Aquaculture Journal

Aquaculture is an important source of food, employment and economic development, but maintaining appropriate water quality remains a major challenge for farmers. Parameters like temperature, pH, dissolved oxygen (DO), turbidity and salinity have significant effects on the growth, health, feeding efficiency and survival of aquatic organisms. Traditional monitoring relies mainly on manual sampling and periodic measurements, which is time-consuming and may not provide sufficient spatial and temporal information for precision aquaculture. This paper proposes an IoT-based mobile water-quality monitoring architecture with an unmanned aerial vehicle UAV (drone) integrated with an autonomous autopilot system. The system receives the registered GPS coordinates of an aquaculture pond and automatically navigates the UAV to the pond for measurement. When the UAV arrives at the pond, it visits several preselected sites and submerges a detachable multi-parameter sensing module to collect the water-quality parameters. An embedded controller processes the sensor data and transmits the measurements, GPS coordinates and time stamps to a cloud database via wireless communication. One mobile sensing unit can monitor multiple ponds and form a spatially indexed historical database of water quality. The architecture lays a foundation for AI-based anomaly detection, water-quality prediction, disease-risk assessment, and intelligent decision support for precision aquaculture.

Expanded polystyrene floats have been identified as a significant source of marine microplastic in oyster aquaculture, yet no certification criterion assesses the material that the certified alternatives shed. Gravimetric mass loss, normalised to a common exposed area of 7200 mm², is reported under accredited accelerated weathering to KS F 2274 for eight float materials: expanded polystyrene at three densities, expanded polypropylene, three injection-moulded polymers, and a continuous-fibre basalt-reinforced thermoplastic composite. Specimens were dried to constant mass before weighing, so the quantity measured is a net change: an upper bound on particulate release, not a measure of it. Mass exceeded the initial value in all three stabilised expanded polypropylene specimens. At 3000 h the loss spanned a factor of 54, and every foamed material exceeded every non-foamed one, while tripling the density of expanded polystyrene reduced loss by only 25% (n = 3; p < 0.0001 across the foamed groups). For ten injection-moulded grades the accelerated ranking reproduced that of 2.5 years outdoors (Spearman ρ = 0.89), though the ratio varied from 0.4 to 6.3. A wear model indicates that the pure-polymer barrier providing water tightness contains 905–1180 g L⁻¹ of polymer against 578 g L⁻¹ for the laminate beneath, so the wearing layer, not the bulk material, may govern release in service.

The Chilean silverside (Basilichthys microlepidotus) is an endemic freshwater species considered Vulnerable, and the species-specific bioengineering parameters needed to design efficient recirculating aquaculture systems (RAS) for this species, particularly oxygen consumption, remain unknown. A factorial experiment (2 × 2) was conducted to evaluate how body size and stocking density affect the routine oxygen consumption of B. microlepidotus. The study considered two body-size groups and two stocking-density treatments, each represented by three replicate tanks. Oxygen uptake rates were determined from mass-balance calculations in a static closed respirometry system during sequential 24 h periods. Body size significantly influenced mass-specific oxygen consumption, with smaller fish exhibiting higher rates than larger fish, consistent with allometric metabolic scaling, whereas no significant independent effect of stocking density was detected; however, with only three tanks per treatment and two similar densities, the test had low power and this result is inconclusive. A pronounced diurnal pattern was evident in all treatments, with the main oxygen consumption peak near 14:00 h, approximately three hours after the single daily feeding (11:00 h), which is consistent with, but does not demonstrate, a specific dynamic action (SDA) response because no unfed control was included; a smaller peak near 08:00 h preceded feeding and may reflect routine laboratory activity at the start of the working day. These results provide the first species-specific reference values of routine oxygen consumption for B. microlepidotus, offering a preliminary basis, within the size and density ranges tested, for estimating the oxygen demand of fish in RAS designed for this species, with direct relevance for both conservation-oriented restocking and its development as a candidate for freshwater aquaculture diversification.