In order to determine the safety level of water parameters and nutrients in the natural environment of fish and freshwater prawn in Nyatuh River, Terengganu, Malaysia, it is necessary to conduct an assessment of water quality parameters. Due to its important, a study was conducted to assess the water quality parameter and nutrients contents from Nyatuh River of Setiu Terengganu in relations to the population of freshwater prawn, Macrobrachium rosenbergii caught along the Nyatuh River basin. Total of four expeditions and five stations at different tidal condition for the water quality parameter were assessed during the study. From the results achieved, the overall temperature varied between (26.56°C-29.30°C), dissolved oxygen, DO (3.59 mg/L-6.50 mg/L), pH (4.99-7.01), salinity (0.01ppt-4.22ppt), depth (2.71 m-5.54 m) while for ammonia (0.01 mg/L-0.24 mg/L), nitrite (0.01 mg/L-0.05 mg/L) and phosphate (0.01 mg/L-0.12 mg/L). While the number of prawns caught are 176, 160, 102 and 68 for Expeditions 1, 2, 4 and 3, respectively. Possibly, the heterogeneous number of prawns caught is a result of significant differences in water level depth during high tides and low tides, as well as a fluctuation in the ammonia concentration levels in each of the stations and expeditions. For statistical analysis, the temperature showed no significant difference between the expedition, stations and tidal. That is p = 0.280, p > 0.05 and F = 1.206, respectively. While dissolved oxygen, DO, showed no significant difference as well, that is p = 0.714, p > 0.05 and F = 0.737. However, the level of water depth was significantly different between expedition, station and tidal, that is p = 0.000, p < 0.05 and F = 3.120. Ammonia, on the other hand shows no significant difference between expedition, station and tidal, that is p = 0.476, p > 0.05 and F = 0.973. The same goes for nitrite and phosphate concentration. There was no significant difference between expedition, stations and tidal, that is p = 0.569, p > 0.05 and F = 0.879 and p = 0.247, p > 0.05, F = 1.255, respectively. In Expedition 1, the good water quality parameter and very low ammonia concentration resulted in a larger prawn population as compared to other expeditions. The distribution or mixture of prawns caught is heterogeneous at different stations due to the significant differences in water depth and also to the fluctuation in water quality due to varying ammonia levels. In conclusion, the water quality in Nyatuh River fluctuated across expeditions, stations, and tides, as well as significant differences in water level depths between high and low tides. Due to the rapid growth and importance of industrial and aquaculture operations along the river, extra attention should be devoted to avoid the impact of excessive pollutant in order to protect the ecosystem.
Microplastics pollution has become a threat to aquaculture practices, as nearly all farming systems are saturated with microplastics (MPs) particles. Current research on MPs is limited considering their effects on aquatic organisms and human health. However, limited research has been conducted on potential cures and treatments. In today's world, bioremediation of needful parameters in different culture systems is being successfully practiced by introducing floc-forming bacteria. Researchers had found that some bacteria are efficacious in degrading microplastics particles including polyethylene (PE), polystyrene (PS), and polypropylene (PP). In addition, some bacteria that can form floc, are being used in fish and shellfish culture systems to treat toxic pollutants as the heterotrophic bacteria use organic compounds to grow and are effective in degrading microplastics and minimizing toxic nitrogen loads in aquaculture systems. In this review, the ability of biofloc bacteria to degrade microplastics has been summarized by collating the results of previous studies. The concept of this review may represent the efficacy of biofloc technology as an implicit tool in the fish culture system restricting the MPs contamination in water resources to safeguard ecological as well as human health.
Microplastics (MPs) occurrence in farmed aquatic organisms has already been the prime priority of researchers due to the food security concerns for human consumption. A number of commercially important aquaculture systems have already been investigated for MPs pollution but the mud crab (Scylla sp.) aquaculture system has not been investigated yet even though it is a highly demanded commercial species globally. This study reported the MPs pollution in the mud crab (Scylla sp.) aquaculture system for the first time. Three different stations of the selected aquafarm were sampled for water and sediment samples and MPs particles in the samples were isolated by the gravimetric analysis (0.9% w/v NaCl solution). MP abundance was visualized under a microscope along with their size, shape, and color. A subset of the isolated MPs was analyzed by scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) for the surface and chemical characterization respectively. The average MPs concentration was 47.5 ± 11.875 particles/g in sediment and 127.92 ± 14.99 particles/100 L in the water sample. Fibrous-shaped (72.17%) and transparent-colored (59.37%) MPs were dominant in all the collected samples. However, smaller MPs (>0.05-0.5 mm) were more common in the water samples (47.69%) and the larger (>1-5 mm) MPs were in the sediment samples (47.83%). SEM analysis found cracks and roughness on the surface of the MPs and nylon, polyethylene, polypropylene, and polystyrene MPs were identified by FTIR analysis. PLI value showed hazard level I in water and level II in sediment. The existence of deleterious MPs particles in the mud crab aquaculture system was well evident. The other commercial mud crab aquafarms must therefore be thoroughly investigated in order to include farmed mud crabs as an environmentally vulnerable food security concern.
The ubiquitous proximity of the commonly used microplastic (MP) particles particularly polyethylene (PE), polypropylene (PP), and polystyrene (PS) poses a serious threat to the environment and human health globally. Biological treatment as an environment-friendly approach to counter MP pollution has recent interest when the bio-agent has beneficial functions in their ecosystem. This study aimed to utilize beneficial floc-forming bacteria Bacillus cereus SHBF2 isolated from an aquaculture farm in reducing the MP particles (PE, PP, and PS) from their environment. The bacteria were inoculated for 60 days in a medium containing MP particle as a sole carbon source. On different days of incubation (DOI), the bacterial growth analysis was monitored and the MP particles were harvested to examine their weight loss, surface changes, and alterations in chemical properties. After 60 DOI, the highest weight loss was recorded for PE, 6.87 ± 0.92%, which was further evaluated to daily reduction rate (k), 0.00118 day-1, and half-life (t1/2), 605.08 ± 138.52 days. The OD value (1.74 ± 0.008 Abs.) indicated the higher efficiency of bacteria for PP utilization, and so for the colony formation per define volume (1.04 × 1011 CFU/mL). Biofilm formation, erosions, cracks, and fragments were evident during the observation of the tested MPs using the scanning electron microscope (SEM). The formation of carbonyl and alcohol group due to the oxidation and hydrolysis by SHBF2 strain were confirmed using the Fourier transform infrared spectroscopic (FTIR) analysis. Additionally, the alterations of pH and CO2 evolution from each of the MP type ensures the bacterial activity and mineralization of the MP particles. The findings of this study have confirmed and indicated a higher degree of biodegradation for all of the selected MP particles. B. cereus SHBF2, the floc-forming bacteria used in aquaculture, has demonstrated a great potential for use as an efficient MP-degrading bacterium in the biofloc farming system in the near future to guarantee a sustainable green aquaculture production.