Biology of Incidental Catch Sea Star Stellaster childreni

Sea star (class Asteroidea, phylum Echinodermata) is one of the most successful marine organisms inhabiting a wide range of habitats. As one of the key stone species, sea stars are responsible for maintaining much of the local diversity of species within certain communities. Malaysian Exclusive Economic Zone (EEZ) Resource Survey had been carried out from 16th Aug to 6th Nov 2015 and one of the invertebrate by-catch organisms is sea star Stellaster childreni Gray, 1840. This study documents morphological characters and diet of the sea star, besides providing brief descriptions of the habitats based on particle size analysis and vessel log data sheet. A total of 217 individuals had been examined throughout this study. Fragments of flora and fauna were found in the gut including Mollusca (gastropod, bivalves, and scaphopods), sponge seagrass, and seaweed as well as benthic Foraminifera. Stellaster childreni were found at depth of 45 m to 185 m in the South China Sea off Sarawak Malaysia, with various sea bottom substrata. Approximately 41% of S. childreni were found at a mixture of sandy and muddy substratum, followed by mixture of sandy and coral (19.3%), muddy substratum (17.5%), coral substratum (11.5%), and sandy areas (10.6%). The widely distributed sea star on different types of sea beds suggested healthy deep sea ecosystem; thus Malaysia should explore further potential fisheries resources in the EEZ off Sarawak coast

Checklist of sergestid shrimps, Acetes (Decapoda: Sergestidae) from selected sites along the coastal water of Sarawak, Malaysia

Acetes is exploited by the local people of Sarawak as a source of income during its bloom season, processed into local products such as fermented shrimp paste and pickle. Despite its importance in socio-economy, little is known on Acetes species composition in the coastal water of Sarawak, Malaysia. The objective of this study is to provide checklist of Acetes species found in the coastal water of Sarawak. Acetes samples were collected at three different sites namely Lundu, Telaga Air and Miri using bottom trawl net and traditional fishing gears. Four species were identified based on the morphological characters namely A. erythraeus, A. serrulatus, A. japonicus and A. indicus and A. erythraeus is the new record for Sarawak. © 2020 Malaysian Nature Society. All rights reserved

Preliminary study on cyanobacteria composition and selected water quality parameters from freshwater fish (tor tambroides) ponds in Serian, Sarawak

Toxic cyanobacteria, for example, species from the genera Microcystis,Anabaena and Oscillatoria may present risk of cyanotoxin bioaccumulation in fish tissues either directly or via other organisms in the food web, consequently posing hazard to aquatic animals and humans. A study was conducted to determine cyanobacterial species composition and their relationships with selected water quality parameters. Water samples were collected from subsurface of two Tor tambroides (locally known as empurau) aquaculture ponds in Serian District, Sarawak from January to June 2007. There were 35 cyanobacterial species recorded from 11 genera of four families. Common occurrence of Chroococcus, Nostoc, Oscillatoria, Pleurocapsa and Synechocystis genera were observed in both ponds. In Pond P12, visible brownish bloom which consists of Microcystis and Anabaena were observed. The correlation ccr-efficient analysis in Pond AP22 showed that cyanobacterial cell density has significant positive correlation with biological oxygen demand (r =0.839, p<O.01). Chlorophyll a concentration showed significant positive correlation with turbidity in both ponds (r =0.861, r<O.01 in Pond AP22 and r =0.849, p<0.01 in Pond P12). Further research should be carried out to determine the presence of cyanotoxin in those aquaculture ponds

Preliminary Investigation on Vertical Distribution of Phytoplankton Biomass and Nutrients in Tasik Biru (Blue Lake), Bau, Sarawak.

Located in Bau district, Sarawak, Tasik Biru, formed from an open cast gold mining pit, was opened to the public as recreational area in 2001. Due to the gold mining activities, the water contains high content of arsenic as declared by Natural Resources and Environmental Board (NREB) of Sarawak. Therefore, this study served as a baseline data on determining the fertility of the lake in terms of phytoplankton biomass composition. The study was carried out in seven months period (May -November 2007). Water samples were taken from three different depth namely subsurface, middle and bottom layers at the shallow side of the lake for determination of chlorophyll a concentration. Besides that, the nutrient analyses namely orthophosphate, nitrate and ammonia were also conducted to observe their relationship with phytoplankton biomass. Tasik Biru was categorized as oligotrophic lake based on the range of the chlorophyll a concentration in the sampling period (0.6831 IJ.g/t to 3.1047 IJ.g/f)

The diversity of Cyanobacteria from selected aquatic ecosystems in Sarawak

Cyanobacteria are microalgae that have the characteristics of both bacteria (prokaryotic cell organization) and algae (ability to photosynthesize like plants). They belong to the class Cyanophyceae. They have the ability to grow in most diverse ecological conditions and are very beneficial to mankind, although several produce toxins which may be toxic to human and animal. In addition, some cyanobacteria produce odorous metabolites that can cause "off-flavor" which have significant negative impact to the aquaculture sector. The aim of this study is to provide an update on the diversity ofcyanobacteria in selected Sarawak aquatic ecosystem with focus on their composition and the evaluation of their diversity using beta indices. A number of eight stations which include aquaculture ponds, cage cultures, waterfall and artificial lake located in Serian, Bau and Batang Ai area were selected for this study. The Wilson & Shmida's (1984) formula was selected to analyze the beta diversity of the identified cyanobacteria. A total of 43 species belonging to 30 genera were recorded. Oscillatoria was the best represented genus, comprising 9% of the species composition in the samples. The most distributed pattern among all the sampling sites was of the genera Chroococcus, Lyngbya, Noctoc and Oscillatoria. The highest 8 diversity value was found among non-contiguous sites. There were no identical or totally different c'yanobacteria diversity values among those noh-contiguous sites. The highest 8 diversity values were found among sites with contrasting environmental characteristics. The wide rari~e of 8 diversity suggested that variations in the physico-chemical properties of the water may exist among the different locations and types of aquatic ecosystems which lead to the difference in cyanobacteria composition

Green Sea Turtle (Chelonia mydas): a Historical Review With Relevance to Population Size in Sarawak

Green sea turtles (Chelonia mydas) are using selected Sarawak sandy beaches for nesting. Its small-scale conservation efforts have started since the 1950s. However, the success of the effort is still debatable. Moreover, public participation in the conservation effort is still at an infancy stage. This study involved analysing nesting data of green turtles of Sarawak Turtle Islands (STIs) in terms of numbers of turtle landing, eggs collected, eggs incubated, and eggs hatched for Sarawak’s green turtle population from 1949 to 2016 with addition of estimation of the egg-laying females and their remigration interval. There was a sharp decline in terms of number of turtle landings from 1949 to the 1970s. The exact cause of this pattern could only be confirmed from old articles of historical value due to limited information on the events happening during those 30 years period. From 1980 to 2016, the annual nesting trend of turtles on STIs shows irregular fluctuation pattern and remigration interval of every 3 to 4 years with internesting frequency of 3. Turtle eggs were harvested annually, with a 36-year average of 223,558 eggs per year. Detailed analysis for data 1980 to 2016 shows that the lowest percentage of eggs incubated was in 1981 (20.4 %) and starting from the year 1991, egg incubation at STIs reached between 90 to 100 percent. There is an upward trend of egg hatching rate for the past 36 years, especially from the 1990s to 2000s, with the latest seven years average of 60%. The results imply that conservation of green turtle in Sarawak have been successful at different levels. However, there is still a need for relevant state agencies to modify and step-up efforts related to conservation of green turtles in Sarawak especially in terms of male:female ratio of hatchlings from STI’s hatcheries

Toxicity Assessment of Cyanobacterial Strains Using Brine Shrimp and Mouse Bioassay

Cyanobacterial samples were collected from aquaculture ponds in Sarawak and Sabah. Strain belonging to Microcystis sp. were isolated and maintained in laboratory cultures. Mass cultures were performed and the cells were harvested in their late exponential phase of growth. Each strain was lypholized and extracted using methanol to get the crude extract. Five different concentrations were tested in brine shrimp assay and the extracts were toxic with a LC50 of less than 50 μg/ml within 24 hrs observation. Mouse bioassay was done via intraperitoneal injection of 1.0 ml of a lysate of toxin extract into ±20 g white mice. The preliminary screening of toxin extracts using brine shrimp and mouse bioassay indicates that the strains are potentially toxin producer species and subjected to further examine using high performance liquid chromatography method

Debris Marin : punca dan penyelesaian

Buku ini mengupas isu berkaitan sampah yang bertaburan di pantai. Perbincangan yang dibuat adalah berdasarkan aktiviti dokumentasi sampah di sekitar pantai di Sarawak pada tahun 2008 dan 2010. Antara lain, ia bertujuan untuk membantu para pembaca memahami masalah di sebalik keadaan itu dan apa yang boleh dilakukan bersama untuk mengurangkan keadaan sampah yang semakin berleluasa di pantai. Diharapkan buku ini dapat meningkatkan lagi kefahaman pelbagai lapisan masyarakat Malaysia tentang isu yang begitu signifikan dalam kehidupan mereka

Population Genetics of Tor douronensis in Sarawak – A Revisit

Tor douronensis, known locally as Semah, is one of the valuable resources of Sarawak due to its high nutritional value and demand as game fish. Several molecular studies related to T. douronensis have been carried out and deposited in GenBank including the data collected from Ba Kelalan, Layar and Limbang. Although there are other studies on Tor spp., the data was not available in GenBank, thus there are not included in the analysis. One fieldtrip to Bakun Dam was carried out on June 2014 with initial aim to assess overall fish diversity. During this sampling, 11 individuals of T. douronensis were caught, which later subjected to molecular work to investigate the genetic structure and evolutionary relationship among four of T. douronensis in Sarawak using partial Cytochrome c oxidase I (COI) mtDNA gene. A fragment of 465 bp of CO1 gene of T. douronensis was successfully amplified. Based on the phylogenetic trees generated, three clades could be observed namely Central, Southern, and Northern populations; 1st clade (haplogroup I) from Bakun, 2nd clade (haplogroup II) from Layar and 3rd clade (haplogroup III) from Ba Kelalan and Ulu Limbang. Overall, there were 13 haplotypes and none was shared among populations, suggesting low level of inter-population gene flow has been observed. The small number of migrants per generation (Nm<1.0) among the population indicated that the small populations were isolated possibly due to large geographical areas. All population had undergone expansion with a large negative value and significant test of Fu’s F in Bakun population suggested recent expansion. In addition, result also suggested that all populations did not deviate from evolutionary neutrality