Term
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Definition
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Term
Fish Diseases
Three Classes |
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Definition
1) Nutritional - vitamin deficiency, spoiled food
2)Environmental - poor water quality
3) Pathogens or Parasites |
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Term
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Definition
Epidemic (outbreak) in an animal population (not man).
Result of an interaction with:
Fish
Environment
Pathogen |
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Term
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Definition
Fish
-what is the physiological state of the fish (stress?)
- stress - an adverse effect on a fish
- physiological stress response - organisms response to stress
Environment
-does it cause a stress response?
-a response at low temperature is different from one at high temp so environment can affect the magnitude of the response
Pathogen
- all animal pop.'s harbor disease organisms. Can be obligate(must parasitize durin life cycle) or facultative (not required to parasitize but are in fish environment)
-with stress and the correct environmnet conditions pathogens gain a foot hold and fish succumb to the disease |
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Term
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Definition
| some fish are always stressed. However if a stressor is applied additional individuals are stressed and this becomes the breeding ground for disease |
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Term
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Definition
- any change in environmnet since fish metabolism if geared towards existing conditions.
-any factor outside the fish's range of tolerance.
DO too low anoxia too high gas embolism
Unionized amonia- too high problems
Psychological/Sociological Factors
netting fish, holding at high densities |
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Term
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Definition
Primary - release of chemical messengers from brain and hypothalmus
Secondary- decreased white blood cell counts, decreased muscle protein, immunosuppression, decreased liver glycogen, electrolyte changes, increased blood glucose, increased blood lactate, increased heart rate, change in osmoregulation, blanching
Over long term these can be detrimental. |
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Term
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Definition
- Avoid excessive handling
-Use anesthetic prior to handling (salt, low temp)
-Maintain low densities and do not over crowd
-Maintain good water quality
- Keep Fed
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Term
Fish Diseases
natural mortality |
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Definition
natural mortality in fish due to old age is well known, but rare because of other mortality factors(angling, parasite, disease).
However, when holding fish at high densities it becomes more common
In fish culture, most mortalities are due to poor water quality or diseases.
Diseases include viruses, bacteria, fungi, protozoans, acanthocephalans, trematodes, nematodes, cestodes and copepods.
These problems usually follow stress.
Most fish are always carrying diseases which may or may not effect fish. Stress triggers problems. |
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Term
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Definition
often used to treat fish diseases. A few are registered by FDA for legal use.
Calculating treatment dose is critical, often too small.
Sick fish - immune responses, inflammatory responses |
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