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Marine Fishes. What is a fish??. Classic definition: -Any of numerous cold-blooded aquatic vertebrates of the superclass Pisces, characteristically having fins, gills, and a streamlined body and including specifically, and...
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What is a fish?? Classic definition: -Any of numerous cold-blooded aquatic vertebrates of the superclass Pisces, characteristically having fins, gills, and a streamlined body and including specifically, and... -Any of the class Osteichthyes, having a bony skeleton, and... -Any of the class Chondrichthyes, having a cartilaginous skeleton and including the sharks, rays, and skates. Although this is all accurate...we will find that fish are considerably MORE!!
Fish similarities... • Vertebrate ( chordate) • Gills • Fins • Scales
What is a fusiform body shape? • pointed leading edge • maximum depth 1/3 body length back from head • posterior taper • caudal fin interrupts ideal fusiform shape
Lamprey • Predatory/parasitic • Rasping teeth
Distinguishing Traits • cartilaginous skeleton • no swim bladder • heterocercal tail • scales and teeth • spiracles present with 5-7 gill slits • males have claspers, internal fertilization • teeth in rows, are constantly replaced
Sharks exhibit extreme variability in size, shape and abilities.
Nearly 850 spp. of sharks, 350 exhibit typical body morphology.
Cetorhinus maximus Carchariniformes – basking sharks, filter feeder
Mako Great White Isurus oxyrinchus Lamniformes - mackerel, mako, white sharks -carnivores Great White, Carcharodon carcharias
Skates and rays spend most of their lives near (on) the ocean floor eating molluscs, squid, and small fish. Yellow stingray, Urolophus jamaicensis
Like sharks, skates and rays come in many shapes and sizes.
Cycloid and Ctenoid Scales Found in bony fishes (the Teleostei). Overlapping = flexibility, over cosmoid or ganoid scales. Cycloid scales—smooth posterior margin. (Greek "cyclo“ or circle.)
Coloration is also veryimportant in fish.Here a stonefish “disappears”amid the coral background.Chromatophores, specializedpigment cells within itsskin provide protective coloration.
Disruptive Coloration (Camo!) • Disrupt the outline of the fish
Countershading • Being dark on top, light on bottom – Look like substrate from above – Look like water surface from below
Fish Locomotion Primary forces involved in fish swimming: Thrust - force that propels forward Drag - friction produced from passing an object through a medium Gravity – force from earth’s magnetic pull (partially counterbalanced by density of water) Lift - upward force that counteracts gravity
Fish Feeding - function • Herbivores • < 5% of all bony fishes, no cartilaginous fishes • browsers - selective - eat only the plant • grazers - less selective - include sediments • Detritivores • 5 - 10% of all species • feed on decomposing organic matter
Fish Feeding - function, cont. • Carnivores • zooplanktivores • suction feeding • ram feeding • benthic invertebrate feeders • graspers • pickers • sorters • crushers
Fish Feeding - function, cont. • Carnivores, cont. • fish feeders • active pursuit • stalking • ambushing • luring
Fish feeding behavior • Fish feeding behavior integrates morphology with perception to obtain food: • Search • --> Detection • --> Pursuit • --> Capture • --> Ingestion
Feeding behavior • Fish show versatility in prey choice and ingestion • Behavior tightly linked to morphology (co-evolution)
Lateral line also aids in navigation in close quarters. Damselfish, Chromis spp.