Seafood, especially from the ocean, is now seen as a greener and more sustainable source of protein, causing an increase in its demand. This has also led to people making choices towards seafood as a replacement for carbon-intensive protein sources. As a result, the demand for seafood is growing, and as the aquaculture industry looks to increase production, keeping products safe and sustainable is imperative. There are many challenges faced by the aquaculture industry in meeting these increased demands. One such challenge is the presence of harmful algal blooms (HABs) in the ocean, which can have a major impact on aquatic life. In this paper, we look at the impact of this challenge on aquaculture and monitoring strategies whilst illustrating the potential for technological interventions to help mitigate the impact of an HAB. We will focus on Abagold Limited, a land-based marine aquaculture business that specialises in the large-scale production of abalone (Haliotis midae) based in Hermanus, South Africa. HABs are considered a threat to commercial-scale abalone farming along the South African coastline and require continuous monitoring. The most recent HAB was in February–April 2019, when the area experienced a severe red-tide event with blooms of predominantly Lingulodinium polyedrum. We present some of the monitoring strategies employing digital technologies to future-proof the industry. This article presents the development of a novel hybrid water quality forecasting model based on a TriLux multi-parameter sensor to monitor key water quality parameters. The actual experimental real water quality data from Abagold Limited show a good correlation as a basis for a forecasting model which would be a useful tool for the management of HABs in the aquaculture industry.

In recirculating aquaculture systems (RAS), understanding the relationship between feed load and its impact on water quality and overall shrimp health is important. This study utilised an indoor marine RAS for the intensive culture of Pacific white shrimp Litopenaeus vannamei. The shrimp were stocked into the grow‐out system at an average body weight of 0.25 g and a stocking density of 347 shrimp/m³. Water quality parameters of temperature, salinity, total dissolved solids, pH, and dissolved oxygen (DO) were measured twice daily. Total ammonia nitrogen (TAN), nitrite and nitrate were measured once weekly or when needed. Sampling was conducted to calculate the daily feed ratio based on the total estimated biomass. Mortality was recorded as a means of evaluating the overall shrimp health. The data obtained were analysed using Pearson correlation (r) analysis and multi‐linear regression with a significant difference accepted p < 0.05. Correlation (r) established relationships among the water quality parameters, feed load and mortality. The TAN level of 24.20 mg/L was recorded when the feed load increased by 81.2% resulting in the mortality of 40% of shrimp. A negative correlation between TAN and DO resulted in a synergistic effect causing a massive consumption of DO in the water, reducing its availability to the shrimp and leading to a drastic change in the shrimp's behaviour. Overfeeding can lead to an accumulation of uneaten feed and waste, causing ammonia spikes and oxygen depletion in the water. Monitoring and adjusting feed rates accordingly can help maintain optimal water conditions for shrimp growth and health. Therefore, it is essential to use appropriate feed rates in recirculating systems because feed load can influence water quality parameters that can be detrimental to shrimp culture.

We report an analysis of data from Nb/AlOx/Nb tunnel junctions. We show that both conductance and subgap leakage follow simple scaling laws as a function of oxidation conditions. The leakage effects are discussed in terms of a simple physical model of tunnel barrier inhomogeneity that is also applicable to directly deposited barriers on NbN. We demonstrate that an improvement in barrier properties can be achieved by the use of a buffer layer overlying the barrier, and that this improvement is consistent with a model based on resputtering effects.

Seafood, especially from the ocean, is now seen as a greener and more sustainable source of protein causing an increase in its demand. This has also led to people making choices towards seafood as a replacement of carbon intensive protein sources. As a result, the demand for seafood is growing, and the Aquaculture industry is required to increase their produce while keeping the produce safe and sustainable. There are many challenges faced by the aquaculture industry in meeting these increased demands. One such challenge is the presence of harmful algal blooms (HAB) in the ocean which can have a major impact on aquatic life. In this paper we look at the impact of this challenge on aquaculture and the mitigating strategies. We will focus on Abagold Limited, a land-based marine aquaculture business that specializes in large scale production of abalone (Haliotis midae) based in Hermanus, South Africa. HABs are considered a threat to commercial scale abalone farming along the South-African coastline and requires continuous monitoring. The most recent HAB was in February-April 2019, the area experienced a severe red-tide event with blooms of predominantly Lingulodinium polyedrum. We present some of the mitigation strategies employing digital technologies for future proofing the industry.