Chapter 7 Marine Fish

Phylum: Chordata Animals with a brain & spinal cord

Subphylum: Vertebrata Animals with a backbone or endoskeleton

Jawless Fish Class: Agnatha

Characteristics Jawless, sucking mouth, cylindrical, gill slits, meaty fins, cartilaginous, no air

Examples Lamprey Eel Hagfish

Cartilaginous Fish Class: Chondrichthyes

Characteristics Cartilaginous, gill slits, ventral mouth, meaty fins, no air, pointed scales

Bony Fish Class: Osteichthyes

Characteristics True bones, gill cover, terminal mouth, membranous fins, air sac, rounded scales

Operculum Gill cover in bony fish

Caudal Fin: Tail fin Dorsal Fin: Back fin Pectoral Fin: Side fin Pelvic Fin: Bottom fin

Fish Shape Activity dependent

Mouth Shape Diet dependent

Chromatophores Color pigment found in specialized cells in the skin of fish

Iridophores Crystal acting like tiny mirrors in the skin of fish making them look iridescent

Countershading Color pattern found in almost all fish where they are dark on the top & light on the bottom

Types of Coloration Cryptic: camouflage Warning: signals poison Disruptive: breaks silhouette

Myomeres Swimming muscles in fish

Locomotion: Bony Can hover Can swim backwards Can turn on a dime Can rise & fall

Locomotion: Cart. Cannot hover Cannot swim backwards Cannot turn on a dime Cannot rise & fall

Respiration in Fish Oxygen is exchanged by diffusion of dissolved oxygen gas into the gills

Gill Parts Gill Arch Gill Raker Gill Filament Lamella

Gill Arch Cartilaginous structure that supports the gills

Gill Rakers Forward protrusions that protect the gills

Gill Filaments Fleshy backward projections containing the working part of the gills

Lamellae Many rows of thin plates (increasing the surface area) where the diffusion takes place

Bony Gill Irrigation Can irrigate gills w/o moving Draw water through mouth Has operculum

Cart. Gill Irrigation Must swim to irrigate gills Draw water through spiracle or mouth Has gill slits

Bony Salt Regulation Osmoregulator Internal salinity = 14 %o Loses water through skin Drinks lots of water

Cart. Salt Regulation Osmoconformer Internal salinity = 35 %o Gains water through skin Need not drink water

Lateral Line Line of sense organs down each side of fish that detects vibrations

Ampullae of Lorenzini Sense organ behind the head of cartilaginous fish that detect electric fields

Fish Behavior Territoriality Schooling Migrating

Territoriality Protecting territory Pelagic Fish: not much Benthic Fish: are territorial

Schooling Traveling in large groups Protection Increased efficiency

Migrating Seasonally moving from place to place Warm mating grounds Cold feeding grounds

Anadromous Mating in fresh water and living in sea water Salmon

Catadromous Mating in sea water and living in fresh water American eel

Vertical Migration Migrating during the day to the mesopelagic zone for safety & back to the surface at night to feed

Reproductive Behavior

Spawning External fertilization Bony fish

Hermaphrodites Able to fertilize their own eggs

Oviparous Lays eggs

Viviparous Live birth

Ovoviviparous Lays eggs, but still has live birth

Copulation Internal fertilization Sharks & Rays