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U.S. Department of Health and Human Services

Animal & Veterinary

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by Charles E. Eirkson III
FDA Veterinarian Newsletter May/June 1998 Volume XIII, No III

Following is a summary of the International Harmonization of Aquaculture Drugs and Biologics and World Aquaculture Meetings, held February 15 - 19, 1998, in Las Vegas, Nevada.

Aquaculture International Harmonization Meeting

During the Aquaculture International Harmonization Meeting there were presentations by individuals representing or relaying their interpretations of various international organizations including the Food and Agriculture Organization of the United Nations (FAO), World Health Organization (WHO), Office International Des Epizooties (OIE), CVM, Organization for Economic Co-operation and Development (OECD), USDA, European Union (EU) and private industry. Dr. Albert Tacon of FAO presented information on the total aquaculture production, estimated at 28 million metric tons and 43 billion U.S. dollars annually. Ninety percent of the total is from Asia, consisting predominantly of lower-value herbivorous fish for mass market, while the developed countries produce higher value carnivorous species for selected markets. It was pointed out that the higher-value markets consume 450 Kg fish meal and 250 mg fish oil to produce 1 metric ton of fish (salmon). Dr. Michael Blackwell from CVM presented information on international efforts under CODEX Alimentarius Commission, Veterinary International Cooperation on Harmonization (VICH) and North American Free Trade Agreement (NAFTA). He also provided a summary of CVM's efforts under the minor use minor species (MUMS) policy to provide for approvals of drugs for aquaculture. Dr. Gudrum Gallhoff from the EU discussed the EU process for registration. There is a centralized process for approval at the EU level and a decentralized process for approval within member countries. At the decentralized level, MRL is still determined at the centralized level to provide for trade between EU countries. Additionally, all biotechnology products must go through the centralized process and all aquaculture products are required to go through a phase II ecotoxicity review. Dr. Alan Reilly from WHO discussed concerns about antibiotic resistance associated with aquaculture. He stressed that human medicine was the largest contributor but that there is a potential for problems from resistance development and transfer in aquaculture, especially in the tropical zones. He noted that some data (unspecified) demonstrates that resistance development from aquaculture in temperate zones is low. Dr. Rolf Nordmo of Vikan Research, Norway, discussed the GLP OECD/GD (92) process.

Dr. Michael Blackwell presented an in-depth discussion of VICH and its process. Dr. Raphaela le Gauvello of Stermor Aquaculture Health Consulting, France, discussed the EU requirements for aquaculture under the current ecotoxicity and food safety requirements. All aquaculture is currently phase II which requires environmental testing. She also expressed and confirmed that residue markers established for other species are now accepted for aquatic species. Dr. Mark Wood of the Animal Health Institute presented the U.S. animal health industry perspective of aquaculture markets by expressing that the cost of drug development is still not balanced by the available aquaculture market making development prohibitive. Dr. J. Brackett of Syndel Laboratories, Canada, expressed that there is a need for harmonization to reduce cost and that risk assessment should be the preferred approach in dealing with drug approval. Risk assessment could be used to identify low-risk uses and reduce regulatory requirements for those uses. Dr. Blackwell of CVM presented more details concerning CVM's MUMS proposal, specifically, the removal of disincentives for drug development, including improving enforcement for unapproved products, changes in standards for approval and assuring that existing approvals will not be jeopardized by minor use supplements.

Reports for the Education-Communication, Prioritization, Research, and Level Playing Field Committees were presented. The Education-Communication Committee reported that a web cite at aquaintharm-mg@usda was developed. The Prioritization Committee noted that there are approximately 27 products approved in Japan, 9 in Europe, 4 in Canada and 2 in the U.S. The Research Committee identified a lack of knowledge of basic fish anatomy and physiology. The Level Playing Field Committee reported that its membership had fallen and there is a need for producers and manufacturers to get involved. There is a critical need to cover areas of drug and biologic availability, open markets, and investment.

World Aquaculture Meeting

On Monday February 16, there were sessions on Aquaculture Engineering Society Fundamental Workshop, Aquaculture Drug Approvals Through Producer INADs, Biosecurity Measures that Reduce Risk for Aquatic Species in the Aquatic Animal Health and Clarifying the Department of Commerce's Role in the Development of U.S. Aquaculture. During the Engineering session, it became apparent that there is a critical need for separating and disposing of solids from recirculating systems. These solids require subsequent disposal and can present environmental issues. Data were also presented that biofilters are critical for proper control of nitrate and nitrite levels and that these systems can be damaged or destroyed with the presence of antibiotics in effluents. During the INAD session, the presentation on the Development of Data for Approval of Cypermethrin to Control Freshwater External Parasites was replaced with a presentation on a new (unidentified) fungicide and antimicrobial to be submitted for consideration at FDA by Grampian Pharmaceuticals. It is claimed that the product is a replacement for malachite green. During the session on Biosecurity Measures, the need to prevent microbial and viral contamination of aquaculture sites following formats used in the poultry industry was presented. The emphasis was on the prevention of disease to provide for successful aquaculture development. The session on Clarifying the Department of Commerce's Role in the Development of U.S. Aquaculture provided a public forum to facilitate communication on a new Department of Commerce strategic plan for supporting aquaculture through the year 2005. The plan stimulated a prolonged discussion with the representatives of the aquaculture industry. Apparently there is considerable difficulty between USDA and Commerce and within Commerce in promoting and supporting aquaculture in the U.S. The Department of Commerce has the difficult task of balancing the regulation and promotion of commercial fishing and aquaculture in a marine environment.

On Tuesday, February 17, during a session on the Environmental Impact of Shellfish Aquaculture, topics on environmental damage from collecting mollusk spats (larval stage) and the transmission of pathogens were covered. The collection of spats for transplant to culture operations reduces the wildstock populations; in some areas to the point of removing the necessary food-base for a number of predatory birds that feed on mollusks. The populations of the birds are reduced. Data were also presented on the transmission of Campylobacter spp. from mollusk culture facilities to nearby beaches. Apparently, birds which land on mollusk facilities pick up, on their feet, Campylobacter, and other pathogens and transport them to other areas. They have measured higher than expected pathogen numbers at public facilities where birds congregate. A session on Aquaculture Pond Soil Quality Management stressed the need for active and balanced microbial populations in the pond soil to maintain proper pond chemistry. The management of acidity, sulfate, and other biological and chemical factors are modulated by microorganisms in pond sediments. The removal of microbes could adversely affect sustainable production in ponds. The session titled "Aquaculture Drug Approval Process - A Success Story," indicated that drug approval provided a positive perspective of CVM's efforts at promoting the investigation and approval of drugs for use in aquaculture. It provided a good deal of information on the U.S. Fish and Wildlife Service experience in conducting investigations on a number of new animal drugs.

On Wednesday, February 18, sessions included a Forum on Sustainability, Shrimp Ecosystem Stability and General Contributed Papers. During the first two sessions, there was considerable discussion of the modification of lands for use in shrimp farming. Many terrestrial agricultural (rice) and forested (mangrove) ecosystems have been converted to shrimp production without planning and, subsequently, abandoned. The removal of previously productive rice plantations has caused adverse social, ecological and economic impacts in some areas. The removal of mangrove forests has also caused ecological and economic impacts in some areas. There are also cases where there are significant increases in economic and social benefits from shrimp farmers. The session focused on the need for better planning and, perhaps, regulation to control the siting of shrimp farms. During the session on General Contributed Papers, a talk entitled the "Effects of Tetracycline Use in Aquaculture on Microbial Communities" provided data on the use of chlortetracycline and tetracycline and the subsequent development of drug resistance in fresh and marine systems. For freshwater uses, drug resistant organisms were observed in effluent and sediment from the aquaculture facilities in California. The amount of resistance formation appeared to be correlated with the concentration and sorption of tetracycline. In a marine system, the amount of resistance could not be correlated with the concentration or sorption of tetracycline. There were higher levels of resistance than expected. It appears that the development of resistance from selective pressure in a marine system is different from a fresh water system.

On Thursday, February 19, a session on Shrimp Pond Ecosystem Stability discussed the need for settling basins or wetlands to treat effluents from shrimp ponds. Nutrient and suspended solids loads are high and settling basin or wetlands are needed to reduce loads entering into marine and freshwater systems. There was also a presentation on conducting an environmental assessment for siting a shrimp farm and on the restoration of shrimp ponds. T

he meeting provided attendees with valuable insight into the potential environmental impacts of aquaculture. It was recognized throughout the meeting that microbial communities are critical for maintaining the sustainability of aquaculture facilities and that these communities, and the benefits they provide, can be disrupted by the use of antimicrobial agents. In addition, drug use in aquaculture represents a hazard to ecosystems receiving effluents from aquaculture facilities. The development of antimicrobial resistance was also associated with the use of antibiotics in aquaculture facilities. Considerable evidence supports a need to adequately study the potential effects of aquaculture drug products on fresh, estuarine and marine ecosystems but also confirms that significant benefits are derived from the use of these products.