Marine plastic debris, particularly microplastics (MPs), is an urgent and significant threat to the global marine environment. The emergence of MPs in the marine environment and their potential presence in human-consumed seafood necessitates immediate investigation. In light of this, a study was conducted on the occurrence of MPs in shellfish collected from two locations in Makassar Strait with distinct oceanographic conditions. Three commonly consumed shellfish species (Perna viridis, Meretrix meretrix, and Mactra chinensis) were collected by fishermen and examined for microplastic contamination, with a total sample size of 170 individuals. Microplastics were extracted from the soft tissue of the bivalves using the alkaline digestion method. The results revealed a significantly higher number of microplastics ingested by P. viridis and M. chinensis in samples collected from the Sanrobengi Islands (14.64 MPs/individual and 2.29 MPs/individual, respectively), compared to the P. viridis and M. meretrix from Mandalle coastal area (0.70 MPs/individual and 1.00 MPs/individual, respectively). The predominant microplastic form detected was blue microfibres. A prevalence of MP contamination between 58 and 100% and the results of Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated that polystyrene was the dominant polymer present, threatening the welfare of the bivalve mollusks and posing potential health risks to seafood consumers. The results emphasize the urgent need for pollution control measures such as reducing plastic waste discharges and improving waste management systems. In addition, a comprehensive study focusing on the long-term ecological and health effects of microplastic pollution is necessary to guide future policy interventions.

With the increasing global population, ensuring food security has become one of the major global challenges, particularly in relation to protein food sources. Aquaculture activities are generally considered a potential alternative for providing protein-rich food. However, conventional aquaculture production systems require substantial water usage, which is often scarce in certain areas. Recirculating aquaculture systems (RAS) have emerged as a water-efficient method of aquaculture production. However, literature on diurnal trends of water quality within RAS is still limited, making it challenging to establish standard operating procedures (SOPs) for water quality monitoring in RAS. This study aimed to examine the diurnal patterns of several water quality parameters in a semi-outdoor RAS used for the cultivation of the red tilapia (Oreochromis sp.). Water quality parameters were measured every three hours over a 24-hour period. The results showed distinct diurnal trends for each observed parameter, including total ammonia nitrogen (TAN), un-ionized ammonia (NH3), dissolved oxygen, oxygen deficit, pH, and temperature. TAN, dissolved oxygen, and pH exhibited higher values in the morning (6:00–9:00). In contrast, temperature and oxygen deficit were generally higher in the evening (18.00–21.00). Based on these trends, the best times for water quality monitoring in semi-outdoor RAS are predicted to be at 09.00 and 18.00. Further research is needed, especially in locations with different climates and altitudes, to validate and expand these findings.