Aquaculture, Aquarium,
Conservation & Legislation

Constructed wetlands (CWs) are increasingly recognized as sustainable systems for the treatment of aquaculture wastewater, where nutrient removal is governed by complex interactions among plants, microbial communities, and substrate processes. This review critically evaluates the potential role of selected textile and industrial crops - Chrysopogon zizanioides (vetiver), Phalaris arundinacea (reed canary grass), Cannabis sativa (hemp), and Hibiscus cannabinus (kenaf) - within CWs designed for aquaculture effluent remediation. The analysis highlights that nutrient removal is predominantly microbially mediated, while plant contributions are largely indirect, influencing rhizosphere conditions, oxygen transfer, and biomass harvesting dynamics. Among the evaluated species, vetiver demonstrates the strongest evidence for direct application in aquaculture wastewater, including tolerance to mesohaline conditions and effective nitrogen and phosphorus removal. Reed canary grass shows robust performance in CW systems, particularly when biomass management strategies are optimized, although aquaculture-specific data remain limited. Hemp is primarily supported as a biochar-derived substrate for phosphorus adsorption rather than as a planted macrophyte, while kenaf lacks direct evidence in CW contexts, representing a significant research gap. The review further emphasizes the importance of hydraulic loading rates, salinity tolerance, and plant–microbe interactions in determining system performance. Future research should prioritize long-term, field-scale studies and a mechanistic understanding of trait-mediated plant effects to optimize the integration of industrial crops into aquaculture wastewater treatment systems.

Vibrio alginolyticus is an important bacterial pathogen causing hemorrhagic disease and significant mortality in marine fish, including red drum, Sciaenops ocellatus (Linnaeus, 1766). This study evaluated the efficacy of an enteric-coated oral inactivated V. alginolyticus vaccine and optimized vaccination strategies to improve protection against vibriosis. A virulent strain (VA15) was selected for challenge experiments, with a median lethal dose (LD₅₀) of 2 × 10⁴ CFU fish-1. Juvenile red drum (14-16 g) were orally immunized with vaccine doses ranging from 10⁵ to 10⁷ CFU equivalent fish-1 to determine the optimal antigen concentration. Antibody titres increased significantly following vaccination and reached peak levels at 21 days post-immunization. As no significant difference was detected between the 10⁶ and 10⁷ CFU equivalent fish-1 groups, the 10⁶ CFU equivalent fish⁻¹ dose was selected for subsequent trials because it provided comparable immunogenicity while requiring less antigen. The protective efficacy of unencapsulated and enteric-coated vaccine formulations was subsequently evaluated using different booster schedules. Fish receiving the unencapsulated vaccine achieved a relative percent survival (RPS) of 44%, whereas enteric coating increased RPS to 54% following a single vaccination. Booster immunization further enhanced protection, with RPS values increasing to 61% and 78% when boosters were administered on days 14 and 21, respectively. These findings demonstrate that enteric coating improves oral vaccine delivery and that a booster vaccination administered 21 days after primary immunization provides the highest level of protection against V. alginolyticus infection. Although the study was conducted under laboratory conditions using a single bacterial strain, the results highlight the potential of enteric-coated oral vaccines as a practical disease management strategy for marine aquaculture.

The use of contaminated brine shrimp, Artemia franciscana (Kellog, 1906), as live feed leads to vibriosis outbreaks and threats to global aquaculture productivity. This study highlights a potential cost-effective and environmentally friendly approach to suppress Vibrio spp. load in Artemia live feed. Axenic A. franciscana nauplii were reared with Vibrio campbellii and Vibrio parahaemolyticus under 30-150 PSU of salinity. A salinity of 80 PSU can eliminate more than 90% of both strains, while maintaining over 90% survival of A. franciscana nauplii. Another experiment demonstrated that the Vibrio spp. load in non-axenic cyst-hatching tanks at 30 PSU was high but reduced with increasing salinities. The addition of 1 g L-1 Pandanus tectorius leaf extract in the high salinity rearing water significantly reduced cyst-derived bacterial load. Findings showed that 80-110 PSU of salinity is effective in suppressing almost all the Vibrio spp. without adverse effects on A. franciscana growth, removing the need for cyst disinfection or nauplii tank transfer.