Sustainable aquaculture and aquatic resources management

By Craig Browdy, 23/09/2010 | .mp3, 13.45 MB | 1236 views | Download soundtrack Stream soundtrack
Programme: Global Conference on Aquaculture 2010

Aquaculture continues to be the fastest growing food production sector, representing great potential to meet projected protein needs of world populations. As aquaculture expands, examples demonstrate potential to improve economic and social wellbeing while producing needed wholesome food. On the other hand, some less responsible development has drawn attention to potential problems with social, environmental and financial sustainability. The scientific and business communities have responded to these challenges and opportunities with research efforts generating novel technologies mirroring the diversity of the industry.

In genetics and breeding, the pace of advancement and innovation has been increasing exponentially. Although >20 percent of aquaculture production today derives from selective breeding programmes, many successful sectors are now based on selection programmes including trout, salmon, tilapia and shrimp. The number of breeding programmes, diversity of species, target traits and efficiency and sophistication of techniques applied continue to expand and advance. Tools for exploring the genetic code including marker technologies, genome mapping, and even full genome sequencing are being applied to aquaculture species. Improved sequencing genetic libraries are enabling genomic tools to explore responses to disease, metabolic processes and production traits. Gene transfer techniques have been applied to aquaculture species, and enhancement of growth, disease resistance and cold tolerance has been demonstrated. However, the pace of scientific development has at times outdistanced our ability to analyse risks and benefits, develop appropriate culture and containment technologies, educate and communicate, and reach policy and regulatory consensus. Now more than ever, efforts must be made for society to accurately analyse and understand risks, to enable opportunities to raise healthier fish faster with less environmental impact while improving economic stability and providing associated social benefits.

Disease outbreaks continue to constrain aquaculture sustainability. Improvements in aquatic animal health are coming from new technologies and improved management strategies. Better understanding of the genetic and physiological basis of immunity is enabling the breeding and husbandry of cultured stocks for improved disease resistance. Vaccine development is benefiting from better specific antigen determination, more efficacious adjuvants and enhanced vaccine delivery. Traditional diagnostic technologies and newer methods including immunodiagnostics, florescence antibody, ELISA, immunochromatography and nucleic acid-based approaches such as in-situ hybridisation, PCR and qPCR have greatly improved speed, specificity and sensitivity. As the sophistication of the tools and access to on-farm rapid diagnostics improve, expanding training, infrastructure and certification of aquatic veterinary and pathology support grows in importance. Research on improving oral delivery and control of active ingredients, new medical products from plants, vaccination and integration of disease management strategies that focus on prevention offer opportunities for improved control of pathogens in the future, obviating the use of antibiotics and chemotherapeutants. The use of multiple tactics against infection, farm-based strategies, improved local availability of healthy stocks, effective regulation of drugs and chemicals and policies to minimise disease transfer will be major steps towards sustainability.

An important key to the culture of any fed species is the development of a sustainable, cost-effective and nutritionally complete feed. Research has focused on shifting from formulations based on ingredients to strategies based on nutrient availabilities and specific requirements. Continuing cost pressures and the acute need to replace the high levels of fish meals and fish oils in many aquaculture feeds are driving a transition to more sustainable feeds. Fish meal extension in aqua feeds requires a blend of technologies to meet high protein and specific amino acid requirements, supply essential fatty acids and overcome lower tolerance to carbohydrates and anti-nutritional factors, while maintaining palatability and physical properties. Development and testing of water-stable sources of crystalline amino acids, organic minerals that do not bind with agonists like phytic acid, attractants and effective oil blends are all part of emerging solutions. Protein concentrates and enzyme or heat pre-treatment, and the use of genetically selected feedstuffs with reduced anti-nutritional compounds will provide options for formulators. High-quality rendered animal products can be an excellent source of protein and lipid if regulatory policies and market education enable use. New sources of proteins and oils from algae and microbes can offer alternatives as cost efficiencies improve. Use of enzymes, probiotics and prebiotics, phytogenic compounds and organic acids are being shown to change gut microflora and improve health, digestibility and performance. Improved pelleting and extrusion technologies along with attention to fine grinding, pre-treatment, manufacturing and drying temperatures distinguish top quality feeds. Application of post-pelleting technologies such as vacuum coating has allowed feed production with higher lipid content and enables addition of enzymes, attractants, carotenoids and other heat-labile supplements. Expanding use of floating feeds for top-feeding fish can improve sustainability by increasing efficiency of delivery.

Production systems technology advancements are also contributing to sustainable industry expansion. Recirculation technologies are improving with automated life support systems, improved waste recycling, specialised feeds and better efficiencies based on sustainability metrics. Shellfish production research is advancing reproductive control, larval production, health, predator deterrence and bio-fouling control. Cage production is benefitting from improved automation, integrated disease and parasite control, advanced engineering, feeds and feeding systems, and monitoring of environmental performance. Technologies for rearing disease-free, genetically improved shrimp and tilapia in reduced exchange biofloc-based pond and tank systems enable in-situ cycling of wastes, improving feed conversion efficiency, and reducing environmental impacts while enhancing biosecurity, health and cost efficiencies. Research work on integrated multitrophic aquaculture focuses on application of ecosystem-based approaches to integrate fed aquaculture (e.g. finfish) with organic extractive aquaculture (e.g. shellfish) and inorganic extractive aquaculture (e.g. seaweeds). All of these production system technologies are benefitting from expanding information and communication systems that are enabling advances in every stage of production. These and other examples suggest some of the benefits that future scientific-based innovation will contribute towards meeting increasing food demands, while improving social, environmental and financial sustainability of the global aquaculture industry.



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