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Characteristics of Ray-Finned Fish ● Superclass Osteichthes and Class Actinopterygii are the “bony” or “ray-fin” fish. ● They are jawed fish with bone skeletons ● Most have a swim bladder and scales ● Most control buoyancy by adding or releasing gas to/from their swim bladder ● swim bladders exchange oxygen gas to and from blood circulation ● Many have a special organ called the gas gland the rete mirabile that take up gases from the bloodstream for the swim bladder ● This allows many species to hover nearly motionless in midwater Menu Previous Next

Characteristics of Ray-Finned Fish ● Most ray-finned fish reproduce externally. ● The female lays her eggs, usually in vast numbers that can reach millions in some cases ● The male immediately fertilizes the eggs ● Some species protect the eggs and juveniles, others leave larvae to fend for themselves as plankton ● The strategy here is to produce a vast number of offspring with only a few expected to survive to maturity. Contrast this with elasmobranchs Menu Previous Next

Menu Previous Next Basic Ray-Finned Fish Anatomy

▪ Dorsal fin – protects from rolling and assists in sudden turns and stops ▪ Caudal fin – used for propulsion ▪ Pelvic fins – paired, assist in going up or down through the water, turning sharply and stopping quickly ▪ Pectoral fins- paired, assist in maintaining depth, and flight in flying fish, and walking in lobe-finned fish such as anglerfish and mudskippers ▪ Anal fin - stabilizes Menu Previous Next

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Characteristics of Ray-Finned Fish ● Ray-finned fish have characteristics for life on the reef and for life in the open ocean: ● Ray-finned fish have lateral lines that detect water motion and vibrations ● Most open ocean and schooling fish are relatively similar in shape and coloration ● Fusiform shape - spindle form, broader at the head, and V-shaped tail. Ex. tuna ● Countershaded for concealment - dark on top, light on the bottom Menu Previous Next

Fast Fish Tuna adapted to the open ocean life. Menu Previous Next

https: //www. youtube. com/watch? v=c. VFq. ME-NW 9 s 4 min narrated on gas exchange http: //www. youtube. com/watch? v=bqplhl 0 My. Yg 2 min slides and definitions on gas exchange Menu Previous Next

● Ray-finned fish have adapted to many diverse bottom and reef habitats as well as midwater habitats. ● Survival strategies are likewise diverse concealment, armor and fast swimming ● For protection, reef and bottom species have far more diversity in color, shape, and size than midwater fish Angelfish Tall narrow bodies that can turn quickly and maneuver down into narrow cracks to hunt prey and escape predators Menu Previous Next

Founder Flat body for living concealed on the bottom Moray Eel Elongated, snake-like body for living in crevices and small caves Squirrel Fish A nocturnal fish with a red color that helps it remain concealed at night Menu Previous Next

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Special Attributes of Orders Clupeiformes and Gadiformes ● Two orders in class Actinopterygii have an important place in worldwide fisheries ● Order Clupeiformes which includes herrings, pilchards, sardines, and anchovies ● About one-quarter of all fish caught come from this order ● Order Gadiformes which includes cods, pollocks, haddock, whitings, and their relatives ● This order continues to produce about a sixth of the world’s fish catch ● Alaskan pollack, the haddock and whitings have become important fisheries ● Historically, worldwide fisheries have influenced politics and caused wars Menu Previous Next

Clupeiformes Anchovies Gadiformes Cod Gadiformes Haddock Gadiformes Pollock Menu Previous Next