Microalgal cultivation in aquaculture wastewater (AWW) from recirculating aquaculture systems (RAS) is an approach for combined production of valuable algal biomass and AWW treatment. The growth, ...nutrient uptake, fatty acid (FA) profile, and tocopherol content of mixed algal cultures of
Euglena gracilis
with
Selenastrum
grown in AWWs from pikeperch (
Sander lucioperca
) and catfish (
Clarias anguillaris
) RAS were studied. The highest algal biomass (1.5 g L
−1
), lipid (84.9 mg L
−1
), and tocopherol (877.2 μg L
−1
) yields were achieved in sludge-amended pike perch AWW. Nutrient removal rates in experiments were 98.9–99.5 and 98.4–99.8% for NH
4
-N and PO
4
-P, and 75.4–89.2% and 84.3–95.7% for TN and TP, respectively, whereas the COD was reduced by 45.8–67.6%. Biomass EPA and DHA content met, while ARA and tocopherol content exceeded the requirements for fish feed. Algal cultivation in AWWs is a promising alternative for AWW treatment while providing a replacement for fish oil in feed.
Marine aquaculture presents an opportunity for increasing seafood production in the face of growing demand for marine protein and limited scope for expanding wild fishery harvests. However, the ...global capacity for increased aquaculture production from the ocean and the relative productivity potential across countries are unknown. Here, we map the biological production potential for marine aquaculture across the globe using an innovative approach that draws from physiology, allometry and growth theory. Even after applying substantial constraints based on existing ocean uses and limitations, we find vast areas in nearly every coastal country that are suitable for aquaculture. The development potential far exceeds the space required to meet foreseeable seafood demand; indeed, the current total landings of all wild-capture fisheries could be produced using less than 0.015% of the global ocean area. This analysis demonstrates that suitable space is unlikely to limit marine aquaculture development and highlights the role that other factors, such as economics and governance, play in shaping growth trajectories. We suggest that the vast amount of space suitable for marine aquaculture presents an opportunity for countries to develop aquaculture in a way that aligns with their economic, environmental and social objectives.
Identifying strategies to maintain seafood supply is central to global food supply. China is the world's largest producer of seafood and has used a variety of production methods in the ocean ...including domestic capture fisheries, aquaculture (both freshwater and marine), stock enhancement, artificial reef building, and distant water fisheries. Here we survey the outcomes of China's marine seafood production strategies, with particular attention paid to the associated costs, benefits, and risks. Benefits identified include high production, low management costs, and high employment, but significant costs and risks were also identified. For example, a majority of fish in China's catches are one year-old, ecosystem and catch composition has changed relative to the past, wild and farmed stocks can interact both negatively and positively, distant water fisheries are a potential source of conflict, and disease has caused crashes in mariculture farms. Reforming China's wild capture fisheries management toward strategies used by developed nations would continue to shift the burden of production to aquaculture and could have negative social impacts due to differences in fishing fleet size and behavior, ecosystem structure, and markets. Consequently, China may need to develop novel management methods in reform efforts, rather than rely on examples from other large seafood producing countries. Improved accounting of production from fisheries and aquaculture, harmonization and centralization of historical data sets and systematic scientific surveys would improve the knowledge base for planning and evaluating future reform.
Aquaculture is the main source to increase fish supply. Fast development of aquaculture and increasing fish demand lead to intensification of fish culture, magnifying stressors for fish and thus ...heightening the risk of disease. Until now, chemotherapy has been widely used to prevent and treat disease outbreaks, although use of chemical drugs has multiple negative impacts on environment and human health e.g. resistant bacterial strains and residual accumulation in tissue. Hence, disease management in aquaculture should concentrate on environmentally friendly and lasting methods. Recently, increasing attention is being paid to the use of plant products for disease control in aquaculture as an alternative to chemical treatments. Plant products have been reported to stimulate appetite and promote weight gain, to act as immunostimulant and to have antibacterial and anti-parasitic (virus, protozoans, monogeneans) properties in fish and shellfish aquaculture due to active molecules such as alkaloids, terpenoids, saponins and flavonoids. However, as it is a relatively emerging practice there is still little knowledge on the long-term effects of plant extracts on fish physiology as well as a lack of homogenization in the extract preparation and fish administration of the plant extracts. This article aims to review the studies carried out on the use of plant products on fish aquaculture and their biological effects on fish such as growth promoter, immunostimulant, antibacterial and anti-parasitic. It also intends to evaluate the current state of the art, the methods used and the problems encountered in their application to the aquaculture industry.
•Disease management in aquaculture needs of more environmentally friendly methods.•There is an increasing use of plant extracts in aquaculture for disease control.•Use of plant extracts in aquaculture needs normalization to assure their efficacy.•Algae natural products present a huge potential in aquaculture disease treatment.
Pond aquaculture undeniably offers the potential for food production worldwide. In China, 45.83% of aquatic production is currently from pond aquaculture. However, with the continuous expansion of ...this practice, environmental problems such as a high level of water consumption, aquaculture water deterioration, pollution from effluent and aquatic product quality decline seriously restrict the sustainable development of pond aquaculture. In this review, we summarise the (i) the impacts of pond aquaculture on the environment, (ii) research progress in pond aquaculture ecological engineering, (iii) existing technologies regarding pond aquaculture ecological engineering systems, (iv) effects of applying pond aquaculture ecological engineering and (v) summary and prospects. Moreover, we discuss the merits and drawbacks of each method and technology, and future research priorities are reviewed. With this, an understanding of the role played by ecological engineering in pond aquaculture is provided, as well as guidance for precisely managing aquaculture water and effluent, aquaculture practices, and technological developments. In summary, the pond aquaculture ecological engineering can be managed so as to improve animal welfare and the stability of water treatment systems, reducing the adverse effects on the environment and public health, and enabling the sustainable development of pond aquaculture.
The FAO recently published its biennial State of World Fisheries and Aquaculture up to 2018. The FAO continues to treat the seaweed aquaculture sector as a different category, with separate tables ...and comments in different sections. As this could lead to a distorted view of total world aquaculture, the statistical information provided by FAO was revisited and data regarding the seaweed aquaculture sector were integrated with data of the other sectors of the world aquaculture production, to reach different conclusions: (1) aquaculture represents 54.1% of total world fisheries and aquaculture production; (2) marine and coastal aquaculture represents 55.2% of total world aquaculture production; (3) seaweeds represent 51.3% of total production of marine and coastal aquaculture; (4) 99.5% of seaweed mariculture production is concentrated in Asia; (5) 8 seaweed genera provide 96.8% of world seaweed mariculture production; (6) 2 seaweed genera are the most produced organisms in mariculture in the world; (7) the value of the seaweed aquaculture sector could be much larger, especially if a monetary value was attributed to the ecosystem services provided by seaweeds; and (8) total extractive aquaculture is slightly larger (50.6%) than total fed aquaculture (49.4%).
Summary
The worldwide growth of aquaculture has been accompanied by a rapid increase in therapeutic and prophylactic usage of antimicrobials including those important in human therapeutics. ...Approximately 80% of antimicrobials used in aquaculture enter the environment with their activity intact where they select for bacteria whose resistance arises from mutations or more importantly, from mobile genetic elements containing multiple resistance determinants transmissible to other bacteria. Such selection alters biodiversity in aquatic environments and the normal flora of fish and shellfish. The commonality of the mobilome (the total of all mobile genetic elements in a genome) between aquatic and terrestrial bacteria together with the presence of residual antimicrobials, biofilms, and high concentrations of bacteriophages where the aquatic environment may also be contaminated with pathogens of human and animal origin can stimulate exchange of genetic information between aquatic and terrestrial bacteria. Several recently found genetic elements and resistance determinants for quinolones, tetracyclines, and β‐lactamases are shared between aquatic bacteria, fish pathogens, and human pathogens, and appear to have originated in aquatic bacteria. Excessive use of antimicrobials in aquaculture can thus potentially negatively impact animal and human health as well as the aquatic environment and should be better assessed and regulated.
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