Fishes - the teleosts Flashcards
What is order Clupeiforms?
Herring, anchovy
What is order Salmoniformes?
salmon, trout, smelt, pike
Order Perciformes
perch, sandlance, tuna
Order Scorpaeniformes
rockfish,lingcod, sculpin
Order Pleuronectiformes
flounder, sole, halibut
How do fishes acheive neutral buoyancy?
Some ray-finned fish use oils, have a cartilagenous skeleton or reduced skeleton or muscular tissue, most have a swim bladder
What is a swim bladder?
A modified lung, lungs developed as outpouchings of the gut likely in tropical freshwater where ability to breathe are would be advantageous
What are 2 fish that don’t have swim bladders?
mackerel, angler fish, lophius, uranoscophus
How do fishes achieve neutral bouyancy?
2 types of swim bladders
1) connected to gut
2) closed
What is a connected swim bladder?
connected to gut via pneumatic duct , gas exchange via esophagus
inflate by gulping air
deflate by gas-spitting
herring, salmonoids, pikes catfishes, eels
What is a closed swim bladder?
closed to gut, gas exchange via circulatory system
inflate with gas gland and capillary system
deflate by diffusion of gases through the oval (patch of dense capillaries) into the blood
- most teleosts
Functions of a swim bladder
buoyant to float
sound producer and receptor
respiratory organ
Are most fish ecto or endothermic?
ectothermic with temps close to ambient b/c heat is rapidly lost through skin and gills
What methods do fish use to thermoregulate?
behaviorally, physiologically, or both
Describe an example of behavioral thermoregulation
salmon digest food after dusk feeding in a warmer temperature selectively
daytime they conserve energy by moving to colder water
Describe physiological (metabolic) thermoregulation
based on oxidation of food
only in continuously swimming fishes (tuna, mackerels)
warm red muscles can contract faster than cold white muscles…..
heat loss to environment is limited by counter-current heat exchange of the blood btwn the muscles and gills
body temperatures of warm-bodied fishes are not constant but fluctuate with ambient temp.
Describe structure and function of fish gills
water flows in mouth and over gill arches, through gill filaments, and out gill flaps
Describe counter-current exchange
oxygenated water flows over lamellae where deoxygenated blood flows towards it from the opposite direction
oxygenation is higher closest to vessels and poorest closest to veins and vice versa for the blood
What is an osmoconformer?
no osmoregulation
hagfish
Osmoregulation in elasmobranchs is?
Isosmotic
salt concentration 1/3 of seawater but total concentration (urea, TMAO) equal to seawater
Osmoregulation in marine teleosts is?
Hyposmotic to seawater
replace lost water by drinking sea water and excess salt is excreted in concentrated urine (ammonia?) and through gills
Osmoregulation in freshwater teleosts is?
Hyperosmotic to freshwater
excess water excreted in a dilute urine
What is stenohaline
restricted tolerance to changes in environmental saltwater concentration
most fish
What is euryhaline
ability to tolerate wide ranges of saltwater concentrations
move between fresh and marine environments
salmon, lampreys, eels
Olfaction
Imprecise samplin of small quanitities away from source (smell)
- receptors in nares for food detection and finding natal (spawning) stream
Gustation
Precise sampling of large quantities at the source
- Taste buds in mouth and skin, fins, barbels to identify food
Acoustico-lateralis system
hearing
- otoliths in inner ear move against sensory hair cells
lateral line
neuromasts near lateral line canal dectect water movements
- water movements bend the cupula and this triggers hair cells
Chemo rececption relates to?
olfaction and taste
Acoustico lateralis system relates to?
hearing and lateral line
population parameters; population size needs to take what 4 things into account?
births - deaths
immigration - emmigration
Growth is conversion to what?
conversion of calories to somatic and reproductive tissue
What is the growth equation?
I = M +E +G i = ingested food M = energy expended for metabolism E = energy excreted (feces, ammonia, urea) G = energy expended for growth and reproduction
What are 5 factors affecting individual growth?
Age and maturity Temperature Dissolved oxygen levels Competition Food availability
What are 3 measurements of individual growth rate?
Mark-recapture - growth rate = change in size/time period
Length-frequency - rates determined by comparing mean lengths between age classes
Growth rings on hard surfaces - scales (annuli), otoliths - daily increments of growth
Define migration
Regular Mass movements of fish from one place to another (not individual movements)
What are 2 types of fish migration?
Daily - feeding or predator avoidance
Seasonal - migrate long distances in short time spans to specific locations
- tuna, salmon, eels
What is Semelparous?
one reproductive bout in a lifetime
What are 2 reasons fish migrate?
Reproduction - favourable environment, reduce competition for age classes, reduce cannibalism and disease transfer
Changing environments - temp and movements of prey
Why are salmon signatures found in growth rings of trees?
nutrient rich salmon carcasses are moved into the forest by bears that transfer large quantities where the carbon and nitrogen isotopes can be measuredto identify past salmon abundance in trees
How do fish migrate?
odor of parent stream and streams along the way pheromones magnetic field ocean currents and gradients position of sun
