Induction of settlement and metamorphosis in the tropical oyster, crassostea belcher/ (sowerby), by neuroactive compounds.

Larvae of the tropical oyster Crassostrea belcheri set and metamorphosed when exposed to epinephrine (EPI), norepinephrine (NE), L-3,4-dihydroxyphenylalanine (L-DOPA) and gamma-amino butyric acid (GABA). The optimum concentration of these neuroactive compounds was 10-5 M when larval set increased from 20% in the controls to between 60-80%. Larval setting performances were generally depressed when exposure was extended to 24 hours compared to 1 hour

Cheilostome Bryozoa from Penang and Langkawi, Malaysia

Twenty-three species of cheilostome bryozoans are described from the Malaysian islands of Penang and Langkawi based on a brief reconnaisance survey of shore localities. These are the first bryozoans to be formally described from either island and they demonstrate the potential for further research on these neglected suspension feeders. Of the 23 species recorded, 12 are anascans, half of which are malacostegines, and 11 are ascophorans. The new combinations Acanthodesia falsitenuis (Liu, 1992), A. perambulata (Louis & Menon, 2009) and A. irregulata (Liu, 1992) are introduced. Most of the species recorded are widespread in the Indo-Pacific, and some are apparently globally distributed in the tropics and subtropics, including the invasive fouling species Bugula neritina, Hippoporina indica and Schizoporella japonica, as well as the coral reef associates Cranosina coronata and Hippopodina feegeensis. Plastic debris and glass bottles were encrusted by Jellyella eburnea, a coloniser of floating biological and man-made objects that is becoming widespread in the tropics and subtropics of the world’s oceans

Evidence of geographical structuring in the Malaysian Snakehead, Channa striata based on partial segment of the CO1 gene

Channa striata, locally known as “haruan”, is economically important in fisheries and aquaculture industries in several Asian countries. DNA sequencing, based on a partial segment of the Cytochrome oxidase c subunit 1 (CO1) gene, was used to determine genetic variation in C. striata samples from four different populations on the west coast of Peninsular Malaysia. The highest nucleotide and haplotype diversities were observed in the Linggi population (π = 0.0067, h = 0.835), and the lowest in the Timah Tasoh population (π = 0.0008, h = 0.286). Apart from Kajang-Linggi, which was insignificant, FST values were significant (p < 0.05) in all pairwise-population comparisons. Consequently, it is inferred that genetic structuring C. striata populations in this region was largely shaped by a common origin, with secondary influences from geographical factors and isolation

First record of jellyfish Anomalorhiza shawi Light, 1921 (Cnidaria: Scyphozoa) and its associated organisms in Sabah, Malaysia

The present study describes a first record of the jellyfish Anomalorhiza shawi Light, 1921 from Malaysia. It belongs to the family Lychnorhizidae Haeckel, 1880, order Rhizostomeae Cuvier, 1799 (Cnidaria: Scyphozoa). The specimen was taken from Sepanggar Bay, Kota Kinabalu, off the Universiti Malaysia Sabah (UMS) Jetty by manual collection with a bucket. The size of the bell was 430 mm in diameter with oral arms measuring 290 mm in length including the brown terminal clubs, which differentiates A. shawi from other congeners of the family. Anomalorhiza shawi belongs to the monotypic genus Anomalorhiza, and was first reported from the Philippines, with later reports from Hawaii and Thailand. In addition, A. shawi was found associated with other organisms such as the silver shad, Alepes vari (Cuvier, 1833) (Carangidae), and the crab Charybdis feriata (Linnaeus, 1758) (Portunidae). The association between jellyfish and other organisms have been discussed here. A checklist is provided for the current species of scyphozoan jellyfish reported from Malaysia

The Influence of Tidal on Water Quality in Sungai Semerak, Kelantan

A study has been done in Sungai Semerak, Pasir Puteh, Kelantan to understand the influence of tidal on river water quality. This study was carried out from June 2022 until March 2023. The main purpose for studying this river is because Sungai Semerak was one of the cleanest downstream rivers in Kelantan and faced various threats along the river. In-situ analyses were performed using YSI Multiparameter and Ex-situ laboratory analysis for total suspended solids, biochemical oxygen demand, chemical oxygen demand and ammoniacal nitrogen using HACH methods. This study shows that the Water Quality Index (WQI) for Sungai Semerak was classified as Class IV. Comparing WQI during spring and neap tide, the WQI is also in Class IV. From the result obtained from this study, tidal influenced the water quality during spring tide as the reading was higher compared to neap tide. Other factors that influence the water quality may come from human activities in Sungai Semerak, such as fish farming, runoff from the agricultural site, riverside constructions, supply bases and other factors. Further actions need to be taken, and further research needs to be conducted to assess this location to support the sustainability of Sungai

Gut Content Analysis and Selective Feeding Behavior of the Asiatic Hard Clam Meretrix meretrix (Linnaeus, 1758) in Marudu Bay

This study investigated the feeding behavior of the Asiatic hard clam, Meretrix meretrix, an important species in the artisanal fishery and commonly found in Sabah's coastal waters. The study aimed to identify the clam's primary diet and the environmental parameters that influence its feeding selection in its natural habitat. Sampling was monthly conducted for ten months, during which clam samples, environmental parameters, water samples, phytoplankton, and zooplankton were collected. Gut content analysis of 250 clams revealed that phytoplankton and zooplankton were the main food sources, representing 80.9% and 19.1% of the total food particles, respectively. Diatoms were the most common food particles ingested by the clams, while dinoflagellates only contributed a minor proportion of the total phytoplankton. The results of the dendrogram similarity analysis indicated significant differences in phytoplankton composition between gut and water samples. The one-way ANOSIM analysis indicated significant differences for all months, with an overall average R of 0.717 and P<0.001. Furthermore, the PERMANOVA following DistLM revealed that phytoplankton cell density, phytoplankton diversity, chlorophyll-a, and salinity significantly influenced the clam's particle selection process (P<0.05). In conclusion, this study offers a comprehensive understanding of feeding behavior and the dietary preference that can be utilized for the conservation of fishing grounds and enhancement of aquaculture production of the clam

Distribution of polycyclic aromatic hydrocarbons (PAHs) in sediment from Muar river and Pulau Merambong, Peninsular Malaysia

Previous studies indicated that with increasing industrialization and urbanization, pollution problems have become more significant in Malaysia. West coast of Malaysia is more populated and urbanized than the east and therefore more susceptible to various pollutants. Surface sediment samples were collected from Pulau Merambong and Muar river, Peninsular Malaysia during May 2013 where 16 USEPA Priority Pollutants PAHs were analyzed using gas chromatography-mass spectrometry. Total PAHs in the sediments for Muar river ranged from 15.5 to 165.7 ng/g dw whereas the total PAHs for Pulau Merambong ranged from 38.6 to 122.8 ng/g dw. Due to rapid urbanization and motorization, Muar river showed an increasing trend of PAHs concentrations when compared to a study conducted about a decade ago. Pulau Merambong shows relatively lower PAHs concentrations as compared to other locations in Peninsular Malaysia. However, there is no previous data in Pulau Merambong to evaluate the trend in the petroleum hydrocarbons distribution and concentrations. In general, this study revealed that the lowest concentrations were detected in downstream of the Muar and Pulau Meranbong, respectively. This study also found abundance of high molecular weight (HMW) PAHs as compared to low molecular weight (LMW) PAHs suggesting predominance of pyrogenic PAH sources via atmospheric and long-range input. The ratio of LMW PAHs to HMW PAHs (LMW/HMW) were in the range of 0.05–0.33 indicating pyrogenic input and this is consistent with other diagnostic ratios

Source type evaluation of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Muar River and Pulau Merambong, Peninsular Malaysia

This article is the most recent report of polycyclic aromatic hydrocarbons (PAHs) in the Muar River and Pulau Merambong, Peninsular Malaysia. A total of 16 priority pollutant PAHs in addition to methylphenanthrene among alkylated PAHs were analyzed in surface sediments during May 2013. Total PAHs ranged from 212 to 440 and 151 to 412 ng g−1 dw in sediments from the Muar River and the Pulau Merambong, respectively. The Muar River showed an increasing trend of PAH concentrations, while no previous data exist for the Pulau Merambong. Generally, mixed petrogenic and pyrogenic sources of PAHs with predominance of the latter were detected in the study area. Effective management of oil pollution has caused a drastic decrease in petrogenic sources of PAHs