Reading Assignment:

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Reading Assignment

• Chapter 3 in Moyle Cech
• Respiration

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Effects of Properties of Water on Living Organisms

• Density Buoyancy
• Archimedes Principle--when an object is immersed
  in a fluid, an upward force acts on it, equal to
  the weight of the fluid it displaces

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air
Archimedes Principle
positive buoyancy
positive buoyancy
positive buoyancy
water
neutral buoyancy
Fish?
negative buoyancy
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Densities of Biological Substances
end
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• Slight negative buoyancy--densities of most
  aquatic organisms are close to that of water
  (usually slightly more dense)
• fish densities--1.06-1.09 g/cm3

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Support

• Aquatic organisms are well supported due to
  density similarities between water and aquatic
  organisms
• Effects--reduced energy expenditure
• reduction or lack of support tissues

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Streamlined shapes

• Active fish tend to be streamlined due to high
  energy required for locomotion in water

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end
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Ecological Groups of Fishes

• Six general categories
• body shape
• habitat
• general life style
• Clues to lifestyle
• Doesnt fit all fishes

• Rover predators
• Lie-in-wait predators
• Surface oriented fishes
• Bottom fishes
• Deep-bodied fishes
• Eel-like fishes

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1. Rover Predators--moving hunters

• Terminal mouth
• Fins evenly placed (maneuverability)
• stream-lined

brassy minnow
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Ex Salmonidae
brook trout
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Ex Percidae
walleye
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Ex Centrarchidae (basses only)
largemouth bass
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end
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2. Lie-in-Wait predator (piscivores)

• Terminal mouth large w needle-like teeth
• Stream-lined often elongated and thin
• Head flattened

northern pike
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Lie-in-Wait predator (continued)

• Caudal fin large
• Dorsal and anal fins placed posteriorly
• Cryptic coloration

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Esocidae-pikes, pickerel, muskie
muskellunge
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Lepisosteidae - gars
longnose gar
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needlefish
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Sphraenidae -- barracuda
longnose gar
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end
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3. Surface-Oriented fishes

• Often small
• Upward tending mouth (superior or superterminal)
• Dorsoventrally flattened head
• Adapted to surface life
• Poeciliidae-live bearers

guppies
mollies
mosquitofish
Gambusia
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Four-eyed fish
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Cyprinodontidae-pupfish, killifish
banded killifish
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Other surface oriented fishes

• betas
• archerfish

Gambusia
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end
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4. Bottom fishes (benthic)

• Swimbladder reduced or absent
• flattened dorsoventrally (depressed)

Atlantic halibut
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Bottom fishes continued

• Specialized structures
• sensory structures barbels, fin rays
• modified fins (darters, clingfishes)

barbels
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sea robin
sea robin
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Pleuronectiformes-flatfishes

• flounders
• soles
• tonguefish

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hog choker
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Acipenseridae--sturgeons
lake sturgeon
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Skates rays
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5. Deep-bodied fishes Laterally flattened
(compressed)

• Dorsal and anal fins long
• Pectoral fins high on body
• Pelvic fins thoracic
• Mouth protrusible
• Fin spines

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Centrarchidae-crappies sunfishes
bluegill
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end
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6. Eel-like fishes--elongated bodies

• Paired fins reduced or absent
• Dorsal and anal fins long
• Scales small or absent
• Flexible bodies
• Adapted for small crevices

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American eel
snake eel
slime eel
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moray eel
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end
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end
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Field Trip to Forest River

• Collect and view fishes from various
  habitatsriffles, pools
• Hone your skill with a seine
• Not required, but fun and informative
• Bring a friend if you like

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Field Trip Details

• Saturday 28 September 900-200
• Meet at 900 in Starcher Hall parking lot
• Bring drinks and a sack lunch if you wish
• Consider whether you would be willing to drive
  (45 mi)
• We will ask who plans to attend during next
  weeks lab
• Ryan and I will drive--We also will ask for
  volunteer drivers

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Field Trip Details

• Wear old clothesbe prepared for mud, bushes, and
  mosquitoes plan to get wet
• Bring waders or rubber boots if you have them
• If its warm you can wear shorts and old sneakers
  for wading
• Bring binoculars and field guides if you wish