Taxonomy and some ecological aspects of meiobenthic harpacticoid copepods in coastal water of Peninsular Malaysia

A study on the taxonomy and some ecological aspects of meiobenthic harpacticoid copepods found in coastal water of Peninsular Malaysia was conducted from June 1996 to August 1999. The taxonomic study was carried out using specimens collected from Langkawi Island, Pangkor Island, Port Dickson, Tanjung Balau, Tanjung Piai and Redang Island. A total of 40 species, representing 29 genera from 16 families of harpacticoid copepods were identified. All the 40 species were unrecorded species in Malaysian coast. For all species, description, illustration and taxonomic notes were give The study on some ecological aspects of meiobenthic harpacticoid copepods was carried out along Port Dickson coast. Samples were obtained from the established transects perpendicular to the sea using a transparent hand corer with the inner diameter of3.57 cm. Harpacticoid copepods were the second dominant group of meiobenthos found in the studied areas. They contributed between 15% to 60% to total meiobenthos found in the sediment. The density and diversity distribution of meiobenthic harpacticoid copepods along the shore was correlated significantly (p<0.05) with certain environmental factors, namely salinity, dissolved oxygen, percentage of silt, clay and sand, water content, ground water level, depth of brown layer and sorting type of sediment. The vertical and horizontal zonation was correlated with the concentration of chlorophyll a in the sediment. The horizontal zonation was also correlated with the percentage of clay. The different set of environmental factors that found to correlate with the meiobenthic harpacticoid copepod distribution in the different studied areas indicated that different beaches might have their own environmental factors that governed the distribution

Effects of culture condition towards fatty acids in a harpacticoid copepod; Amphiascoides neglectus (Lang, 1965)

Copepods have been found as one of the best live feed in aquaculture. This study was carried out to determine the development time, growth performance and fatty acid content of a marine copepod, Amphiascoides neglectus, potentially become live feed for marine larval rearing. The laboratory experiments were designed to expose the population of A. neglectus to different sets of temperature, pH and salinity treatment. The copepods were maintained in the combination of salinity of 15, 25 and 35ppt, pH of 5,7,9 and temperature of 25, 28,35oC for 25days under hygienic condition. Fatty acid content was determined using gas chromatography method. The life cycle consists of six naupliar stages, five copepodite stages and an adult stage. Total development time of each life stages was from 9±3.61 h to 17 ±2.65 h and range from 53.86 µm to 593.98 µm in size. Nauplii, copepodites and adult stage showed highest population density when cultured in 28oC, salinity 25ppt and pH9 (T28P9S25). The bad growth performance was shown when they were cultured in 35oC, salinity 15 and pH5 (T35P5S15). A.neglectus cultured in T28P9S25 demonstrated the highest fatty acid contents with linoleic acid C18:2n-6 (LA), eicosapentaenoic acid C20:5n-3 (EPA), docosahexaenoic acid C22:6n-3 (DHA), arachidonic acid C20:4n-6 (ARA) and linolenic acid C18:3n-3 (LNA). The finding of this study could become the baseline for the optimum culture condition of A.neglectu

Comparison of horseshoe crabs (Tachypleus gigas) morphometry between different populations using allometric analysis

Studies on horseshoe crabs morphometrics found that they have maintained their descendent features from the Late Ordovician Period to present day. In the present study, we applied the allometric study to evaluate the correlation of body growth in three populations of the Asian horseshoe crab (Tachypleus gigas) collected from Balok (Pahang), Cherok Paloh (Pahang) and Merlimau (Melaka), Malaysia, coastal areas. The aims of this study are to examine the logarithmic growth of horseshoe crabs between three populations by analyzing the variation of their body weight (BW), carapace length (CL), carapace width (CW) and telson length (TEL) to determine their growth and maturity. Their body parameters were analyzed by the allometric method. There are no significant differences between males weight in all populations (p>0.05). However, females from Merlimau were smallest (BW: 519.7±66.3 g; CL: 21.1±1.1 cm; CW: 19.6±0.9 cm) among the three populations; Balok (BW: 928.5±123.2 g; CL: 23.8±1.0 cm; CW: 23.3±1.0 cm) and Cherok Paloh (BW: 939.8±125.7 g; CL: 25.4±1.5 cm; CW: 25.1±1.6 cm). Males and females of T. gigas in Merlimau could be classified as less matured among Balok and Cherok Paloh, since the increment of CL/CW were higher than their BW. Further study on T. gigas allometry along Malaysian coastal area is needed to understand the variation growth between populations. The study could be an alarming condition to a particular T. gigas population

DIVERSITY OF BIVALVES IN MANGROVE FOREST, TOK BALI KELANTAN, MALAYSIA

A study on the diversity and some ecological aspects that related to the abundance of infaunal bivalve species was done at Tok Bali mangrove, Kelantan, Malaysia. Samples and data collection was conducted during three different seasonal periods, on dry season (July), pre-monsoon (September) and monsoon (December) in the year 2005. Sampling stations were chosen in four mangrove forests which were encompassed with Rhizophora spp., Avicennia spp., Nypa fruticans and Mixed Mangrove. A collection of bivalve samples and sediment samples were done within 0.25 m2 quadrates and measurement of physico-chemical parameters were conducted using Hydrolab Quanta. Temperature, salinity and pH showed the normal mangrove value and decreased during monsoon, while dissolved oxygen show increasing during monsoon. Mean of grain size (ø) value ranged from 1.9 to 2.66 indicated that the sediment is fine sand. Mean TOM ranged from 0.67-1.45 g/g. A total of five (5) species of infaunal bivalves were observed, which were Polymesoda expansa, Marcia japonica, Gari ambigua, Pillsbryoconcha exilis and Donax faba. Diversity index H’ ranges from 0.72-1.27 and evenness index E’ ranged from 0.53-0.95 and richness index varied from 0.42-0.78. ANOVA tests showed that there were no significant differences for all biodiversity indices during dry, pre-monsoon and monsoon season (P>0.05). The results showed the low biodiversity of infaunal bivalves in the mangroves of Tok Bali. They could be more affected by the spatial factors rather than the monsoon. Long-term data collection is suggested to determine the seasonal pattern of their biodiversity and contribution to the mangrove ecosystem in the area

Seasonal variations of harpacticoid copepod and size-fractionated abundances in relation to environmental changes in Setiu Wetland

Aim: Harpaticoid copepods, an important component of fauna in marine environment, play a vital role in aquatic food webs as a source of food for other member of benthic community and the juveniles of predator fish species. Recent data on benthic plankton and nekton composition in coastal wetland of Setiu are useful and important in understanding the interaction between these organisms at different seasons. This maintains the diversity of fish in Setiu Wetland which is a major factor in developing the Wetland as a place for ecotourism and recreational fishing activity. The effort will directly or indirectly benefit the fisheries community living within the wetland which depends on the fisheries sector. Methodology: Meiobenthos samples were collected by Ponar grab. The samples were fixed in 10% formalin and 1% Rose Bengal. Content of each specimen bottle was filtered through 102 µm and 62 µm sieve shaker, respectively. Harpacticoid were individually hand sorted and counted under dissecting microscope. Data obtained for harpacticoid composition were analyzed using Kruskal-Wallis test. Results: Seasonal variation of harpacticoid composition for 100 µm sizes recorded the highest number during pre-monsoon with 3591.84 ind 10 cm-2 followed by monsoon, 2569.68 ind 10 cm-2 and post-monsoon 1545.84 ind 10 cm-2, respectively. Salinity is the main physical parameters that can be attributed to the plankton diversity and acts as limiting factor that influences the distribution of plankton community. Significantly, harpacticiod copepod steadily increased during post-monsoon with rising trend of salinity verified the environmental influences on zooplankton abundances. Interpretation: The results of this study indicated that different season demonstrated major impact on harpacticoid composition which may effect the avaibility of food source towards the small fishes as a live feed

Fatty acid composition in cultured Amphiascoides neglectus (Copepoda: Harpacticoida)

This study investigates the effect of salinity on the fatty acid profile of a harpacticoid copepod Amphiascoides neglectus exposed to constant laboratory lighting and temperature (25-26oC) at pH7 for 40 days. The results were compared with those cultured in the common open hatchery environment which is almost the same as in the natural ecosystem. Different fatty acid levels were determined using Gas Chromatography and Mass Spectrometry (GC-MS). Results showed that there were no significant differences (p>0.05) in fatty acid content for both 20ppt and 30ppt treatment but the percentage of EPA was higher in 20ppt. Harpacticoid copepods in the hatchery showed significantly (p<0.05) more fatty acids in 30ppt than 20ppt. EPA was also higher in harpacticoids cultured under 30ppt. Manipulation of salinity and temperature in combination of light factor for copepod rearing system could improve the deposition of fatty acids in their body

Report on five species of harpacticoid copepods from vegetative area of Sungai Pulai, Johor

Bottom vegetation is known as preferred habitat for many types of meiofauna such as copepods. The conditions of sea bottom that include vegetation could contribute to the copepod’s assemblage. Being an important diet for fish larvae, information on copepod species promotes effort for conservation of both fish species and marine ecosystem. Nonetheless, identification and taxonomic report on copepods from such areas are still scanty. Samples of copepods were collected by scrapping the uppermost 10cm of sediment of bottom area at Sungai Pulai’s seagrass-bed during low tide. Sediment was decanted to extract the copepods which later be preserved in 5% buffered formalin. Body parts were dissected under microscope and prepared for taxonomic study. All drawings made with the help of Lucida tube were used for comparison with established key of identification. Five families were noted in this study; Ameridae Monard, Lang, Parastenhelia Thompson & A. Scott, Dactylopusiidae Lang, Tisbidae Sars and Diosaccidae Sars. Harpacticoid copepod species described from this study were Ameira sp. (Ameridae Monard, Lang), Parastenhelia sp. (Parastenhelia Thompson & A. Scott), Paradactylopodia sp. (Dactylopusiidae, Lang), Idyanthepusilla (Tisbidae, Sars) and Stenhelia sp. (Diosaccidae Sars). Further study on functional morphology would explain their adaptability to both conditions of sea botto