Nekton

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Nekton

• The nekton can swim against an ocean current and
  include most fish, sharks, whales, seals,
  dolphins, squid, etc.
• We will discuss the characteristics and
  adaptations of whales and fishes only.

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Whales

• Whales are marine mammals that breathe air, are
  warm-blooded, and feed milk to their young, just
  like humans
• There are two main groups of whales
• those with teeth
• those with baleen

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Toothed Whales

• These include dolphins, porpoises, killer whales,
  belugas, and sperm whales
• Sperm whales are the largest toothed whale. They
  can dive to great depths (1000m) and stay under
  for an hour. They feed mostly on squid.

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Baleen Whales

• Include all the largest species of whales - blue,
  fin, sei, humpback, minke, right
• They have 300-500 plates of baleen that hang from
  each side of the upper jaw instead of teeth,
  which they use to sieve krill out of the water
• An average humpback will eat 1-1.5 tons of krill
  per day

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Interesting Whale Facts

• Blue whales are the loudest animals on Earth!
  Their call reaches levels up to 188 dB. This
  whistle can be heard hundreds or perhaps even
  thousands of miles away. The blue whale is louder
  than a jet, which reaches only 140 decibels!

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Interesting Whale Facts

• Orcas are the fastest whales, reaching speeds of
  up to 48 km/hr
• Humpback whales sing the most complex songs
  only males sing
• Narwhals have the longest tooth 7-10 feet long

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Adaptations of Whales

• Streamlined bodies
• Powerful tail flukes
• Thick blubber layer to keep warm
• Twice as many red blood cells as other land
  mammals
• During dives - heart rate slows to conserve O2
• Water-tight seals on blowholes

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Video Mammals of the Sea
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Fish

• Fish are cold-blooded animals and possess gills
  for breathing and fins for swimming
• They live near the surface to the ocean depths,
  in warm water and icy water
• There are two main groups of fish
• Cartilage fish (sharks, skates and rays)
• Bony fish (tuna, cod, halibut, etc)

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Cartilage Fish

• Cartilage fish lack bones and have a skeleton
  made out of cartilage (the stuff that is in your
  nose)
• Cartilage fish are negatively buoyant will sink
  if they stop swimming
• Skates and rays have flattened bodies and
  wing-like fins

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Sharks

• Most sharks have several rows of teeth, but some
  are planktonic filter feeders (whale shark,
  basking shark)
• Predatory sharks have a keen sense of smell and
  are able to detect vibrations in the water to
  locate prey

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Sharks in Our Waters
Basking
Great White
Porbeagle
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Other Cartilage Fish
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Bony Fish

• Bony fish display the greatest diversity of all
  the vertebrates
• Possess air-filled swim bladders to aid in
  buoyancy
• 86 million tons of fish are taken each year for
  food

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Bony Fish, contd

• Sight and hearing are well-developed to obtain
  prey and avoid predators
• Bony Fish also have a lateral line system which
  is a series of pores along the side of the fish.
  It is used to detect vibrations in the water

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Some Unusual Bony Fish
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Adaptations of Fish

• Hydrodynamic torpedo shaped bodies
• Well-developed muscles for swimming
• Fins specialized for the particular fishs mode
  of life
• Countershading (dark on the dorsal side light on
  the ventral) aids in camouflage from prey and
  predators

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Label the Fish Parts
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Types of Caudal Fins
Slow
Fast
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Video Fish