Land-based Marine Aquaculture Research Articles

Understanding Carbon Footprint in Sustainable Land-Based Marine Aquaculture: Exploring Production Techniques

In aquaculture, it is crucial to understand and mitigate the carbon footprint for sustainable production. As demand for seafood increases, various production techniques compete for an eco-friendly status. This review examines the carbon footprint of various land-based marine aquaculture systems, highlighting their environmental impact. Through exploring innovations and best practices, it navigates the complexities of reducing emissions and promoting carbon sequestration. Some proposals for this purpose are based on diversification through low-trophic-level species, the preservation of high-carbon sequestration sites, polyculture, organic aquaculture and improvements in nutrition, feeding, waste and energy management. In this sense, some land-based aquaculture systems are progressively adapting and updating their zootechnical procedures. Recirculating Aquaculture Systems (RASs) offer interesting advantages such as water conservation, pollution reduction and biosecurity. Integrated Multi-Trophic Aquaculture systems (IMTAs) aim to address two major issues in aquaculture: efficient water usage and the environmental impact of effluents, which are rich in organic particles and dissolved nutrients from undigested food and feces; hence, these systems involve cultivating multiple species (polyculture). Biofloc Technology (BFT) is based on the formation of bioflocs in a culture medium. These systems can enhance feeding efficiency and waste management, thus optimizing nutrient utilization and minimizing environmental impact, achieved through reduced water and fertilizer usage. Traditional (extensive) aquaculture systems operate with minimal input of feed and chemicals, relying heavily on the natural productivity of the ecosystems; thus, the need for manufactured feed, the environmental impact associated with feed production and the transportation and overall costs are significantly reduced. Overall, while RASs, BFT and extensive systems in general offer significant sustainability benefits, IMTA’s holistic approach to ecosystem management and nutrient recycling makes it, in our estimation, the most effective method in terms of ecological footprint in aquaculture. However, its quantitative evaluation is extremely complex, and there is currently a lack of references about its global carbon footprint. Therefore, further research and development are required, as well as collaboration and knowledge-sharing among stakeholders.

Mitigating the Impact of Harmful Algal Blooms on Aquaculture Using Technological Interventions: Case Study on a South African Farm

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.

Microbial Diversity in Groundwater and Its Response to Seawater Intrusion in Beihai City, Southern China.

Seawater intrusion is a major concern commonly found in coastal aquifers worldwide. Because of the intense aquifer exploitation and land-based marine aquaculture in the coastal area of Beihai City, Guangxi Zhuang Autonomous Region, China, numerous underground aquifers in this area have been affected by seawater intrusion. However, the microbial communities in freshwater aquifers and their response to seawater intrusion are still unclear. In this study, groundwater from three aquifers was collected from three monitoring sites at different distances from the coastline in the coastal area of Beihai City, and the hydrochemical characteristics of these groundwater samples and the structure of the associated microbial communities were analyzed. The Cl− concentration of the samples indicated that seawater intrusion had occurred in the research area up to 1.5 km away from the coastline, but the monitoring site 2 km away from the coastline had yet to be affected. Statistical analysis showed that the bacterial communities in different groundwater aquifers were significantly correlated with the Cl− concentration, thereby suggesting that the extent of seawater intrusion might be one of the primary factors shaping bacterial composition in groundwater of this area, but the composition and distribution of archaea did not show a significant response to seawater intrusion and presented no apparent correlation with the Cl− concentration. α-, γ-Proteobacteria and Bacteroidota were the dominant bacterial lineages, accounting for about 58–95% of the bacterial communities. Meanwhile, the predominant archaeal taxa were mainly composed of Crenarchaeota, Nanoarchaeota, and Thermoplasmatota, as accounting for 83–100%. Moreover, there was significant spatial heterogeneity of microbial communities in the aquifers affected by varying degrees of seawater intrusion. The microbial communities inhabiting the unconfined aquifer were influenced by the geochemical fluctuation caused by seawater infiltration from land-based marine aquaculture ponds and the diffusion of eutrophic surface water. In contrast, changes in microbial community structure in the confined aquifers were closely related to the environmental gradient caused by different degrees of seawater intrusion. In addition, we also found that the tidal cycle did not significantly affect the structure of microbial communities inhabiting confined aquifers that had been long affected by seawater intrusion.

Recycling of rural abandoned constructed wetlands: mariculture wastewater treatment

AbstractThis study aimed to investigate the behavioral shifts of constructed wetland (CW) when the treated water was changed from domestic wastewater to mariculture wastewater. The results showed that the average removal efficiencies of ammonium nitrogen (), total nitrogen and chemical oxygen demand (COD) were 29.54, 46.07 and 57.15% in mariculture wastewater, respectively, which were significantly lower than those in domestic wastewater (71.35, 66.34 and 74.98%, respectively). While there was no significant difference in the removal efficiency of nitrate and phosphate (P > 0.05) between the two systems. Based on the analysis of bacterial community and adsorption properties, the results further indicated that the removal mechanism of between both systems was mainly due to substrate adsorption: the maximum adsorption capacity of on the substrate in mariculture wastewater was 5,432 mg kg−1, whereas that in domestic wastewater was 18,033 mg kg−1. In terms of bacterial communities, the dominant bacteria at the family level were Victivallaceae (18.63%) in domestic wastewater and Porphyromonadaceae (18.37%) in mariculture wastewater, which showed the significant alteration to the bacterial community. In conclusion, this study showed that conventional CW could be used for treating wastewater from land-based marine aquaculture, while the operating conditions needed to be optimized in the process of application.

Constructed Wetlands for Marine Aquaculture Wastewater Treatment: A New Challenge

Aquaculture is the fastest growing food production sector worldwide. Global demand for seafood continues to grow, and landbased aquaculture is expected to grow in order to meet the increasing market demand. In this context, marine aquaculture production systems are moving towards land-based farming. However, due to the large volumes of wastewater with high salinity and other fish-metabolism derived pollutants (e.g., nitrogen compounds), it remains a challenge for treatment of effluents from land-based marine aquaculture. In this scenario, development of environmental-friendly and efficient aquaculture effluent treatment system is crucial for sustainable intensification of aquaculture. Owing to low capital, operating costs, and low energy consumption, constructed wetlands (CWs) are becoming a promising technique to treat aquaculture effluents before discharge.

Efficiency of Salicornia neei to Treat Aquaculture Effluent from a Hypersaline and Artificial Wetland

In this study, we evaluated the potential of Salicornia neei, a halophyte plant native to South America, to treat saline effluents with simulated concentration of ammonium-N (Amm) and nitrate-N (Nit) in a similar manner to land-based marine aquaculture effluents. Plants were cultivated for 74 days in drainage lysimeters under three treatments of seawater fertilized with: (1) Nit + Amm, (2) Nit, or (3) without fertilizer (Control). Over five repetitions, nitrogen removal efficiency (RE) was high in both treatments (Nit + Amm = 89.6% ± 1.0%; Nit 88.8% ± 0.9%), whereas the nitrogen removal rate (RR) was nonlinear and concentration-dependent (RRday1–4: Nit + Amm = 2.9 ± 0.3 mg L−1 d−1, Nit = 2.4 ± 0.5 mg L−1 d−1; RRday5–8: Nit + Amm = 0.8 ± 0.2 mg L−1 d−1, Nit = 1.0 ± 0.2 mg L−1 d−1). Effluent salinity increased from 40.6 to 49.4 g L−1 during the experiment, with no observed detrimental effects on RE or RR. High nitrogen removal efficiency and significant biomass production were observed (Nit + Amm = 11.3 ± 2.0 kg m−2; Nit = 10.0 ± 0.8 kg m−2; Control = 4.6 ± 0.6 kg m−2) demonstrate that artificial wetlands of S. neei can be used for wastewater treatment in saline aquaculture in South America.

Ecological Engineering for the Optimisation of the Land-Based Marine Aquaculture of Coastal Shellfish.

Whilst the demand for nutritious and sustainable seafood is increasing, fishing yields are declining due to overfishing and climate change. The inshore aquaculture of marine molluscs—e.g., the suspension-feeding cockle Cerastoderma edule for NW Europe—might be an alternative practice if cost-effective and nature-based technology enhances growth and survival. Our inshore experiments revealed that increasing the seawater residence time resulted in improved water quality. The reduction in sediment loads and stimulation of pelagic microalgal growth resulted in enhanced shell growth and meat content of the wild cockles seeded into the system. Shorter residence times resulted also in an increase in benthic microalgae, but the concurrent increase in silt content of the sediment appeared to hamper effective filtration by cockles. The growth conditions (with respect to the water and sediment quality) for the inshore cultivation of cockles can indeed be improved by means of ecological engineering, suggesting that the inshore aquaculture of marine shellfish can provide sustainable food and income for coastal communities, in particular when the shellfish farms are located in low-lying salinized coastal areas where common agriculture practices are no longer profitable. The involvement of the shellfishery industry was and will be crucial for studying and understanding the complex practice of cockle cultivation.

Characterization of Microbial Communities in Pilot-Scale Constructed Wetlands with Salicornia for Treatment of Marine Aquaculture Effluents.

Microorganisms play an essential role in the performance of constructed wetlands (CWs) for wastewater treatment. However, there has been limited discussion on the characteristics of microbial communities in CWs for treatment of effluents from marine recirculating aquaculture systems (RAS). This study is aimed at characterizing the microbial communities of pilot-scale CWs with Salicornia bigelovii for treatment of saline wastewater from a land-based Atlantic salmon RAS plant located in Northern China. Illumina high-throughput sequencing was employed to identify the profile of microbial communities of three CWs receiving wastewater under different total ammonia nitrogen (TAN) concentrations. Results of this study showed remarkable spatial variations in diversity and composition of microbial communities between roots and substrates in three CWs, with distinct response to different TAN concentrations. In particular, Proteobacteria, Firmicutes, Cyanobacteria, and Bacteroidetes were predominant in roots, while Cyanobacteria, Proteobacteria, Firmicutes, Verrucomicrobia, and Bacteroidetes were prevalent in substrates. Moreover, redundancy analysis indicated that specific functional genera, such as Nitrosopumilus, Vibrio, Pseudoalteromonas, Nitrospina, and Planctomyces, played key roles in the removal of nitrogen/phosphorus pollutants and growth of wetland plants. From a microorganism perspective, the findings of this study could contribute to better understanding of contaminants' removal mechanism and improved management of CWs for treatment of effluents from land-based marine aquaculture.

Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 9:445-460 (2017) - DOI: https://doi.org/10.3354/aei00244 REVIEW Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges Marco Custódio1,*, Sebastian Villasante2, Javier Cremades3, Ricardo Calado1, Ana I. Lillebø1 1Department of Biology & CESAM & ECOMARE, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal 2Faculty of Political Sciences, University of Santiago de Compostela, 15782 Santiago de Compostela, A Coruña, Spain 3Centre for Advanced Scientific Research (CICA), University of A Coruña, 15071 A Coruña, Spain *Corresponding author: mfc@ua.pt ABSTRACT: The present study critically analyses peer-reviewed literature addressing the potential of halophytes to remediate nutrient-rich effluents from marine and coastal aquaculture, as well as the potential for their economic valorization, from human consumption to an untapped source of valuable secondary metabolites with pharmaceutical potential. The growing body of evidence discussed in this review supports the perspective that halophytes can become a new source of nutrition and other high-value compounds and be easily incorporated into saltwater-based integrated multi-trophic aquaculture (IMTA) systems. In this context, halophytes act as extractors of dissolved inorganic nutrients, primarily nitrogen and phosphate, usually wasted in marine aquaculture farms. Phytoremediation using halophytes has been proven to be an efficient solution, and several ways exist to couple this practice with land-based marine aquaculture systems, namely through constructed wetlands and aquaponics. Focusing research on ecosystem-based approaches to aquaculture production will provide valuable data for producers and policy makers in order to improve decision making towards a sustainable development of this economic sector. Eco-intensification of aquaculture through IMTA will potentially increase the overall productivity and resilience of the sector, and halophytes, in particular, are on the verge of becoming key players for the diversification and promotion of land-based IMTA. This work specifically documents the uncharted potential of Halimione portulacoides, an important halophyte in European salt marsh ecosystems, as a new extractive species for IMTA. KEY WORDS: Sustainable aquaculture · Bioremediation · Dissolved nutrients · Coastal IMTA · Saltwater aquaponics · Blue growth · Circular economy Full text in pdf format Supplementary material PreviousCite this article as: Custódio M, Villasante S, Cremades J, Calado R, Lillebø AI (2017) Unravelling the potential of halophytes for marine integrated multi-trophic aquaculture (IMTA)— a perspective on performance, opportunities and challenges. Aquacult Environ Interact 9:445-460. https://doi.org/10.3354/aei00244 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 9. Online publication date: November 22, 2017 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2017 Inter-Research.

Characterization of a microbial consortium that converts mariculture fish waste to biomethane

Environmentally responsible disposal of solid organic wastes from land-based brackish and marine recirculating aquaculture systems is critical for promoting widespread acceptance and implementation, but conversion efficiency of saline sludge to biomethane is generally low. We describe the development of a microbial consortium that can convert marine organic fish waste solids to biomethane at over 90% efficiency. The halotolerant microbial consortium, which was developed by sequential transfer in seawater with fish waste, is optimized for low COD:N ratios typical of organic fish waste and does not require addition of amendments such as organic carbon or nutrients. Temperatures for maximum rates of conversion range from 26 to 35°C. Five predominant phylotypes identified in the microbial consortium by denaturing HPLC were isolated. Two isolates included anaerobic fermentative bacteria identified as a strain of Dethiosulfovibrio and a strain closely related to Fusobacterium spp., which both hydrolyze and ferment proteins, peptides and amino acids. The other three isolates included an acetate-utilizing methanogenic archaeon identified as a strain of Methanosarcina and two hydrogen-utilizing methanogenic archaea identified as strains of Methanogenium and Methanoplanus. Bioconversion rates of sterile fish waste with the reconstituted microbial consortium containing all five isolates were equivalent to rates observed with the original enriched consortium after one sequential transfer. The results demonstrate unequivocally that halotolerant consortia of bacteria and archaea can be developed for bioconversion of saline organic solid waste with high efficiencies equivalent to those attained with non-saline waste systems. Understanding the microbial community composition is critical for management of solid organic waste from land-based marine aquaculture systems and to maintain or restore microbiota during start up and throughout the production process. Statement of relevanceAppropriate disposal of solid organic wastes from land-based brackish and marine recirculating aquaculture systems is critical for promoting widespread acceptance and implementation. We demonstrate that halotolerant consortia of bacteria and archaea can be developed for bioconversion of saline fish waste with high efficiencies equivalent to those attained with non-saline waste systems.

Implementation of a minimal set of biological tests to assess the ecotoxic effects of effluents from land-based marine fish farms

Environmental monitoring plans (EMP) that include chemical analysis of water, a battery of bioassays and the study of local hydrodynamic conditions are required for land-based marine aquaculture. In this study, the following standardized toxicity tests were performed to assess the toxicity of effluents from eight land-base marine fish farms (LBMFFs) located on the northwest coast of Spain: bacterial bioluminescence (with Vibrio fischeri at 15 and 30min), microalgal growth (with Phaeodactyllum tricornutum and Isochrysis galbana) and sea urchin larval development (with Paracentrotus lividus and Arbacia lixula). These bioassays were evaluated for inclusion in routine fish farm monitoring. Effective concentrations (EC5, EC10, EC20, EC50) for each bioassay were calculated from dose–response curves, obtained by fitting the bioassay results to the best parametric model. Moreover, a graphical method of integrating the results from the battery of bioassays and classifying the toxicity was proposed, and the potential ecotoxic effects probe (PEEP) index was calculated. The bacterial bioluminiscence test at 30min, growth of I. galbana and larval development of A. lixula were found to be the most sensitive and useful tests. Graphical integration of these test results enabled definition of the ecotoxicological profiles of the different farms. The PEEP index, considering EC20, efficiently reflected the toxic loading potential of LBMFF effluents. In conclusion, a battery of bioassays with species from different low trophic levels is recommended as a rapid and cost-effective methodology for assessing LBMFF discharges. The graphical integration method and the PEEP index are proposed for consideration in EMPs for such farms.

Evaluating the economic potential of horizontally integrated land-based marine aquaculture

Coastal aquaculture development is frequently associated with negative environmental impacts, competition for resources and conflict. Consequently, a new paradigm of ecologically-sound, socially responsible and economically viable aquaculture development based on systems-thinking, resource use efficiency and joint analysis with stakeholders is needed. Horizontal integration, combining aquaculture production systems to optimise resource use efficiency constitutes a promising approach in this regard. Research shows that an array of horizontally integrated systems are technically viable, however, few studies have combined this with consideration of the managerial, financial and economic demands. A bioeconomic modelling approach was employed here to assess the broader implications of adopting horizontally integrated land-based marine aquaculture in temperate and warm water settings. The temperate system, integrating fish, microalgae and shellfish culture and a polishing lagoon was developed on the Atlantic coast of France. Modelling outcomes predicted that when all costs were considered this approach failed to generate a positive Internal Rate of Return (IRR) over ten years. Subsequent scenarios showed a worthwhile return (ten-year IRR 19.4%) was generated when land and labour opportunity costs were omitted and a 20% premium on products included. The warm water system developed near Eilat, Israel combined sea urchins, shrimp and seaweed culture with a constructed wetland. Assuming baseline production of one million sea urchins annually from year three onwards, modelling outcomes showed a reasonable ten-year IRR of 18%. Reducing sea urchin mortality from 15% to 9% annually resulted in an IRR of 29.4%, while assuming that Salicornia spp. production would reach 33 kg m−2 y−1 in the wetland resulted in an IRR of 133.4%. Findings suggest that bioeconomic modelling can contribute to the optimisation of horizontally integrated aquaculture systems, helping elucidate promising scenarios and identify key constraints and priorities for targeted research and development. Bioeconomic modelling of other horizontal integration strategies, such as shrimp culture with shellfish, macroalgae and mangrove wetlands could elucidate economically viable approaches to much needed ecologically-sound and socially responsible practices. However, modelling should be supplemented by market analysis, including assessment of consumer attitudes, comprehensive risk assessment, ethical review, environmental impact assessment and joint assessment with stakeholders. Moreover, an enabling institutional framework is a prerequisite to more widespread adoption of horizontal integration; policy initiatives and regulatory tools focused on internalising environmental costs of aquaculture development will be critical.

Environmentally sustainable land-based marine aquaculture

Reduced fishery harvests and increased consumer demand for seafood have precipitated an increase in intensive fish farming, predominantly in coastal and open ocean net-pens. However, as currently practiced, aquaculture is widely viewed as detrimental to the environment and typical operations are vulnerable to environmental influences, including pollution and endemic diseases. Here we report the development of a land-based, marine recirculating aquaculture system that is fully contained, with virtually no environmental impact as a result of highly efficient biological waste treatment and water recycling. Over 99% of the water volume was recycled daily by integrating aerobic nitrification to eliminate toxic ammonia and, for the first time, simultaneous, anaerobic denitrification and anaerobic ammonium oxidation, to convert ammonia and nitrate to nitrogen gas. Hydrogen sulfide generated by the separated endogenous organic solids was used as an electron source for nitrate reduction via autotrophic denitrification and the remaining organic solids were converted to methane and carbon dioxide. System viability was validated by growing gilthead seabream ( Sparus aurata) from 61 g to 412 g for a total of 1.7 tons in a record 131 days with 99% fish survival. Ammonia nitrite and nitrate did not exceed an average daily concentration of 0.8 mg/l, 0.2 mg/l and 150 mg/l, respectively. Food conversion values were 16% lower than recorded levels for net-pen aquaculture and saltwater usage of less than 16 l/every kg of fish produced. The system is site-independent, biosecure, devoid of environmental contaminants and is not restricted to a single species.

Enhanced production of Pacific dulse ( Palmaria mollis) for co-culture with abalone in a land-based system: effects of stocking density, light, salinity, and temperature

Palmaria mollis or Pacific dulse is used as both a biofilter and feed in temperate, land-based marine aquaculture of abalone and finfish. Land-based tumble-culture techniques capable of producing commercial quantities of P. mollis are still in development. In this study the effects of stocking density, light, salinity, and temperature on growth rates and yields of P. mollis were examined. Under a natural photon flux density (PFD) of 39–52 mol photons m −2 day −1 an aerial stocking density of 3–4 kg m −2 provided highest yields. Specific growth rates of P. mollis were highly correlated with specific light densities (SLD) over a range from 0.0048 to 0.036 mol photons g −1 [fresh wt.] day −1 and no light saturation was evident at a culture temperature of 16±1 °C. Growth of P. mollis was highest at a salinity of 30±1‰, whether municipal tap water or brackish well water was used for diluting seawater. Optimal temperature for growth was 12 °C at low light intensities (SLD=0.010 mol photons g −1 day −1) and 14–18 °C at high light intensities (SLD=0.021 mol photons g −1 day −1). Growth at higher temperatures was positively correlated with increasing light. Lowering culture temperature at night from 15 to 11 °C significantly increased growth for cultures that were not supplied with supplemental inorganic carbon.

Energy use in controlled temperature marine aquaculture

Temperature control offers benefits in land-based marine aquaculture: stock growth rates may be enhanced by heating in winter; mortality rates in summer may be reduced by cooling. However, if the plant is not well designed, temperature control may create very large energy demands. This paper describes the application of temperature control in abalone aquaculture in New Zealand, with a focus on energy considerations in plant design. An abalone farm using a semi-closed water conditioning system is used as a case study for which an energy model, based on a heat pump system, is developed. The model is used to determine the impact of plant design and tank conditions on the economics of the operation. Copyright © 2002 John Wiley & Sons, Ltd.