Fish Health

1. Fish Health

2. Fish Health • 2006 NASS US Trout Production • 27.81 million trout lost • Disease Classification • Noninfectious, infectious • Noninfectious • Caused by environmental problems with which the fish cannot cope • Infectious • Microbial pathogens: viruses, bacteria, fungi, protozoa, and metozoa (-todes) • Infectious usually preceded by noninfectious

3. A healthy fish • Behavior • Color • Fins • Skin • Gills • Internal organs

6. In the real world • Common pathogens may be in your system. • For all practical purposes a “disease free” population, especially in a open system, is a myth. Pathogens can be present but may not be expressed.

7. Certification • A population is tested for specific pathogens. • A number of fish are taken so there is 95% confidence that the population sampled is free of specific pathogens. • Lot certification vs. facility certification. • Facility certification is not valid if animals are brought into the facility from another source after certification has been obtained. • Currently no certification system in place for WV growers, but there is progress within WV DAg.

8. Biosecurity • Facility Design • Origin of your fish • Minimize potential for transmission • Predators • Hauling tanks • Dipnets • Boots – Footbath. • Anything else you can think of.

9. How are fish placed at risk for disease?

10. Ways to place your fish at risk • Purchase unhealthy fish • Physical damage • Handling Stress • Transportation • Harvest • High Density • Do nothing to limit transmission of the disease from one group of fish to another.

11. Ways to place your fish at risk • Nutrition and feeding • Poor quality feed • Not enough feed • Pellets too large or too small • Poor Feed distribution • Environmental Factors • Temperature • Water Quality • Turbidity • Solid Waste • Oxygen • Ammonia • Nitrite

12. Predisposing factors • Bacterial gill disease – Crowding, unfavorable environmental condition, and presence of causative bacteria, elevated ammonia, particulate material in water. • Columnaris – Crowding, handling, seining, adverse temperature, other infectious diseases. • Furunculosis – low oxygen, handling when A. salmonicida is endemic.

13. Fish Disease? • Signs there may be a problem • Loss of appetite • Poor Feed Conversion • Change in behavior • Lethargic • Gathering at head or tail of raceways • Flashing • Visible soars or lesions • Dead Fish

14. Identifying the problem • Always look for signs of disease • Monitor water quality • Learn about the patterns for particular fish diseases. • When a problem is evident, act quickly ! • Examine the fish, WQ, history of the system. • Consult with other fish folks. A digital photograph may help. • Send a live sample to diagnostic lab.

15. Response to Disease signs • Stop feeding • Change water/ improve water quality • Remove organic matter • Add Salt • Do nothing • Reduce density • Change environment • Expose to chemical treatment • Antibiotics in the feed

16. Infectious • Viral • IPN • Infectious Pancreatic Necrosis • Young trout • Vertically transmitted to egg • IHN • Infectious Hematopoietic Necrosis • Rainbow trout • VHS • Viral Hemorrhagic Septicemia

17. Infectious • Bacterial • Bacterial Gill Disease • Most common disease of cultured trout • Stress mediated (EGD) • Columnaris • Usually external infection • Furunculosis • Aeromonas salmonicida

18. Infectious • Protozoan “Parasites” • External • Ichthyophthirius multifiliis • “Ich” • Internal • Myxosoma cerebralis • “Whirling disease” • Common signs • “Jumping”, “Flashing”, “Darting”

19. Some common treatments • Salt (Nitrites, stress, external parasites) • 0.1 to 0.2 % indefinite • 1 to 3% as a bath • Paracide F (Formalin) • 24 hour 25 mg/l drip, introduce at 30 ppm. • Hydrogen Peroxide - • Copper Sulfate – for filamentous algae and parasite, • depends on water softness, Trout and Koi are sensitive to this treatment. • Potassium Permanganate – “Oxidizing agent”

20. Treatments • Control/Prevention • Vaccination • Treatment • Antibiotics • Tetracycline * • Romet • Florfenicol (Aquaflor)

22. Disinfection - IPN • Clean the surface (pressure wash) • Scrub with detergents (e.g. simple green) to break up organic • Chlorine 200 ppm • Able to neutralize Chlorine with sodium thiosulfate • 7 mg for each mg of chlorine

23. Laboratory Diagnosis • Most accurate way to determine cause of infection • Call first • Select and pack fish according to recommendations • Fish Diagnostic Labs • State Veterinary Lab – Guthrie Center, WV • Brenda Keavey 558-2214 ext. 4570 • Micro Technologies, Maine • (207) 737-2637

24. Preparing for Disease • Keep common chemicals and drugs used to treat diseases on hand • Select a lab for disease testing • Contact information • Sampling and shipping guidelines • Shipping and transport containers • It is not a question of IFyou will have a disease problem but WHEN • Keep good production records • Many diseases reoccur at certain times or under certain conditions

25. Some Sources of Information • GUIDE TO DRUG, VACCINE, AND PESTICIDE USE IN AQUACULTURE • http://aquanic.org/jsa/wgqaap/drugguide/drugguide.htm • Fish Hatchery Management edited by Gary Wedemeyer. • Diseases of Warmwater Fish and Trout Diseases (DVD). Kentucky State University. • A Manual for Rainbow Trout Production on the Family-Owned Farm by George Klontz • Health Maintenance of Cultured Fishes by John Plumb. • Fact sheets – www.aquanic.org

26. Questions?? Comments