Fish: Osteichthyes

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Fish Osteichthyes

• November 15, 2007

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Osteichthyes

• Skeleton of bone
• Make up 96 of all fish

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Body Shapes
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Fusiform Body Shape
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Laterally Compressed Body Shape
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Flattened Body Shape
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Eel-Like Body Shape
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Irregular Body Shapes
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Fish Coloration

• Where does coloration come from?
• Types of Coloration
• Warning Coloration
• Cryptic Coloration
• Disruptive Coloring
• Countershading

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Locomotion

• Rhythmic side to side motion of body
• Produced by myomers

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Types of Locomotion
Eel-like Cadual Dorsal/anal Pectoral Other
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Adjusting Buoyancy

• Problem Body tissue is denser than water, so
  sinking can be a problem for fish
• 2 solutions
• Swim constantly to overcome gravity
• Become neutrally buoyant

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Neutral Buoyancy

• Swim bladder
• gas-filled sac below
• the spinal column
• Occupies about 5
• of a fishs body volume
• Changing Depths
• Swim bladders than are connected to the gut
• Others must secrete gas from their blood

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Feeding
Capture large prey whole Pickers ingest small
prey whole Grazers Filter Plankton
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Feeding
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Circulatory System
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Respiratory System
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Gills
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Gills

• Countercurrent Exchange

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Regulation of Internal Environment
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Sensory Systems

• Smell/Taste
• Vision
• Lateral Line

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Sensory Systems

• Otoliths

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Regulating Temperature

• Ectotherm gain their heat largely from external
  sources (basking in the sun, etc.)
• Endotherm depend on metabolic production of
  heat to raise their body temperature
• Endothermy very difficult in fish
• Some fish (such as tunas,
• mackerels, swordfishes, etc.) have endothermy

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Behavior

• Schooling
• What are the reasons fish might school?

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Behavior

• Migration

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Sarcopterygii - Lobe-Finned Fishes

• Only 7 living species
• Include the coelacanths
• All tetrapods evolved from the sarcopterygii

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Actinopterygii - Ray-finned Fishes

• Include almost all modern fish
• About 24,000 species
• Fins are bony, not fleshy
• Symmetrical and flexible caudal fin - allows
  teleost fishes to swim horizontally without using
  their paired fins for control
• Improvements in swimming ability resulted in
  decrease in armor
• More highly evolved jaw, allows for suction

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Anguilliformes - Eels

• Most live in shallow water, or hide near the
  bottom, in crevices
• Elongated shape, and lack pelvic fins
• Can swim backwards to easily get in and out of
  hiding places
• Larval form is distinct, and called a
  leptocephalus

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Clupeomorpha

• Include herrings, sardines, and anchovies
• More than 360 species
• Most are open-water, pelagic, schooling forms
• Feed on plankton, using a gill-straining
  apparatus
• Important commercial fisheries

Herring
Sardines
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Peruvian Anchoveta

• Peruvian Anchovy is the worlds largest fishery
• Oscillates strongly because of the climate

http//oregonstate.edu/instruct/fw465/sampson/anch
ovy/anchovy01.htm
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Salmon

• Anadromous - live as adults in the ocean, but
  return to their birthplace in rivers and streams
  to spawn

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Myctophidae - Lanternfishes
Lanternfish

• About 240 species
• Mesopelagic deep-sea fish
• Strong diel vertical migrators - come to the
  surface at night (make up a large part of the
  deep scattering layer)
• Bioluminescence and other adaptations for the
  deep sea

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Gadiformes - Cod, Haddocks, Hakes, etc.

• About 480 species
• Important commercial fisheries
• Most live near the sea floor

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Flying Fishes

• Mainly live in tropical and subtropical regions
• Pectoral fins are greatly enlarged, and caudal
  fin is modified into a forked tail fin with a
  slightly elongate lower lobe
• Gliding flights can last hundreds of meters

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Serranidae - Sea Basses and Groupers

• Contains 450 species, one of the largest fish
  families
• Great variability in size, from 3 cm. long, to
  the 3 m. long jewfish

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Tunas

• Highly adapted for a fast-swimming, pelagic life
• Some can swim over 70 mph!
• Can migrate large distances
• The giant bluefin tuna can get up to 4 m. and 500
  kg.

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Billfishes

• Marlins Sailfish
• Swordfish Spearfish
• - expanded premaxillary bone and other adaptations

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Flatfish - Pleuronectiformes

• More than 400 species
• Marked asymmetry
• Begin life as bilaterally symmetric pelagic
  fishes
• Includes the halibut, sole, turbot, flounder, etc.

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Ocean Sunfish - Mola Mola

• Temperate and tropical
• Lack a true tail
• Can get to be 2 m. long and weigh as much as 1000
  kg.

• Diet consists mainly of jellyfish
• Few natural predators, but are eaten by orcas
  and sea lions