Aquatic Medicine Flashcards
aquatic systems and water quality aquatic diseases
What are the 4 major groups of fish populations that are important in the United States?
- food (ex. atlantic salmon)
- tropical (ex. the cute little fish you see at petco)
- Ornamental/Pond (ex. koi)
- Bait fish (ex. goldfish, minnows)
An OPEN water system has a reliable, suitable water source with excellent water quality.
Why does this system allow for high stocking densities?
Because there is a continuous flow of water coming in and flushing out of the system, therefore metabolic waste does not have the opportunity to build up and cause toxicities to the aquatic population within.
In a __________ water system, there are generally limited stocking densities. There is less total water required for these systems and the water quality is better able to be controlled (most of the time).
closed
For the following system examples, provide the type of system they are – open or closed.
Raceway:
Pond:
Aquarium:
Pens:
Recirculation system
Cage:
Raceway: open
Pond: closed
Aquarium: closed
Pens: open
Recirculation system: closed
Cages: open
What do fish excrete (as waste)?
(4 things)
ammonia
CO2
solid waste
liquid waste
What is the nitrification process?
the aerobic conversion of ammonia (waste produced by fish) into nitrite, followed by the conversion of nitrite into nitrate by bacterial organisms.
Which of the following is MOST toxic to an aquatic species (assume each is within similar ranges)?
a. ammonia
b. nitrite
c. nitrate
b. nitrite
T/F: open systems do not require filtration because dilution is what is creating an appropriate environment without waste.
true
closed systems require some type of filtration in order to convert ammonia to nitrite to nitrate.
What are the top 5 parameters of water quality?
- temp
- dissolved oxygen
- pH
- ammonia
- nitrites and nitrates
Temperature changes affect the metabolism and ______________ of aquatic species. Rapid changes in temperature or temperatures outside of optimal ranges for a specific species will cause stress.
immune response
All of the following are circumstances that would promote what?
- animal and plant respiration
- organic decomposition
- diel cycle (day vs night)
- warm water temperatures
depletion of oxygen
what are the 3 sources of oxygen for aquatic species?
- diffusion
- photosynthesis
- chemical production
Species-specific requirements for dissolved oxygen are approximately 5 ppm minimum.
What signs would be apparent in fish within an environment that has LOW dissolved oxygen?
gulping at the surface
lethargy
increased ventilatory rate
State the acceptable pH range for:
- saltwater fish:
- freshwater fish:
- saltwater fish: 7.8-8.6
- freshwater fish: 6.8-7.8
if ammonia is toxic to fish, then why is the acceptable level of ammonia listed as <0.02 ppm rather than 0 ppm?
these are living animals… something will always be produced by them.
pH and temperature have what influence on ammonia?
increase NH3
salinity, hardness, and CO2 have what influence on ammonia?
decrease NH3
What is ‘new tank syndrome’?
New aquatic systems take at least 6 weeks to overcome excessive ammonia or nitrite levels due to the lack of bacteria available to convert ammonia to nitrite to nitrate.
At first, you are constantly checking the water quality, but after 6 weeks you can better rely on the nitrification process.
How can you measure water salinity in your clinic?
refractometer
measure the specific gravity
T/F: chorine and chloramines are not as toxic to fish because they are present in the waterways on a regular basis.
false – they are toxic to all species of fish and need to be removed by chemicals, aeration, or activated carbon.
Fish and other animals actually have lots of commonalities. What are the 2 biggest differences / adaptations of fish?
- skin – their epithelium is a LIVING layer and they have scales (bony plates) anchored into their dermis to protect themselves.
- gills – respiration, excretion, and osmoregulation (O2 in from water, CO2 and ammonia out, ion exchange and minerals)
T/F: Ejection of scales from the dermis is a normal postmortem change in most aquatic species
false – this indicates damage to the skin/dermis because in order for the scales to come out, they must be pulled from the dermis.
what is the primary site of ammonia secretion for aquatic animals?
gills
T/F: lamellae are so thin that there is almost no energy required for oxygen to go across into the gill filament and for CO2 and ammonia to be excreted out.
true
3 major functions of the gill:
respiration
excretion
osmoregulation
____________ is the process by which a fish adjusts and maintains homeostasis in a changing aquatic environment
osmoregulation
Describe osmoregulation in fresh water fish
fresh water fish have a passive inflow of water into the gills (osmosis) and passive loss of salt from gills (diffusion)
they actively take in salt by the gills, reabsorb salt by kidney (urination), and eliminate large amounts of urine to rid excess water
Describe osmoregulation of salt water fish
they have passive intake of salt through gills (diffusion) and passive loss of water from gills (osmosis)
they actively intake large amounts of water by drinking sea water. the water gets absorbed in the gut, but not the salt. The salt is eliminated actively through the gills. Salt water fish only urinate small amounts in order to conserve their body fluids.
When fish present to your clinic, they are typically presenting with which stress response?
tertiary.
what does the degree of stress and its effect on fish health depend on?
- duration of the stress
- onset of the stress
- absolute degree of the stress
What is the biggest environmental stressor that increases the risk of disease in fish?
poor water quality
What are common clinical signs of disease in fish?
- changed behavior
- decreased appetite
- change in coloration
- dev external lesions
- increased morbidity and mortality