Aquaculture contributes significantly to affordable, high-quality, animal protein and other essential nutrients, especially for poorer segments of the world. However, disease is a serious constraint to the sustainable culture of many species, impeding socio-economic progress in many countries. As a result, aquatic animal health programmes based on surveillance and zonation for diseases of national and international trade significance have become a primary requirement for effective management of sustainable aquaculture development in many countries.
Outlines for aquatic animal health programmes are provided by the Aquatic Animal Health Code (OIE 2003b) and the Manual of Diagnostic Tests for Aquatic Animals (OIE 2003c) of the World Organisation for Animal Health (OIE), as well as by Asia-Pacific regional aquaculture health infrastructure support documents of the FAO and the Network of Aquaculture Centres of Asia-Pacific (NACA), including a Technical Guidelines and Implementation Strategy (FAO/NACA 2000), Manual of Procedures (FAO/NACA 2001) and an Asia Diagnostic Guide (Bondad-Reantaso et al. 2001). All documents take into full consideration the provisions of the World Trade Organizations Agreement on the Application of Sanitary and Phytosanitary Measures (WTO-SPS Agreement) (WTO 2002), along with Article 9 (Aquaculture Development) of the Code of Conduct for Responsible Fisheries (CCRF) (FAO 1995).
The OIE Aquatic Code recommends that zones for diseases of concern to international trade be established to internationally accepted standards with regard to terminology, boundaries, legal competence, duration of disease free periods, standards of surveillance, use of buffer zones, quarantine procedures and other aspects of regulatory control.
It is the responsibility of the Competent Authorities (CA) of countries wishing to implement zonation to demonstrate that they have a reliable system of disease control and surveillance in place. The design and implementation of such systems under a wide range of aquatic situations, however, has highlighted both technical and economic challenges for realistic and scientifically justifiable surveillance programmes. This is particularly complex for open-water marine environment zonation, but also poses problems for multijurisdictional freshwater and estuarine hydrographic areas.
In the context of this Expert Consultation, surveillance and zonation are applicable to diseases of concern to trade, to disease management and control within individual countries, as well as to management spanning a range of jurisdictional (provincial, state, territory) and geographic boundaries. In the latter situations, disease control frameworks have frequently used political boundaries, rather than epidemiological, climatic or hydrographic boundaries, to define zones. These have proven ineffective and are subject to inconsistencies and unscientific decision-making. As more countries start to develop their own aquatic animal health programmes, it is important to define the process for listing the diseases of concern. Without such definitions, the justification for the significant investment of resources and infrastructure required will continue to be argued among policy and decision makers.
While recommending establishment of zones for aquatic animal disease management, FAO and OIE recognize that most countries face significant challenges in the practical implementation of zonation. In addition to scientific capability, political will and economic support are required. Scientifically sound surveillance programmes are often costly investments. The economic benefits of such programmes have to be weighed against each countrys aquaculture activities - especially live aquatic animal movements. The regulatory jurisdictions of governments involved in aquaculture development, as well as protection of wild aquatic resources, must be taken into account to ensure optimum partnership (stakeholder) involvement in disease management in its broadest ecological sense.
In an effort to determine what surveillance options can best support scientifically valid zonation frameworks, the Federal Department of Fisheries and Oceans Canada (DFO Canada) in 2002 offered assistance to FAO in order to hold an Expert Consultation on the question of Surveillance and Zonation.
Objective: The objective of the Expert Consultation was to provide recommendations for surveillance and zonation that will be useful for designing national programmes aimed at reducing the risks of disease losses through live transfers of aquatic animals. These recommendations are aimed solely at providing scientific advice to member countries building national or regional aquatic animal health infrastructures. They are not intended for use as international trade guidelines or standards (the remit of the WTO and OIE).
Approach: The three levels of diagnostics (Levels I, II, III) used throughout this Technical Paper were developed for the Asia Regional Technical Guidelines, the Manual of Procedures and the Asia Diagnostic Guide to Aquatic Animal Diseases. These span all levels of aquatic disease experience, technology and related infrastructures.
Thematic organization: The Expert Consultation consisted of presentations and discussions in both plenary and sub-group sessions. Sub-groups consisted of experts in specific aquatic animal groups and habitats (duly noting that some diseases may span more than one habitat):
Finfish - marine, freshwater, diadromous
Molluscs - marine, estuarine
Crustaceans - marine, freshwater, estuarine
Criteria taken into consideration were: type of disease and host(s); duration of production cycles; wild and hatchery-based production; production systems and marketing; sampling options (collection methods, transportation conditions, etc.); reporting options; and data management. These were discussed in light of scientific (confidence levels) and legal (transparency) challenges at the international level (assuming this will cover national/regional or local disease management objectives).
Scope and base-line assumptions: Consultation discussions were limited to surveillance and zonation strategies, despite obvious linkages to diagnostic methodology (sensitivity and specificity questions, field validation, etc.), quality assurance/quality control management of surveillance protocols, disease response/control mechanisms, and others. Such restriction in scope was necessary in order to focus on the basic design of sampling programmes, rather than on their technological or regulatory foundations. This required a clear understanding, and recognition, of several base-line assumptions. These should be considered by any aquatic animal health interests using the resulting recommendations of this Expert Consultation. These base-line assumptions are:
screening technology used is effective for detection of the disease agent in question, under normal environmental and culture conditions;
a Quality Assurance/Quality Control (QA/QC) programme is in place to monitor the effectiveness of the screening technology used;
all diseases have a sub-clinical stage of development that can escape detection using optimum screening methodology;
all susceptible and/or carrier species are unlikely to be known.
Procedure: Five working documents were prepared by selected experts and provided the basis for discussion and development of recommendations during the Consultation. Four working documents addressed the technical issues that required discussion for: (a) freshwater finfish, (b) marine and diadromous finfish, (c) crustaceans; and (d) molluscs. The capacity building, information access and technical requirements of developing countries wishing to implement surveillance and zonation for aquatic animal diseases formed a fifth, non-technical, discussion document.
Participants: Participants were selected on the basis of technical experience and knowledge of surveillance, zonation and epidemiology (See Appendix II). Representation from the agricultural disease control field was included to compare surveillance approaches used for terrestrial animal diseases. Every effort was also made to include representation from various regions of the world to cover the breadth of environmental and aquatic resource sectors faced in developing surveillance and zonation programmes.
Venue and date: FAO-UN headquarters, Rome, Italy, 14-16 October 2002. See Appendix III for the Consultation Work Programme.
Dr Rohana P. Subasinghe
Dr Sharon E. McGladdery
Dr Barry J. Hill
 Seasonal detection
sensitivity was taken into account for collection scheduling.|