External Anatomy

External Anatomy

Internal Anatomy

Internal Anatomy

Ichthyology is the branch of zoology devoted to the study of fishes Ichthyology is the branch of zoology devoted to the study of fishes. This includes skeletal fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). There are more fish species than the combined total of all other vertebrates: mammals, amphibians, reptiles and birds.

Modern ichthyology began in the 18th century, with the work of Peter Andreti and Carl Linnaeus Aristotle classified several hundred species of fishes. Less formal ichthyology was practiced by early hunter-gatherer societies.

Scales- Most fish have scales. In sharks the scales are called dermal denticles. They are tiny tooth-like structures in the skin. They give the shark's skin a smooth appearance that feels like sandpaper. Bony fish scales are made of bone and look like the shingles on a roof.

Placoid Scales Found in cartilaginous like: sharks and rays, Also called dermal denticles Placoid scales are structurally homologous with vertebrate teeth having a central pulp cavity supplied with blood Placoid scales cannot grow in size, more scales are added as the fish grows larger

Ctenoid Scales Name refers to comb-like ctenii, Found in the majority of bony fishes Scales grow with fish, results ring pattern, like tree rings, in some cases used to determine the age of a fish

Ganoid Scales Scales that are a non-overlapping or partially-overlapping scale, often rhomboidal in shape, with thick outer ganoine layer (enamel-like substance) Gars have these scales

Cycloid Scales Have a smooth texture, uniform with a smooth outer edge or margin Have numerous small comb likes spines Most common on fish with soft fin rays, Ex. salmon and carp

Fins Fins move, stabilize and protect a fish Fish may have paired fins (pectoral and pelvic fins), and unpaired fins (anal, caudal, and dorsal fins) Some fish do not have all of these fins, and their placement shows great variability The flexible fins of most bony fish have visible supporting rays and spines, Skeletal supports of cartilaginous fish fins are not visible, and fins are fairly stiff

Fins Cont. Give fish control over its movements by directing thrust, supplying lift and acting as brakes. A fish must control its pitch, yaw, and roll.

Caudal fin- provides thrust, and control the fishes direction Pectorals- act mostly as rudders and hydroplanes to control yaw and pitch, act as very important brakes by causing drag. Pelvic fins- mostly controls pitch Dorsal/anal- control roll

Breathing Oxygen enters the bloodstream at the gills Feathery structures found along the sides of the head Healthy fish gills are bright red due to the large amount of blood present. Gills of bony fish are usually covered by a bony plate called an operculum In sharks there are five to seven gill slits on the sides of the head

Gills

The eyes of most fish are well developed Most sharks have pupils that dilate and constrict and they have an eyelid that closes from the bottom upward Bony fish eyes lack pupils and eyelids

Shark eye

Boil and season to taste

Fish Mouths Sharks' mouths are located on the underside of the head. Bony fish mouth location varies Location and size of the mouth a good indicator of food the fish eats and where it lives. Fish with large mouths generally eat large food items (like another fish) whale shark eat very small organisms, strained from the water

Fish mouths continued Fish with small mouths eat small food items: small crustaceans or mollusks Fish with tiny mouths eat tiny things like zooplankton

Sacramento Blackfish

Native to the Sacramento and San Joaquin drainages as well as Clear Lake Ability to adapt to extreme environments including high water temperatures and salinities. Eats planktonic algae and zooplankton, including copepods, insect larvae, rotifers, and detritus

Copepods Rotifers

Mouth types A terminal mouth is located on the end of the head Fish with terminal mouths may chase and capture things, like the tuna, or pick at things, like the butterflyfish

Fish with up-pointing mouths have long lower jaws The mouth opening is toward the top of the head, Ex. tarpon, feeds near the surface

Fish with a sub-terminal mouth is on the underside of the head. Fish with this type of mouth usually feed on the bottom The bonefish has a sub-terminal mouth

Fish Body Shapes Fusiform, or streamlined, Ex. barracuda or jack are capable of swimming very fast, live in open water

Fish that are laterally compressed (flattened from side to side) usually do not swim rapidly, very maneuverable A flounder is a laterally compressed fish, lies on its side on the bottom

Depressed fish (flattened from top to bottom), like stingrays, live on the bottom

Eel-like fish have a snake-like body shape Ex. electric eel and moral eels, Capable of generating a 500volt electric shock through 28ft of still water

How do fish Swim? Most fish swim by pushing their bodies against the water sideways--first to one side, and then to the other, due to the way their bodies' muscles are built, limited to lateral movements

Anguilliform(ang-WIL-i-form) The way most eels, oarfish, and nurse sharks move The fish moves the entire body against the water in a snake-like fashion, this method is efficient Electric eels do not swim this way, but instead undulate only their fins to swim

Subcarangiform (SUB-ca-RANJ-i-form) This movement category includes salmon, trout, catfish, minnows, and cod Fish undulate most of their bodies, but leave their heads fairly still and concentrate most of the movement in the last two-thirds of their bodies

Carangiform (ca-RANJ-i-form) Drums, jacks, and mackerel, are very fast swimmers In streams, bass, crappie and sunfish use carangiform movement, throw their bodies into a shallow wave that increases in amplitude as it moves backward toward the tail, which snaps like a whip, leaves the head almost still The caudal peduncles (the part of the tail just before the caudal fin) are narrow and the tails are often forked, leading to more efficient movement

Thunniform (TOO-ni-form) This term used to describe the extremely fast and efficient movements of fishes like tuna, billfish, and lamnid sharks These fishes have very narrow caudal peduncles and large caudal fins that are lunate (look like the sliver of a waxing moon) Their tails are reinforced by keels, for strength and stability

Ostraciiform (oh-STRAY-kee-i-form) Many fishes are hampered by a boxy or globular shape Trunkfishes, cowfishes, and boxfishes have too much armoring to be able to flex their bodies These fishes scull their tails like oars

Boxfish Cowfish Trunkfish