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Icthyology Exam #3 (Homeostasis [Osmoregulation]: H2O loss or gain ,…

- - - - Urea in blood nearly isosmotic with seawater
  - - - Blood basic --> less breathing
      - Blood acidic --> breathe (H2CO3)
    - - CO2 levels similar to water
      - CO2 levels in water variable (temperature)
      - So can't rely on breathing to regulate CO2
      - Use epithelial transport of H+ and HCO3-
      - Chloride cells (ionocytes)
        
        Exchange H+ and HCO3- for Na+ and Cl -
        
        Need to buffer the H+ ions in solution
    - - Increase in [H+] , Excessive Na+ losses
        
        High environmental [H+] inhibits H+ excretion and Na+ intake, Fish die from low plasma NaCl
  - - - Health, growth, reproduction
        
        egg survival
        
        Embryonic development
        
        sperm motility
        
        Larval mortality and decrease larval growth
        
        Sexual maturation
      - Population structure
    - - PCB
        
        Atlantic croaker --> smaller ovaries
        
        White sucker --> no increase in fecundity with age
      - Endocrine disruptors
        
        Pulp mill effluent
        
        Precocious development in adult traits in American eels
        
        Masculination
        
        Chemical masculination of secondary sex characteristics. (A) the anterior rays of the anal fin of a male mosquitofish (Gambusia affinis) are elongated to form the gonopodium, which is used to inseminate females. (B) the anal fin of the female mosquitofish does not have a gonopodium. (C) however, females can become masculinized by exposure to pulp-mill effluent and develop a gonopodium
        
        Gonopodium
        
        Female has an 81% increased interest for large gonopodium male than the small gonopodium male
        
        But: Large gonopodium --> resulted in slower fish
        
        5 more items...
        
        Maturity in white sucker and lake whitefish
    - - Biomarkers - detect subcellular/cellular levels before organismal and population impacts
        
        Subcellular
        
        Metallothioneins (heavy metals)
        
        Cytochrome enzymes (PAH, PCB)
        
        increased liver enzymes (organic chemicals)
        
        DNA alteration
        
        Cellular/tissue
        
        Liver tumors (contaminated sediments)
        
        Repercussions as liver affects energy storage/metabolism
        
        Gills (gas exchange, excretion, ,osmoregulation, acid-base balance)
        
        Acids, Metals, Detergents
        
        Mucus production
        
        Thickening of gill epithelium
        
        Gill hemorrhaging
        
        Spleen (immune system)
        
        Higher macrophage aggregates- white blood cells that phagocytize and digest foreign cells and cellular debris
        
        Allow for early detection of stressors (physiological, growth, reproductive success, & community structure
    - - Increased gill permeability and Hydromineral imbalances
    - - Loss of water and gain in ions in marine fish
      - Gain of water and loss of ions in freshwater fish (can add salt in transport tanks)
  - - - Can have high O2 but due to respiration have high CO2
    - - Freshwater - Chloride cells (ionocytes) exchange H+ and HCO3- for Na+ and Cl- ; on gill filaments, skin inside operculum
    - - Lower growth rates (white sturgeon)
      - Nephrocalcinosis (rainbow trout)
        
        White to gray streaks and spots on the kidney; swelling of kidneys
        
        Can be caused by mineral balance --> magnesium deficient, high calcium; high ratio of calcium or phosphorus to magnesium; high selenium; high cadmium and calcium: and excess phosphorus
        
        Basically--> an imbalance of dietary calcium , phosphorus ,and a diet with 1:1:0:1 calcium to phosphorus to magnesium is suggested
  - - - NH3 -> toxic to fish
        
        small amounts result in stress and gill damage (0.05mg/l) [2mg/l death]
        
        increase susceptibility to bacterial infection
        
        poor growth
        
        Fish do not tolerate handling
      - Measurement
        
        Usually measure (TAN) = NH3+ NH4+
        
        Calculate NH3 from temperature and pH
- - - - Irregularly shaped with branched processes
      - Different [ ]'s at different location of cells provide color change
      - Mainly in dermis (scales, fins, eyes)
      - Hue changes with overlaying of different chromatophores
      - Internal changes of chromatophore with different pigments
  - - - Melanins: dark red, brown, black (background coloration)
      - Purines (guanines): colorless crystalline, silvery sheen of pelagic fish, and iridescent colors
      - Carotenoid: Red, Yellow, and Blue
    - - Territorial Ownership
      - Keep forging individuals in contact with each other
      - Sex and Courtship
      - Predator avoidance
        
        Colors hard to see at low light
        
        Flash effect (side to narrow profile)
        
        Reef colorful so can hide
        
        Aposematic coloring
    - - Flicker fusion (Vertical bands)
      - Matching background color (Flounder, Sculpins, Darters, Blennies)
- - - - Increase in organ size - liver and heart
      - Muscles
        
        may use more muscle cells to swim
        
        Maximum sustainable swimming velocities lower in colder temperatures
        
        more mitochondria in muscles
      - Cell membrane changes (saturated versus unsaturated - butter and vegetable oil)
  - - - Heat shock proteins- reconfigure proteins denatured at high temperatures
    - - Rainbow trout at different temperatures (2 degrees C versus 18 degrees C) have different acetylcholinesterase
    - - Two allozymes of lactate dehydrogenase
      - Maine fish has allele that works in cold temperature
      - Frequency of decreases towards Florida
  - - - Supercooling - but need to touch ice crystals
    - - Ions and solutes depress freezing point of intracellular fluid to ~ -0.7 degrees C
    - - Rainbow smelt produce glycerol as well
      - sweeter in winter
    - - Osmotic stress (solute concentration
    - - Denaturation
      - slows reaction down
  - - - Shut down
      - Pumping
      - Cool hypolimnetic waters attract fish --> increased fishing and stock depletion
    - - Supersaturation of gasses in blood
        
        Gills highly permeable
      - problems when fish move to warmer less turbulent waters
    - - Striped bass (young ~25 C, Old ~20 C)
        
        Thermal preferences affects where "trophy" fish are located
        
        Hypolimnic waters and hypoxia or anoxia
    - - San Fransico Bay Striped Bass
        
        They grow slower and smaller than offspring of hatchery fish raised in clean water
        
        POD (Pelagic organism decline)
        
        decline in estuary populations of striped bass, delta smelt, longfin smelt and threadfin shad
        
        Underdeveloped brains, inadequate energy supplies and dysfunctional livers
        
        Chemicals
        
        PCB's (polychlorinated biphenyls)
        
        Pesticides- chlorpyrifos and dieldren, and DDT
        
        PBDE's (polybrominated diphenyl ethers) - flame retardants
    - - Metabolism- digestion affected
      - Bear Lake Sculpin (Cottus extensus)
        
        Bottom feed 5 degrees C
        
        digest on surface (13-16 degrees C)
        
        Digestion 3%/hour --> 22%/hour
        
        growth increases 300% from on 5 degrees C
    - - Food
      - Predators
      - DO
      - Competitors
      - Temperature - is a strong determinant
    - - Metabolism- digestion affected
      - Sockeye Salmon (Oncorhynchus nerka)
        
        Digest in warm area (15 degree C at 11 m) after feeding
        
        During day go to cold (5 degree C at 37 m) to conserve energy
- - - - Extremely sensitive to AC and DC
      - Respond to own movements through Earth's magnetic field- navigation
      - Get induced electrical currents (2cm/s)
    - - So background rate of nerve impulse
      - detection of any disruption
      - Respond to electrical discharge of own organs (EOD's) Electrical Organ Discharge
- - - - Moves endolymph
        
        Moves cilia (cupula)
        
        Sensory Neurons Fire
      - Otolith: earstone rests on a bed of sensory hairs
        
        provides information on vertical orientation, works with eyes- dorsal light reaction (remove otolith and fish keeps dorsal surface to light even if light is from side)
      - Hearing: High frequencies need more energy
        
        Gas in swim bladder has acoustical properties
        
        Gas pulsates and vibrates surrounding tissue> Inner ear
        
        Density
        
        Mean density of fish flesh is 1.075g/ml
        
        Seawater : 1.026g/ml
        
        Freshwater: 1.000g/ml
    - - Mechanoreceptors- similar to auditory + equilibrium called neuromasts
      - Cupulae sensitve to disturbance- displacement
      - Placement: more for pectoral fins or for where expect prey/predator
      - Specializations
        
        Antarctic fish: Tuned to frequencies of planktonic prey
        
        Surface fish: surface ripples from struggling insects (on dorsal surface of head)
        
        Blind cavefish: Neuromasts as ridges on head; very precise prey capture
        
        Deep sea Gulper eel: group at end of stalk- lightless detection of prey
      - Neuromasts: type of radar
        
        Head Neuromasts detect water rebounding from objects
        
        Blind cavefish; aquarium walls
        
        Forward movement displaces water
        
        Schooling behavior continued in Pollock when blindfold but not when lateral line was cut (no schooling)
      - Vision
        
        Eyes similar to other vertebrates
        
        stick out so can see laterally and almost behind
        
        Focus by moving lens (we change curvature)
        
        Tapetum lucidum> (at choroid) reflective guanine crystals
        
        Helps with lowlight (Elasmobranchs, Sturgeons, Some Teleosts)
        
        Rods (low light)
        
        Cones 4 types (red,green, blue, UV)
        
        FW trout 455/530/625
        
        Unusual eye morphologies
        
        Mudskippers- aerial vision
        
        Elasmobranchs- dialate/constrict pupil of eye- pinhole to horizontal slit
        
        Nicitating membrane (semi-opaque eyelid); protection more than light reduction
        
        Deep sea fishes- elongate tubular eyes enhances light gathering and binocular vision