(February 19th Notes)

Coral Reef Fish: Form, Function,Ecology, and Evolution

How much of planet is freshwater?

Less than 2% of the water

How many fish species live in the ocean ?

Around 20,000 salt water fish species

Sharks and Rays

  • Have adaptive immune system

Basic fish anatomy in identifying the fins

Lateral lines – Used to to detect vibrations

  • Banding patterns
    • Strips on fish

Bar (vertical lines)

Stripe ( Horizontal line)

Band (Diagonal lines)

Specialized cells for color and iridescence

  • Chromatophores  
    • Cells that contain pigments
    • Stimulated by nerve impulses and or hormones
    • Higher density of cells
      • More brilliant color
  • Iridophores
    • Cells with crystals that reflect light
    • Act like mirrors (Silvery fishes)
    • Can display different shades of green, blue, pink, and iridescence
  • Hogfish
    • Rass family (dorsal spine)
      • Change color using its cyclic AMP in the skin
  • Camouflage for predators and prey
    • Some fish use Camo as a foraging strategy : sit and wait to eat (ambush predator)
    • Some fish use camo to blend into their surroundings to keep from being eaten.   
  • Colors or patterns can indicate social and sexual status
    • Male (terminal phase)
    • Female (Initial phase)
    • Sequential hermaphrodites
      • (protogynous fish and
  • Courtship, Mating, Egg Guarding
    • Some female fish may be attracted to male fish
  • Getting noticed when you’re drab
    • Making a visual queue to attach fish to mate with.
      • (Just like a bowerbird)
  • ANother use of color is countershading
    • Dark on top and light on bottom to conceal yourself
      • For predators or to sneak on prey
        • Dark on top (dorsal)
        • Light on bottom ( Ventral )
      • Light Ventral surface of a counter blends in with the lighter surface when viewed from below, camouflaging the shark from predators.
  • Other functions of color and patterning
    • Concealed eye
    • Exaggerate size
    • Advertise Toxicity

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