Spatial distribution of tropical estuarine nematode communities in Sarawak, Malaysia (Borneo).

Limited information is available on marine nematode assemblages from Malaysian waters. Field sampling was conducted at the river mouths of 10 estuaries along the coastline of Sarawak (Malaysia) in Borneo to determine the distribution pattern of marine nematode assemblages. Physico-chemical parameters were also recorded to determine if distribution of nematodes was correlated with salinity, temperature, dissolved oxygen, and pH. Overall, the sampled sites were characterised by low density and low diversity of nematodes. Multidimensional scaling (nMDS) and dendrogram showed high dissimilarity in species distribution. BioEnv recorded a low positive correlation between marine nematode species densities and environmental parameters (pH and particle fraction: silt). Functional feeding group (FFG) changed from the north to south suggesting adaption by marine nematodes to food availability. Daptonema tenuispiculum, Sabatieria praedatrix group and Terschellingia longicaudata were dominant in several study sites. In conclusion, a total number of 49 species of marine nematodes were recorded (excluding two freshwater species from the order Dorylaimida). Low densities and diversities together with the proportion of the functional feeding groups between the 10 study sites indicated a stressful environment for nematodes and nematode communities could potentially be used for future pollution assessment of estuarine habitats

An Ecological Study of Free-living Marine Nematodes in Teluk Awar, Sarawak, Malaysia

The community structure of marine nematode assemblages in the southern west of Borneo was investigated with special focus on the horizontal distribution from high tide to subtidal area. A transect study had been conducted in Teluk Awar. Nine stations were chosen from the Mean High-Water Neap to Mean Low Water Neap level. The physico-chemical characteristic of water and sediments were determined both ex situ. One-way ANOVA showed that the environmental variables among stations were significantly different (except chlorophyll and total organic matter). Multi-dimensional scaling demonstrated three distinct patterns among the stations while dendrogram showed high dissimilarity percentage in the species distribution among stations. In conclusion, the results showed that environmental variables such as clay, total organic matter and temperature were affecting the nematode distribution pattern in Teluk Awar

A New Record from East Malaysia: Sphaerolaimus macrocirculus (Nematoda)

A new record of Sphaerolaimus macrocirculus (Filipjev 1918) in East Malaysian coastal water was described. The species was isolated from the muddy area of Muara Tebas, Sarawak, Malaysia. A total of 47 species of Sphaerolaimus have been reported worldwide. Samples of Sphaerolaimus macrocirculus were previously recorded in the sublittoral mud area of temperate country. S. macrocirculus possesses a stout body (1.1 – 1.6 mm; De Man ratios: a (body length/body width) = 16.8 – 27.5; b (body length/oesophagus length) = 2.3 – 4.3; c (body length/tail length) = 5.6 – 8.6). The circular amphid is very clear and situated at the base of the cephalic capsule. In male, the amphid ranged from 11.3 – 14.3 µm in diameter (mean = 12.7 ± 1.3) and 0.4 c.d. (corresponding diameter). In female, the amphid ranged from 7.2 – 9.4 µm in diameter (mean 7.8 ± 0.9) and 0.2 c.d. The species is characterised by the presence of eight groups of subcephalic setae at the head region and three longer terminal setae

An Ecological Study of Free-living Marine Nematodes in Teluk Awar, Sarawak, Malaysia

The community structure of marine nematode assemblages in the southern-west of Borneo was investigated with special focus on the horizontal distribution from high tide to subtidal area. A transect study had been conducted in Teluk Awar. Nine stations were chosen from the Mean High Water Neap to Mean Low Water Neap level. The physico-chemical characteristic of water and sediments were determined both ex situ. One-way ANOVA showed that the environmental variables among stations were significantly different (except chlorophyll a and total organic matter). Multi-dimensional scaling demonstrated three distinct patterns among the stations while dendrogram showed high dissimilarity percentage in the species distribution among stations. In conclusion, the results showed that environmental variables such as clay, total organic matter and temperature were affecting the nematode distribution pattern in Teluk Awar

Free-living nematodes in Sarawak coastal waters

The taxonomic study on free-living nematodes had been carried out in Sarawak coastal waters to clarify the systematic and distribution of nematodes in Sarawak. This is the first taxonomic study conducted in Sarawak. A total of one hundred and eleven (111) species, representing forty seven (47) genera and twenty (20) families were identified from twenty four study sites along the Sarawak coastal waters. All species are first recorded in Sarawak, and were grouped according to their habitat (sediment type) of the station under study. All species were described and illustrated with detailed taxonomic notes and discussions. Pictorial keys of identification for species were also produced

Relationship between environmental variables and Marine Nematode densities in Teluk Awar, Sarawak Malaysia

A pilot study was carried out in Sarawak on the community structure of free-living marine nematode. The aim of this study was to determine the horizontal distribution of marine nematode associated with abiotic and biotic environmental factors. One-way ANOVA showed significant differences in the environmental variables (salinity, pH, dissolved oxygen, temperature, total organic matter) for both study transects. Chlrophyll a only showed significant difference in transsect A

A checklist of free-living marine Nematodes along Sarawak Coastal waters

The exploration and studies on marine meiofauna such as nematodes are still at its infancy stage in Sarawak. Few detailed studies had been conducted on marine nematodes up to species level. The aim of this study is to establish a database for marine nematodes in Sarawak. This study was carried out at 15 sampling sites along the Sarawak coastal waters. A total of 93 nematode species were recorded (19 families, 38 genera and 5 suborder). Xyalidae was represented by 16 species, followed by Desmodoridae (9 species) and Cyatholaimidae (8 species). A total of 93 species of free-living marine nematodes were documented along the Sarawak coastal waters