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

4
(No Transcript)
5
(No Transcript)
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)

21
(No Transcript)
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
• [phone]

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 IF you 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