Since the 1970s, artificial reef (AR) deployment has been one of the common approaches to augment the local production of coastal fish in Malaysia. However, there is a lack of strategy to assess and evaluate the success of pre-deployed AR. Realizing the need for an effective qualitative and quantitative monitoring and evaluation of AR, this study proposes side-scan sonar coupled with scuba diving observation for the enhanced monitoring of pre-deployed Bioceramic Korean (BK) AR along the coast of Terengganu, Peninsular Malaysia. This method employs an integrated side-scan sonar with a data acquisition system for the detection of the precise location of the BK AR which were deployed at Tukun Telaga Batin off the Terengganu coastline in 2003 by the Fisheries Development Authority of Malaysia (FDAM). Following the determination of the exact location of three BK AR areas, a scuba diving team was sent to survey the physical conditions of the AR and assess the feasibility of the AR as an artificial habitat for marine life. The scan sonar images were compared with the captured photographs and videos acquired during the scuba diving session for a comprehensive value-added assessment. The collected data from the scuba diving session were also processed to measure the fish diversity, the fish biomass, and identify the fish community surrounding the AR. Based on the results, the BK AR remained in extremely good condition, physically intact, without significant breakage or damage, and with no major subsidence into the sediment after 19 years of deployment. A total of 108 BK AR modules were detected in three large groups using the mosaicked sonar images. Following cross-examination to validate the AR measurements using the AR’s shadows on the seafloor, the height of the BK AR consistently ranged from 1.7 m to 1.8 m. In addition, 34 species of fish from 14 families and 26 genera were identified, with most species classified as reef-associated (RA) fish with a biomass value of 1173.31 ± 1136.69 kg m⁻³, indicating the successfulness of the BK AR as fish-aggregating devices (FADs). The growth of hard corals on top of the bioceramic plate of the AR module further supported the diversified community of marine life surrounding the BK AR. In conclusion, the side-scan sonar coupled with scuba diving observation demonstrates an effective qualitative and quantitative technique for the monitoring and evaluation of pre-deployed AR. This strategy is recommended to be utilized to determine the success of pre-deployment AR.

Hydrocarbon compounds viz. aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), sterols, long chain fatty acids, alkanones and alkanals in surface sediment of Setiu Wetland were analysed and characterized using GCMS. The concentration of total identified resolved n-alkanes (TIRNA) in sediment ranged from 2.99–11.6 μ g g^{− 1} dry weight. The distribution of the aliphatic fraction showed the presence of n-alkanes ranging from C ₁₂ to C ₃₆ with high predominance for long chain homologues (C ₂₅ -C ₃₁ ) and a carbon maximum at C ₂₉ and C ₃₁ with CPI > 3; these observations provide evidence for the presence of biogenic terrigenous input corresponding to epicuticular plant waxes into the lagoon sediments. Positive and strong correlation between n-alkanes associated with terrigenous input (ALK TER) and TIRNA suggest terrestrial input is the main sources of TIRNA in this study area. The absence of unresolved complex mixture (UCM) in the chromatogram and the absence of hopanes, steranes and PAHs compounds are indicative of uncontaminated sediment by petrogenic and pyrogenic hydrocarbons. The concentration of total identified sterols (TIS) ranged from 1.41 μ g g^{− 1} dry weight to 3.11 μ g g^{− 1} dry weight with cholesterol, β -Sitosterol and stigmasterol were generally the most dominant and abundant components detected at almost all stations. A positive and strong correlation was observed between B-Sitosterol and TIS and the distribution of long chain n-alkan-2-ones in the range of C ₂₁ to C ₂₇ with odd to even predominance and n-alkanals (C ₂₀ to C ₂₈ ), n-alkanols (C ₂₂ –C ₃₀ ) and n-alkanoic acids (C ₂₂ –C ₃₀ ) with even to odd predominance provide further evidence for biogenic sources of hydrocarbons with terrestrial plant input as the predominant source. It was noted that a minor contribution associated with marine phytoplankton (algae) as well as bacteria were also observed in some of the sediment samples superimposing with the terrigenous plant wax input. In general results from this study clearly showed the lagoon sediment of Setiu Wetland is still in uncontaminated condition where terrestrial plants input are the dominant contributor of organic compounds in the sediments with a minor input from marine organisms.

The purpose of this study was to characterize and determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) emitted in smoke particulates from burning of Rhizophora apiculata, Melaleuca leucadendron and Hevea Brasilensis at the smouldering, flaming and charring stages. Smoke particulates were sampled using a total suspended particulate Hi-volume sampler (HVS) at a rate of 1.13 m3/min and PAHs were extracted with a mixture of dichloromethane-methanol (3:1 v/v) using ultrasonic agitation. Fractionation of PAHs was carried out on an alumina-silica column and analysis by gas chromatography-mass spectrometry (GC-MS). The results showed that most of the samples exhibited the highest total identified PAHs in the smouldering stage with formation of PAHs with three rings or more increasing from the smouldering to flaming stages and reducing as combustion entered the charring stage. Naphthalene, phenanthrene and pyrene were the dominant PAHs detected in the wood smoke particulates, depending on combustion stage. Overall the emission and formation of PAHs are strongly dependent on combustion stage as well as other factors such as wood morphology, species, moisture content and combustion temperature.