Reef rubble representsthe broken components of the coraland reefstructure which could be in the form of dead,broken or other fragmented coral.The process to estimate the distribution of reef rubble is currently done manually and thus takesa long timeto completeand is laborious. This paper presentsan image-processing-basedmethod to estimate the distribution of reef rubbles in a coral reef environmentfrom a still image. The method is basically a series of image processing steps includingimage complement, image binarization, edgedetection, smoothing by Weiner filter and followed by erosion and dilation process.The experimentalresults showedthat the system wasable to roughly estimate the distribution of reef rubble.
At present, marine scientists employ manual method to estimate the components in coral reef environment,where Coral Point Count with Excel extensions (CPCe) software is used to determine the coral reef components and substrate coverage. This manual processis laboriousand time consuming,and needsexpertsto conduct the survey. In this paper, a prototype for estimating the distribution of sand cover in coral reef environment from still images by using colourextraction methods was introduced. The coloursegmentation called delta E was used to calculate the colourdifference between two coloursamples. Another method used wascolourthresholdby setting the range of sand colourpixels. Thesystem was developed by using a MATLAB software withimage processing toolbox. The developed system was semi-automatic computer-based system that can be used by researcherseven with little knowledge and experience to estimatethepercentage of sand coveragein coral reef still images.
Degradation of coastal water quality is one of the major concern in the Malacca Strait since this area is one of the most important fishing ground in Malaysia. Despite being great in the fishery industry, Malacca and Negeri Sembilan somehow recorded the lowest marine fishes landing, which raises a question about dynamics of this area. It is therefore, a preliminary study of the physical properties and nutrient concentrations carried out from 27 March to 4 April 2016 at the coastal water off the southern west coast of Peninsular Malaysia, specifically at Pulau Besar, Malacca and Tanjung Tuan, Negeri Sembilan. Data for temperature, salinity, and dissolved oxygen (DO) was acquired by using Conductivity, Temperature, and Depth (CTD) probe. Meanwhile, nutrient concentrations determination in this study was done by using a Westco Smartchem 200 Discrete Analyser, according to the procedure adopted from United States Environmental Protection Agency (USEPA). In general, results of this study indicated the coastal stations were characterised with cooler, less saline, and high DO waters than stations away from coast. Large sea surface heating and weak winds were determined as the causative factors affecting dynamics of water column at the study area. At nearshore area, temperature, salinity, and DO variability were modulated by degree of freshwater intrusion. High nutrient concentrations at the stations closer to the coast was believed to be associated with river outflow, which acted as the main source of nutrients supply in this area. Comparison to previous study had shown that nutrient concentrations in this research were low, which could contribute to an insight on declining marine fish catches in these two states. With regard to Malaysian Marine Water Quality Criteria and Standard (MWQCS), mean nutrient concentrations at the study area were in Class 1, which are suitable for marine parks and marine protected areas conservation. Regardless of limited scope, the outcome of this study is believed to be a good baseline reference for future studies seeking to understand coastal dynamics.