Exam 2 Flashcards
hypotonic
less solutes outside of cell
isotonic
same concentration of solutes
hypertonic
more solutes outside of cell
osmosis
diffusion of water across a semipermeable membrane
osmoregulation
a homeostatic mechanism for maintaining solute concentration of body fluids
main osmoregulatory organs of fish
kidney and gills
how do fish control desiccation (loss of water/hydration)
large surface area in contact with water (gills/skin)
freshwater fish tend to ___ water and ___ salts
gain, lose
marine fish tend to __ water and __ salts
lose, gain
what kind of fish is an osmoconformer
hagfish
what kind of fish has a slightly higher osmolality than the environment
elasmobranchs (sharks/skates/rays)
what type of fish live in a wide range of osmotic conditions
euryhaline fish
what kind of fish live in both fresh and marine water
diadromous
what kind of fish spawn in freshwater, but grow and mature in marine water
anadromous (salmon, sea lamprey)
what kind of fish spawn in marine water, but grow and mature in fresh water
catadromous (anguillid eels)
freshwater teleost have __ urine
watery
ectothermy
relying on external heat sources
endothermy
relying on internal heat sources
homeothermy
body temperature held at a constant level
poikilothermy
body temperature varies with environmental temperatures
heterothermy
partial or regional endothermy
consequences of lower body temperature in fish
decreased metabolic rate and changes to membranes
how do fish adapt to cold temperatures
increase concentration of key metabolic enzymes, increase proportion of unsaturated lipids, decrease cholesterol
how do fish deal with freezing
they produce antifreeze compounds and higher amounts of some solutes to depress the freezing point of intracellular fluid
fish that can thermoregulate through eyes
swordfish, marlin, lamnid shark
mechanoreception
the detection of pressure waves in water
what does the lateral line of a fish do
measure water movement/pressure change
modifications in fish to increase hearing
gas filled extensions of swim bladder
electroreception
passive- detection of externally generated electric fields
active- fish generate own electric signal and detect disturbances
types of receptors in fish
tuberous and ampullary
what effect does electric discharge have on fish
species recognition, sex recognition and courtship, dominance and social rank
turbidity
cloudiness of water
measure of Ca and Mg
hardness
measure of NaCl
salinity
what effect does pH have on fish
effects transport mechanisms in fish gill membranes
a measurement of how much acid can be neutralized by water
alkalinity
toxic to fish
ammonia and nitrites
open water system
water in enclosure replaced on a continuous basis
closed water system
water recirculates within
keys to successful fish raising
water quality, quarantine and prophylactic treatment, diet
3 main problems with water quality
- organic/nutrient load problems
- exacerbation of pathogen life cycle
- overcrowding and stress
top water quality problems
new tank syndrome, high organic load, acidification
new tank syndrome
build up of toxic nitrogen compounds (ammonia and nitrites)
heterotrophic bacteria
uneaten food, fish feces
aerobic and autotrophic
ammonia and nitrite oxidizers
two important factors of filtration
surface area and flow
sources of high organic load
overfeeding and lots of decaying plant/animal tissue
what problems does a high organic load cause
increase in nutrients for algae, increase in heterotrophic bacteria
accumulation of acidic compounds normal in healthy tank
acidification
what causes low pH
tanks with poor buffering capacity or good buffering capacity (no reduction of pH until buffer is used up)
problems of low pH
stress, damage to epithelial tissues, disruption of ion balance, toxicity of certain metals
