Fish Phylum: Chordata Class Osteichthyes The Osteichthyes

Homework Read p152- 156 1. compare and contrast cycloid and ctenoid scales. 2. How do fish maintain bouyancy in water? 3. How does the body shape of a tuna and a flounder relate to their lifestyle? 4. What do fishes called grazers feed on? 5. Name two bony fish which are filter feeders who feed on plankton.

Homework Due Thursday Read p 157- 168 Answer the following in complete sentences 1. Where are spiracles located and what is their function? 2. What do chloride cells do? 3. Where are fish taste buds located? 4. Define Anadromous and give one species as an example. 5. Name two reproductive strategies fish use in mating.

Class: Osteichthyes the bony fishes - 98% of all fishes Distinguishing Characteristics Bony skeleton, thin overlapping scales Operculum Swim bladder Terminal mouth Most w/ fin rays

Huge Diversity in the Bony Fish Think adaptation! Think niche exploitation! Think staying alive, getting food, passing on more genes than the next guy!

What percentage of fish are bony fish? 2% 98% 89% 50%

External Structure As Chordates, fish have an incredible variety of characteristics. Most are covered with flat scales that fit into pockets in the skin and have a mucus coating. Some lack scales or have tiny scales. Scales may be cycloid, ganoid or ctenoid types. Some can be reabsorbed if food is scarce. Scales contain chromatophores that cause color changes for camouflage, mating - species recognition or when stressed. Iridocytes contain reflecting granules.

Cycloid Cycloid scales are thin and overlapping, permitting more flexibility.  Unlike ganoid scales, cycloid scales grow as the fish grows, and in some species, show annual growth rings.

Ctenoid Ctenoid Overlapping scales have tiny teeth called ctenii on the posterior edge that give them a rough texture.

Ganoid Most are diamond-shaped and connected by peg-and-socket joints. In sturgeons, the scales are greatly enlarged into armor plates along the sides and back, while in the bowfin the scales are greatly reduced in thickness to resemble cycloid scales

Coloration Chromatophores – w/ pigment – for color Iridophores – w/ crystals that result in structural colors (result when a special surface reflects only certain colors of light) Usually silver

Chromatophores

Iridophores

Coloration Warning coloration – Red Yellow Black or combinations of such colors Cryptic Coloration – used to camouflage Disruptive Coloration – used to confuse predators ---- ex. eye spots

Warning Coloration

Cryptic Coloration

Disruptive Coloration

Circulation: Closed Circulatory system 2 chambered heart, most ectothermic Tuna, barracuda and a few others maintain temperature higher (~10o) than environment so technically they are endothermic.

Vision: Poor to medium and usually only lateral Vision: Poor to medium and usually only lateral. The iris is not adjustable and lens protrudes through the pupil. Some fish can detect and generate weak electrical currents. This electro-perception is used to communicate in schooling, aids in migration, detecting and stunning prey.

Hearing: Aided by the lateral line, the swim bladder and the otoliths (located in the inner ear) detect movements and affect balance. Smell: Chemoreceptors are found on the mouth, lips, skin and fins. Most of brain is olfactory lobes use for smell to find food.

Designed for Speed Tuna are exquisitely designed for speed and can swim at 45 mph for long periods. NOAA They have a foldable dorsal fin that fits into a groove making it flush with the body to reduce drag when maneuvering.

The red blood cell count in tuna is equal to mammals The red blood cell count in tuna is equal to mammals. – more oxygen more energy!! Bluefin tuna and sailfish are the fastest fish at nearly at 70 mph.

Sun Fish – Slow Moving The largest bony fish is the Mola Mola (Sunfish). Molas eat plankton and can weigh 3000 pounds. They swim slowly and do not have a fusiform body shape, although it can be 11 ft. long.

Adaptations

Lionfish – Adaptation – poison spines

false eye Cryptic coloration: false eye on butterfly fish, kelp fish; counter-shading, (dark on dorsal surface and light on ventral); camouflage; aid in survival

Eye spot – confuses predators Adaptation – Eye spot – confuses predators Which side is the head on???

Surgeonfish - Scalpel for protection

Seahorse Seahorses are beautiful fishes with some remarkable adaptations including hard bony armour on the body, a prehensile tail (which can be used for holding on), binocular vision, excellent camouflage They have both an exo- and endo- skeleton.

Green Moray Eel Must constantly open and close their mouth to pump water through their gills to breathe

Coloring for camouflage

Adapted for flight ----Escape from predator

Mahi Mahi (Hawaiian Name) – fast notice homocercal caudal tail AKA: dorado or dolphin fish

Adaptation – Spine for protection The Cowfish

– Adaptations, Lure, large mouth expandable stomach Hairy Angler fish

Cells which allow for color change are called Colorforms Chromatophores Changelings Camofores

The only fish with both and exoskeleton and an endoskeleton is the Green Turtle Sea squirt Sea Horse Gastropod

Fish have a __ chambered heart 1 2 3 4

Adaptations Barbels- Feelers for detection Triggers, spines, poison – for protection and predation Schooling – for protection Coloration – for defense and predation

Schooling Schooling used by many smaller fish population to confuse predators not allowing them to focus on a single fish. Scientists believe that the coordination in the movement of a school of fish is due to chemical or electrical signals

Fin Shapes Homocercal vs. heterocercal tail High aspect vs low aspect tail

Caudal Fin Shape    Increasing the size of the caudal fin should increase speed; however, increasing size also increases drag          ii.      ASPECT RATIO gives information on caudal fin efficiency 1.      Aspect Ratio = (fin height)2 / fin area

Lunate

Round

Forked

Truncate

Homocercal Tail

Reproduction

Reproduction: sexual, mostly external fertilization called spawning Gonads - sac contains either sperm or eggs (roe). Sex reversal is common in reef fish and in deep water fish

3 Reproductive Strategies Only two used by Bony Fish Oviparous – lay eggs or egg cases Energy from yolk Viviparous – bear live young ------ Some Sharks and Rays Energy from mom Ovoviviparous – form “egg” but keep inside Energy from yolk, but inside mom

Oviparous Laying Eggs - spawning External fertilaization

Ovoviparous Eggs Lays Eggs….. And retain them in the body Mouth Brooders

Hermaphroditism male and female gonads still reproduce with other individuals more common in deep-sea fishes Why hermaphroditism? If you can’t find a female to mate with…….. why not just become a female? Or If you can’t be with the one you love…. love the one you’re with

Sex Reversal sea basses, groupers, parrotfishes, wrasses individual starts life as a male, changes into a female (or visa- versa) Why sex reversal? -In the deep ocean chance meetings of the same species are not wasted with gender issues

Bearing live young is referred to as being Oviparous Viviparous Omniviparous Ovoviparous

When the mother retains the fertilized egg it she referred to as being Oviparous Viviparous Omniviparous Ovoviparous

Egg layers are referred to as Viviparous Ovoviparous Omniviparous Ovipararous

How do fish "Breathe"?

Gills help regulate the salt/water balance called osmoregulation. Respiration: Water containing 02 flows over the gills in a different direction than blood so diffusion is maximized; muscles pump water through gills Gases from the blood and/or gulped air are used to adjust buoyancy in the swim bladder. Several gill arches supporting gill rakers and gill filaments are covered by a flap called the operculum. Gills help regulate the salt/water balance called osmoregulation. NOAA

“Breathing” Counter-current exchange for max diffusion efficiency Diffusion – the passive transport of gases (O2 and CO2) through a membrane Hemoglobin – carries oxy in blood Myoglobin – stores oxy in muscle

Gas exchange The way this taxon does gas exchange is through their gills. Fish take in water through their mouth that contains O2. The O2 goes into the bloodstream. The CO2 from the blood stream is released with the water through the fish’s gills.

Gill Structure Gill filaments – highly vascularised (it has a lot of blood vessels), large surface area Gill Arch – supports gills Gill Rakers (Filaments) – projections to keep food out of gills, or modified to catch food Lamellae – divisions of gill filaments, giving even more Surface area

Water Blood Water Blood Oxygen Exchange through diffusion

The Protein which stores Oxygen in the muscle tissue is called Hemoglobin Oxyglobin Myoglobin Triglobin

Blood and Water run ________ in the gill system more maximum efficiency. Concurrent Countercurrent None of the above

Structures which support the Gills are called Gill Rakers Gill Braces Gill Bones Gill Arches

The Gills are covered and protected by a flap of skin called the Operculum Gill Flap Epiglottis Gill Raker

The Gills extract ____ gas from the seawater Carbon Dioxide Water Salt Oxygen