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United States Department of Agriculture

Agricultural Research Service

Therapeutics Evaluation and Registration Research
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Evaluation of Compounds and Strategies for Controlling Aquatic Animal Disease





David L. Straus, Aquatic Toxicologist, Lead Scientist


Bradley Farmer, Support Scientist






Cindy Ledbetter, Biological Science Technician






Objective 1: Develop data needed to demonstrate safety (animal, human, and environmental) and efficacy of compounds that are relevant to the needs of aquaculture. Technical sections will be completed to gain FDA-approval of copper sulfate and potassium permanganate to control mortality associated with Ichthyophthiriasis on channel catfish in earthen ponds. Technical sections for efficacy and target animal safety will be completed for florfenicol. The efficacy of florfenicol and Diquat ? for controlling mortality associated with Flavobacterium columnare will be investigated.


Objective 2: Determine the efficacy of compounds, biological control strategies, clearance rate and pathogenesis (understanding of the disease process) of parasites and fungi applicable to catfish, baitfish, and Morone sp. culture. Snail-eating fish and chemicals will be used to manage trematode infestations. Chemical treatment strategies will be defined to manage the Asian tapeworm on grass carp and golden shiners, the anchor parasite and fish louse on goldfish, and fungus on channel catfish eggs.





 Description of Problem to be Solved


Aquaculture has been a rapidly growing source of food production over the last few decades; total production value in the United States for 2000 was $973 million, of which total finfish production was $714 million. Fish pathogens continue to inflict significant economic losses to the U.S. aquaculture industry; extension personnel estimate that 10% of production ($71.4 million) is lost to parasites and infectious diseases. Current knowledge is inadequate for devising comprehensive management strategies for disease control. Many of the infectious diseases in fish (bacterial, fungal and parasitic) do not have effective vaccines; therefore, the need for safe and effective control measures to minimize losses due to outbreaks is pressing and critical.

Available FDA-approved therapeutants are very limited, and the industry is frequently faced with disease epizootics and no effective measures to curb losses. There is currently one parasiticide and three antibiotics (one is no longer manufactured) approved for use in U.S. aquaculture, with each therapeutant having a specific use. This is an inadequate arsenal against the plethora of diseases inflicting losses to the aquaculture industry. Approval of therapeutic compounds requires comprehensive studies to demonstrate human food safety, animal safety, environmental safety, and efficacy. The HarryK.DupreeStuttgartNationalAquacultureResearchCenter (HKD-SNARC) is uniquely positioned in the aquaculture industry to provide expertise for the evaluation of therapeutic compounds and biological control strategies to improve aquatic animal health.

The development of effective strategies to control fish health problems is also hampered by the limited understanding of the biology, vectors, and epidemiology of fish pathogens plaguing the aquaculture industry. The need for disease control methods (chemical, biological, or environmental) not targeted at the pathogen, but at the intermediate host of these pathogens, is also immediate and critical.


Potential Benefits Expected from Attaining Objectives


Attaining these objectives will provide benefits to farmers, fish health providers, scientists, and the public which will result in increased economic growth by helping to overcome the impact of disease. Environmentally friendly, effective, and food-safe medicines to treat aquatic animal diseases and non-chemical methods to control diseases and disease vectors will become available not only to large commercial producers, but also to small, rural fish farmers. Research will provide the U.S. fish industry with the ability to identify important fish-pathogen hosts so the workforce can limit access of these hosts to ponds.


Anticipated Products of the Research


Additional fish health management strategies for fish diseases (bacteria and parasites) including FDA-approved compounds and the development of chemical and biological control methods to eliminate or reduce populations of non-fish hosts.


Customers of the Research and Their Involvement


Fish farmers of cultured hybrid striped bass, catfish, tilapia, and baitfish species will benefit. Scientists will benefit from the basic knowledge of efficacy and safety of fisheries chemicals used for therapy and vector reduction and the use of biological controls. Fisheries extension agents and veterinarians will have more disease control methodologies available for recommendation to their user groups. Consumers demanding safe and wholesome fish products will benefit.

Last Modified: 8/13/2016
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