellar achieving higher scores than Coleroon and Uppanar estuary, a Two-way ANOVA was employed to validate the data with significant achievement (P&lt;0.005). Therefore, we can safely associate Coleroon, Vellar and Uppanar with ‘Fair’, ‘Good’ and ‘Very poor’ grades. Also, visual depiction of Vellar demarcates it as pristine in comparison to Coleroon and Uppanar that are subject to impairments along with dominance of omnivorous fishes. Knowledge from this study eases monitoring of important estuaries particularly for food security so that management sustains community livelihood

Avian data from Kenyir rainforest trail

This data article is constructed using avian (bird) counts from a recently identified trail in Kenyir rainforest, East Peninsular Malaysia. Avian chirps and naked eye visual were simultaneously used to locate the birds. After visual binocular and digital image inspection, identification of avian species were carried out using reference books. Data tabulation are divided by monsoon seasons and months before interpret using Shannon and Evenness indices. The highlights like feeding guilds, nativity, iconic species and statuses in the wild are presented with the data to increase its value. Within these, a total of 457 avian individuals from 36 avian family groups were recorded from which, 25 of these avian species occur as near threatened, vulnerable, endangered and critically endangered in the wild. Having these, the tabulated data becomes a calendar for seasonal availability of avian species which considers the 1.0 km trail suitable for bird watching, scientific study and ecotourism purposes

The final spawning ground of Tachypleus gigas (Müller, 1785) on the east Peninsular Malaysia is at risk: a call for action

Tanjung Selongor and Pantai Balok (State Pahang) are the only two places known for spawning activity of the Malaysian horseshoe crab - Tachypleus gigas (Müller, 1785) on the east coast of Peninsular Malaysia. While the former beach has been disturbed by several anthropogenic activities that ultimately brought an end to the spawning activity of T. gigas, the status of the latter remains uncertain. In the present study, the spawning behavior of T. gigas at Pantai Balok (Sites I-III) was observed over a period of thirty six months, in three phases, between 2009 and 2013. Every year, the crab’s nesting activity was found to be high during Southwest monsoon (May–September) followed by Northeast (November–March) and Inter monsoon (April and October) periods. In the meantime, the number of female T. gigas in 2009–2010 (Phase-1) was higher (38 crabs) than in 2010–2011 (Phase-2: 7 crabs) and 2012–2013 (Phase-3: 9 crabs) for which both increased overexploitation (for edible and fishmeal preparations) as well as anthropogenic disturbances in the vicinity (sand mining since 2009, land reclamation for wave breaker/parking lot constructions in 2011 and fishing jetty construction in 2013) are responsible. In this context, the physical infrastructure developments have altered the sediment close to nesting sites to be dominated by fine sand (2.5Xφ ) with moderately-well sorted (0.6–0.7σφ), very-coarse skewed (−2.4SKφ), and extremely leptokurtic (12.6Kφ) properties. Also, increased concentrations of Cadmium (from 4.2 to 13.6 mg kg−1) and Selenium (from 11.5 to 23.3 mg kg−1) in the sediment, and Sulphide (from 21 to 28 µg l−1) in the water were observed. In relation to the monsoonal changes affecting sheltered beach topography and sediment flux, the spawning crabs have shown a seasonal nest shifting behaviour in-between Sites I-III during 2009–2011. However, in 2012–2013, the crabs were mostly restricted to the areas (i.e., Sites I and II) with high oxygen (5.5–8.0 mg l−1) and moisture depth (6.2–10.2 cm). In view of the sustained anthropogenic pressure on the coastal habitats on one hand and decreasing horseshoe crabs population on the other, it is crucial to implement both conservation and management measures for T. gigas at Pantai Balok. Failing that may lead to the loss of this final spawning ground on the east coast of P. Malaysia

Episodic human activities and seasonal impacts on the Tachypleus gigas (Müller, 1795) population at Tanjung Selangor in Peninsular Malaysia

The scientific literature on population dynamics, breeding biology and nesting behaviour of the Asian horseshoe crabs is limited and still to emerge from several locations in South and Southeast Asia. The present study (2009-2011), aimed at observing the spawning activity of Tachypleus gigas (Müler, 1795) in relation to local environmental conditions, was carried out from Tanjung Selangor (Sites 1-3) on the east coast of Peninsular Malaysia. Southwest (SW) monsoon (May-September) was found to be more favourable (range, 456-1309 eggs) than Inter-monsoon (IM) (April and October) (169-317 eggs), whereas no eggs at the time of Northeast (NE) monsoon (November-March). Meanwhile, T. gigas preferred Site-1 (located close to River Pahang mouth) for its nesting in the SW and shifted to Site-2 and/or Site-3 (located 150-200 m interior) in the IM periods. This nest shifting behaviour of T. gigas was primarily associated with the seasonal water current that becomes intensive during NE monsoon. However, the human activities such as sand mining (2010), jetty (2010-2011) and road/bridge (2011 - present) constructions in the vicinity have affected the normal physicochemical conditions of the sediment/water. Importantly, the sediment being represented largely by medium sand with moderate sorting, symmetrical and very leptokurtic properties in 2009 was changed into coarse sand with poor sorting, fine/very fine skewed and extremely leptokurtic in 2010-11. In addition, the heavy metal contamination of Cadmium and Selenium in the sediment and Hydrogen Sulfide in the water increased considerably (2010-11). These changes, not only reduced T. gigas spawning activity/egg counts between 2009 and 2010 (from an average of 912 ± 690 to 360 ± 288) (±SD), but also correlated with its total absence during 2011 (PRIMER v.6). Since Tanjung Selangor beach (adjoining the Terus and Pahang Tua estuary) is one of the very few known spawning grounds for the Malaysian horseshoe crab (T. gigas), it is imperative to conserve and manage this area and it should be sanctioned as a 'Marine Protected Area'.SCOPUS: ar.jinfo:eu-repo/semantics/publishe