The amount of marine debris is increasing worldwide and has become a matter of serious concern. It is important to identify the nature of debris to understand the sources and to devise practically feasible methods for managing this problem. This study was carried out at Sebatik Island on the east coast of Sabah with the aim of examining the types and abundance of macro – and micro-debris. The observations covered a period of December 2015 – May 2016. Debris collected from different stations was compared. Transect line method was used to assess the stranded macro-marine debris (SMD). Evaluation of floating macro- debris (FMD) was done by surveys of the selected areas. Density separation technique was applied in order to extract the micro marine debris (MMD). Results showed 14 types of SMD and 9 types of FMD in the study areas. Three major types of SMD and FMD were discarded plastic, organic debris and plastic bottles. Four types of MMD recorded at the beach and mudflat areas were fragments, fiber, films and polystyrene. Based on the comparison between stations (S), S2 showed the highest abundance of SMD with 80 items m-2. Meanwhile, FMD at one location was as high as 94 items m-2. Station S3 has the highest of MMD with 22 items ml-1. Plastic formed (40%) of the SMD category whereas FMD constituted 42 % at the Sebatik Island. Small fragments and film were the most abundant of MMD (32 %). This study highlights the scale of the marine debris problem in Sebatik Island and calls for a comprehensive plan of action to protect the Island’s marine ecosystem services.
The growth performance of red claw crayfish, Cherax quadricarinatus, fed diets with different sources and concentrations of natural calcium was evaluated. Formulated diets containing 30% protein and 8% lipid were prepared using supplementation of 0 (control), 3%, 6%, 9% eggshell, and 6% seashell. C. quadricarinatus juveniles with an average total weight of 0.21 ± 0.01 g and length of 25.0 ± 0.10 mm were obtained from ten ovigerous females bred in captivity. An aquarium with a size of 0.72 m² was divided into eight compartments with an area of 0.09 m² per compartment and was individually stocked with juvenile crayfish. A total of eight juvenile crayfish were used per dietary treatment. There were five dietary treatments in total and each of these treatments were replicated three times. The addition of eggshell and seashell powder exerted positive effects on the growth performance, molting frequency, and survival of the crayfish. Crayfish fed with a 6% eggshell-supplemented diet exhibited the best overall growth performance. The calcium percentage of the carapace increased with the increase in calcium content of the diets. Meanwhile, the performance of diets comprising eggshells and seashells was not significantly different (P > 0.05). Considering the low cost and abundance of eggshells, the addition of 6% of this product to the diet is recommended for the best growth of juvenile C. quadricarinatus.