Improving biosecurity: a necessity for aquaculture sustainability
25 September 2010 | Mike Hine | 1658 views | .mp3 | 15.92 MB | Health and welfare, Ornamentals
More than 200 species are produced in aquaculture worldwide; some 25 of these are of high value and traded globally. A successful harvest can be very profitable, and this has spurred the expansion of aquaculture production in both area and geographical range. Species movement for farming, when done in a haphazard manner, can be one of the many sources of biological threats to the well-being of farmed aquatic animals, as well as that of humans and ecosystems. As aquaculture intensifies and diversifies, the biological hazards and risks to farmed animals, people and ecosystems also increase in number and diversity, with serious consequences. Some of these are infectious diseases, animal pests, public health concerns on residues and resistance of antimicrobial agents, zoonoses, invasive alien species, release of genetically modified organisms (GMOs) and biosecurity risks posed by climate change. The growing number, complexity and seriousness of these risks have driven the development of the concept of biosecurity and its increasing application in many food-producing sectors, including agriculture. FAO defines biosecurity as a strategic and integrated approach that encompasses the policy and regulatory frameworks that analyse and manage risks in the sectors of food safety, animal and plant life and health, including associated environmental risk. An integrated strategy to manage biosecurity, business, environmental and social risks will better promote sustainable growth of the sector.
Transboundary aquatic animal diseases (TAADs) may occur due to illegal introductions and transfers of live animals, lack of controls on movements, inability to detect potential pathogens in apparently healthy animals and the ornamental fish trade, which is now recognised as an important pathway for disease dissemination. Many marine invasive pests are now recognised, the majority of which are linked to a transport vector, particularly shipping, with some being associated with hull fouling and ballast water. Other movements may be due to fisheries stocking, live seafood trade and movement of species for aquaculture, bio-control and scientific research. Food safety concerns in aquaculture include antimicrobial and chemical residues and live human parasites such as food-borne trematodes. While vaccination may reduce the use of antimicrobial agents, some vaccines with adjuvants may impact on animal welfare. Although the use of antimicrobial agents may result in resistance among targeted bacteria, there is so far no evidence of effects on human health. Veterinary medicinal products are being developed to overcome residue problems and minimise food safety risks. While GMOs may be beneficial with regard to increased production, disease and freeze resistance, and reproductive sterility, large-scale escape from confinement may cause genetic replacement of local stocks.
Many of these issues, however, are being addressed at varying degrees and different levels. For example, national strategies and policy frameworks to control TAADs have been developed in Australia, North America and Asia and are being formulated in Latin America and the Caribbean (LAC), as well as southern Africa. Some of the important elements of such frameworks include, for example, disease diagnosis, quarantine considerations, surveillance and reporting, adoption and implementation of OIE standards and other voluntary guidelines, and emergency preparedness. These are supported by educational and extension programmes, development of resource materials, establishment of reference and competent laboratories, and provision of technical assistance at the farm/local/national/regional levels. New developments in diagnostic techniques, such as serological detection of koi carp herpes virus, lateral flow technology for infectious salmon anaemia and white spot disease of shrimp, and molecular genomics all improve diagnostic capacities, thus reducing the risk of TAADs.
At the heart of the modern approaches to biosecurity is the application of risk analysis. It offers an effective management tool where pragmatic decisions can be made that provide a balance between competing environmental and socio-economic interests, despite limited information. This tool, however, needs research, databases and other vital sources of information and knowledge so that it can effectively support biosecurity assessments, surveillance, diagnostics, early warning and contingency planning.
Sections 3.11 (managing aquatic animal health), 3.13 (applying genetics to aquaculture), 3.14 (applying biotechnology) and 3.15 (improving food quality and safety) of the 2000 Bangkok Declaration are all relevant to biosecurity. Traditionally such concerns have been addressed using the sectoral approach to biosecurity, and what is lacking is a holistic systems approach to aquatic animal health management and biosecurity. Also missing from the declaration are specific references to invasive pests, particularly in relation to ships’ ballast water and hull fouling, aquatic plants and the global trade in ornamental animals, now seen as a major loop-hole in attempts to control TAADs.
Effective, coordinated and proactive biosecurity systems are the product of science-based knowledge and practices used within effective regulatory frameworks that are backed by sufficient resources for enforcement. As aquaculture becomes more intensive, new diseases and other problems are likely to emerge, and old diseases will appear in new locations. Aquaculture biosecurity will continue to operate at three levels: a) internationally, as recognised in the Bangkok Declaration; b) regionally, as seen through various regional activities; and c) on a small scale where variables (environment, species cultured, funding, training, economics) differ within countries in a region. A crucial consideration is how to deal with “unknowns”. The need to forge an effective regional and international cooperation to pool resources and share expertise and information will be essential. At the global, regional or national levels, the institutions mandated to ensure biosecurity would be served well by putting emergency preparedness with advanced financial planning as their core function.
This session will take a broad spectrum approach on as many aspects of biosecurity as possible and will identify successes and failures, issues of importance to regions and the role of biosecurity in the sustainable increase in aquaculture production. Hopefully, it will result in linkages between groups to tackle or solve specific problems. Ideas will be canvassed on what needs to be achieved over the next ten years. There are several likely trends. New technologies will permit accurate and rapid pond-side diagnosis of disease and simultaneous testing for multiple pathogens that would greatly benefit the detection of multiple asymptomatic viral infections in shrimp and permit tighter controls on movement of these infections. Veterinary pharmaceutical companies will work closely with the aquaculture industries to provide more efficacious, safe, rapid and cost-effective treatments designed specifically for aquaculture. Animal welfare is likely to become an issue in aquaculture, particularly with increased intensive farming. Just as there has been impressive capacity building in biosecurity in Asian aquaculture and its nascent development in LAC and Africa, these processes must continue to improve and spread to other continents as aquaculture develops. We will also see more interaction between aquaculture fish health specialists and veterinary practitioners, supported by appropriate certification schemes that will enable provision of effective biosecurity services and guidance to the sector. Climate change scenarios (e.g. sea level rise, increased incidence of storm surges and land-based run-offs, extreme weather events, etc.) that may affect biosecurity (e.g. by increasing range of pests and pathogens, intensities of their occurrence and vulnerabilities of farmed animals to diseases) will also be significant and will need to be addressed.
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