Aquaculture Newsletter

(December 1996, Number 14)

The Use of Chemicals in Aquaculture: A Summary Brief of Two International Expert Meetings

Uwe Barg¹ and Celia R. Lavilla-Pitogo²
¹ Fishery Resources Division, FAO
² Aquaculture Department, SEAFDEC

The use of chemicals is common in various aquaculture systems, as it is in many agricultural practices. However, with growing worldwide awareness of the need for responsible practices in aquaculture, governments and aquaculturists are increasingly concerned with the effects of the use of chemicals in aquaculture, especially with those which appear likely to be hazardous to man, cultured stock and/or environment. It has been recognized that there is a need to synthesize and disseminate information on the use and management of "aquachemicals", with emphasis on various aquaculture systems and species utilized. In order to address related issues and needs, two expert meetings on "aquachemicals" were held in May 1996 at the Aquaculture Department (AQD) of the Southeast Asian Fisheries Development Center (SEAFDEC) in Tigbauan, Iloilo, Philippines.

The Expert Meeting on the Use of Chemicals in Aquaculture in Asia, held 20-22 May 1996, was organized by SEAFDEC/AQD and the FAO Fishery Resources Division with support from SEAFDEC, FAO and CIDA's ASEAN Canada Fund. WHO headquarters covered the participation of a human health expert. Experts from several institutions and organizations active in the region were invited including the Network of Aquaculture Centres in Asia-Pacific, Fish Health Section of the Asian Fisheries Society, Japan International Research Center for Agricultural Sciences, and others. The meeting was attended by 27 participants and more than 70 observers, from the public and private sector in 20 countries.

Presentations included:

(a) general thematic reviews on a wide range of subjects including:

  • use of chemicals in aquaculture: issues and challenges,
  • antibacterial chemotherapy in aquaculture,
  • ecological effects of chemical usage in aquaculture,
  • transferable drug resistance plasmids in fish-pathogenic bacteria,
  • use of chemicals in aquafeeds,
  • human health aspects of use of chemicals in aquaculture,
  • regulations on use of chemicals in aquaculture,
  • use of organic manures, fertilizers, and soil and water conditioners in aquaculture, and

    (b) country overview papers on the use of aquachemicals in Bangladesh, Cambodia, China, India, Indonesia, Japan, Laos, Malaysia, Pakistan, Singapore, Philippines, Taiwan (Province of China), Thailand and Viet Nam.

    General information on relevant international initiatives and agreements was also presented, including:

    (i) the Code of Conduct for Responsible Fisheries and its Article 9 on Aquaculture Development,

    (ii) the FAO/WHO Codex Alimentarius Commission, its Joint FAO/WHO Food Standards Programme and the Proposed Draft Code of Hygienic Practice for the Products of Aquaculture,

    (iii) the Joint FAO/WHO Expert Committee on Food Additives (JECFA),

    (iv) the Sanitary and Phytosanitary Agreement (Article XX of Legal Texts of the Uruguay Round adopted by Members of the General Agreement on Tariffs and Trade), and

    (v) the International Code of Conduct on the Distribution and Use of Pesticides.

    After the presentations, participants and observers met in working groups and plenary sessions to discuss the roles and responsibilities of both the private sector (manufacturers, suppliers, retailers, users of chemicals) and the public sector (government, line agencies and academia), in relation to the use of aquachemicals and possible avenues for improved collaboration among all parties concerned.

    General findings from this expert meeting can be outlined as follows:

    (i) A wide range of chemicals are being utilized in aquaculture, for numerous purposes and in different aquaculture systems. When discussing aquachemicals, it is important that clear distinctions be made between the many different aquaculture systems and species employed and the specific patterns of application of chemicals.

    (ii) Many chemicals are essential for successful and efficient farm and hatchery management.

    (iii) Generally, most chemicals used do not appear to carry significant potential for adverse effects on human health or environment, provided that they are applied in a technically appropriate manner.

    (iv) Significant difficulties were experienced in the compilation of data on chemical usage in Asian aquaculture, and further efforts are urgently required to generate an adequate information base for management advice on safe and effective use of chemicals.

    (v) There is a need to facilitate exchange of information and collaboration among manufacturers, suppliers, "middlemen" (salesmen, traders, etc.), importers, and users (i.e. aquafarmers) of chemicals.

    (vi) The roles and responsibilities of the public sector (i.e. government, academia) are significant with regard to management and regulation of chemical usage in aquaculture.

    (vii) There are major constraints to the promotion of safe and effective use of chemicals in aquaculture:

  • lack of trained manpower (e.g. lack of experienced fish health management specialists) and related capacity building schemes and support services to disseminate information on fish health management;
  • the misapplication of some chemicals (e.g. the excessive prophylactic use of antibacterials) is often due to aquafarmers lacking access to information on appropriate use, or due to the lack of effective yet economic viable alternative management measures or suitable alternative chemicals which would help reducing the use of some potentially hazardous chemicals; promotion of certain chemicals by "middlemen" (salesmen, retailers, etc.) or drug companies may also play a significant role in the overuse of chemicals;
  • insufficient understanding of mode of action and efficacy of certain chemicals (e.g. some chemotherapeutants and pesticides), especially under tropical aquaculture conditions;
  • uncertainties with regard to legal and institutional frameworks to govern chemical usage in aquaculture; specific provisions are insufficient or even lacking; mandate and responsibilities of various line agencies in charge of public health and food safety, agriculture, animal health services, environment, etc., sometimes are not well defined; there are enforcement problems.

    (viii) The use of chemicals in aquaculture may have significant implications for international trade of aquaculture products. Countries exporting aquaculture products, especially shrimp, are facing food safety requirements (e.g. maximum residue levels; banning of chemicals) which have been or are being formulated by importing countries. Controversy on these issues may increase due to activities by certain pressure groups.

    This first regional expert meeting on the use of chemicals in Asian aquaculture showed that collaboration among organizations and initiatives active in the region (e.g. SEAFDEC, FAO, CIDA, NACA, Asian Fisheries Society, Asian Institute of Technology, and others) can be very successful. Similar collaborative efforts should be further promoted, with emphasis on increased involvement of representatives of the private sector (pharmaceutical, pesticide and feed manufacturing industry, traders, and aquafarmers).

    The findings of the regional SEAFDEC/FAO/CIDA expert meeting were discussed by an ad hoc meeting (24-28 May 1996) of the GESAMP1 Working Group on Environmental Impacts of Coastal Aquaculture with a view to address major environmental and human health issues related to the use of chemicals in coastal aquaculture as practised worldwide. The experts compared experiences and information available from coastal aquaculture in temperate and tropical environments. They reviewed groups of aquachemicals including antibacterial agents, pesticides, herbicides / algaecides, therapeutants other than antibacterials, feed additives, anaesthetics, hormones, soil and water treatment chemicals, fertilizers, disinfectants, and chemicals associated with structural materials.

    Discussions dealt with issues of concern related to stimulation of resistance, health of employees, residues in seafood, residues in non-cultured organisms, toxicity to non-target species, persistence in aquatic environments and effects on sediment biogeochemistry. The group also examined major problem areas and possible solutions, particularly intensification, fish health management and access to information; residues and related assessment methods and enforcement issues; prophylactic use of antibacterials; quality assurance of chemicals used in aquaculture; lack of data on quantities of chemicals used; difficulties of effluent treatment; international trade; lack of information specific to the environment; lack of alternatives; and lack of regulatory controls. A set of guidelines for use of chemotherapeutants and pesticides in coastal aquaculture was formulated.

    The proceedings of the regional SEAFDEC/FAO/CIDA expert meeting as well as the study report of the GESAMP Working Group are currently under preparation and are expected to be published in 1997. (GESAMP = IMO/FAO/Unesco-IOC/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on Scientific Aspects of Marine Environmental Protection).

    Contacts for further information:

    Mr Uwe Barg
    Fishery Resources Division
    Food and Agriculture Organization
    of the United Nations (FAO)
    00100 Rome, Italy
    Tel: ++39-6-570-53454
    Fax: ++39-6-570-53020

    Ms Celia R. Lavilla-Pitogo
    Southeast Asian Fisheries
    Development Center (SEAFDEC)
    Aquaculture Department
    5021 Tigbauan, Iloilo, The Philippines
    Tel: ++6333- 3351009
    Fax: ++ 6333- 3351008