Upload
betty-helen-green
View
217
Download
4
Tags:
Embed Size (px)
Citation preview
Marine Fish
Intro to Fish
• Fish– The most common and diverse vertebrates in the
ocean– Evolved around 500 million years ago– 20,000 different species worldwide (freshwater &
marine)
Jawless Fish
• Superclass: Agnatha• Lack jaws and paired fins• Cyclostomic toothed mouth used to bore into
and suck blood from their victims• Most have a skeleton made of cartilage
Examples of Jawless FishSea Lamprey• Eel-like in appearance• Two dorsal fins • Can live in fresh or salt water • Parasitic as adult
Hagfish• Have 3 hearts• Can form an exterior cocoon from
slime that they produce• Can go up to 7 months without
eating
Jawless Fish Feeding
Bony Fish
• 95% of fish• Have a skeleton made of
bones• Protective covering of scales
that are easily removed• Skin secretes mucus to act
as a barrier for infection and to reduce friction
Breathing in Bony Fish• Fish breathe by letting water in through the mouth,
passing over the blood-filled gills
Locomotion in Fish• Fish that can swim are known as
nekton• Streamlined shape helps fish
swim faster• Temperature affects speed– Cold water = slower speed
Buoyancy in Fish
• Swim bladder: internal gas-filled organ that helps fish stay afloat when they are not swimming
Food-Gathering• Mouth shape & structure
depends on feeding method and prey– Straining plankton out of
water– Bottom dwellers have
vacuum like mouths to suck in food
– Beaklike mouths for nibbling on chunks of coral
– Strong flat teeth for crushing shells of invertebrates
– Predatory fish with large sharp teeth
Reproduction in Bony Fish• External fertilization and development• Spawning: the release of gametes during external
fertilization
Senses
• Lateral line senses vibrations from water • Detect low-frequency vibrations and
directional water flow• Function in distance perception• Fluid-filled canals open to water through tiny
pores