Bony Fish

By: Brandon MonellaJoseph ThiryRyan Parrish

Bony Fish(General Information)

• There are 25000 species of modern Bony fish.• Most are characterized by a swim bladder (a lung), a

bone, bony scales and fin rays. • Bony fish make up 95% of all fishes. • Bony fish are divided into;

The lobefins (sarcopterygii) - 1. Coelacanths- 2. Fresh water lung fishRay Finned Fishes ( Actinopterygii ) - Containing all other bony fish species.

Coelacnths

• There are the links to the evolution of tetrapods.• They are characterized by paired fins that resemble limbs of

tetrapods.• Most live at depths of 150 to 200 meters.• Their habitat is rocky areas with deep subsurface gradients. • Their skeletons are mostly cartilage and bone but their

vertebrae is mostly cartilage. • They use a fat filled swim bladder to maintain bouyancy along

with a reduced skeleton.• They maintain high concentrations of urea in the blood to

remain isotonic.

Ray Finned Fish• Most numerous and dominant group of vertebrates in the ocean.• There are no common characteristics because there are so many characterized

forms. • Typically their fins are attached to their body by fins rays rather than fleshy lopes. • The Ray finned are broken in the two groups;

1. Subclass Chandrostei: > Contains primitive forms such as marine sturgeons.>They are armored and have tails like sharks.> They are primarily cartilage and ganoid scales.

2. Subclass Neoplerygii:>They have homocereal trails.>They have cycloid or ctenold scales and they are more vulnerable.

The structure of Bony fish gives them better control of their movements. They maneuver by using their pectoral and pelvic fins. Pectoral fins also stabilize the fish in water.

Body Shape• The characteristics of a fish generally are determined by its habitat.

Examples: 1. Fish that swim in open water anre generally agile and have a fusiform body

shape with a very high narrow tale. Stream like shape so they can be more agile and quick In the water. ( Tuna )

2. Fish which live In coral reefs or sea grass have a laterally compressed body so they can navigate more efficiently through their complex environment. ( Butterfly Fish )

3. Flounders of compressed bottom feeders have their flattened look because they are born normal but swim on their side so often that their eyes migrate to the top of them.

4. Fish like oster toadfish or angler fish have globular bodies and large pectoral fins which are usually enlarged to support the fish.

5. Moray eel type fish have elongated bodies t fit into tight spaces and reduce pelvic and pectoral fins.

Fish Coloration • Fish colors are two basic types, Pigments and structural

colors.Pigments: Pigments are colored compounds found in

chromatophores or irregularly shaped cells. Fish are able to alter their color by moving pigments between their central core. For example, the flounder can alter its color and pattern to match its exact environment. The control is under hormonal and nervous influence.

Structural Colors: Structural colors are produced by light reflecting off o the chromatophores which are called iridophores. They are colorless and cannot move in the cells. They make silver like or iridescent colors. Fish use coloring to advertise to predator that they are too venomous to eat. ( Lion Fish)

Locomotion in Bony Fishes

• Bony fish can move drifting with the current, burrowing, crawling on the bottom, gliding and swimming, the latter being the most common method. A bony fish moves by using its muscle to push against the water to move.

Respiration and Osmoregulation

> Bony fish use gills to extract oxygen for water. Their gills are composed of thing, highly vascularized rod like structures called gill filaments. > The blood and the water flow in separate directions which allows the blood to extract the oxygen to be absorbed into the blood. The water passing over the gills, constantly meets blood coming from the body with a lower oxygen and higher carbon dioxide concentration. Up to 80% of the oxygen in the incoming water can be extracted through this arrangement compared to when the water flow is parallel.

Nervous System and Senses

• Consist of brain, spinal cord; associated peripheral nerves and various sensory receptors.

• Olfaction; located in old factory pits, blind sacks that open to the external environment.

• Taste and hearing – taste receptors can be located on the surface of the head, jaw, mouth, tongue.

• Vision – They rely on vision more than sharks and rays do, they lack eye lids. Their eyes work like camera lenses they move forward and backwards to focus.

Buoyancy Regulation

• Most bony fishes with the acceptation with some pelagic species, bottom dwellers, and deep sea fishes, use a gas filled sack called a swim bladder to help them offset the density of their bodies and regulate buoyancy.

• By adjusting the amount of gas in the swim bladder a fish can remain at a given depth without any muscular movement and with minimal expenditure of energy.

• When the fish descends more gas must be added to the swim bladder. When the fish ascends it must remove gas from the swim bladder.

Cardiovascular System

• The cardiovascular system consists of a heart, veins, arteries and capillaries.

• Many active swimmers such as DA TUNA have a counter current arrangement to maintain body core temperature at two degrees, to ten degrees Celsius above the surrounding water.

• The veins containing relatively cool blood from the bodies pass close to in the opposite direction from the arteries contain warm blood coming from the body's core. Heat is then transferred from the blood in the arteries to the blood in the veins. In this way warm venous blood flows into the core of the body helping to maintain a higher internal temperature.

Adaptation to avoid Predators

• Some bony fish can swallow large amounts of air or water to inflate their bodies to inflate their size to deter potential predators. ( puffer Fish)

• Some bony fish can glide through the air. ( flying fish)• Some hide in other animals. ( the pearl fish )• Some have spiny tails to protect themselves. ( surgeon

fish ) • Some how powerful suckers to cling to rocks, which causes

fish to have a difficult time to pull them off of rocks. ( Cling Fish )

• Some have poisonous glands. ( Scorpion Fish )

Reproduction of Bony Fishes• Spawning fish release their eggs into the water column or deposit them

on the ocean floor. • Some species hide their eggs while some guard them until they hatch. • Pelagic spawners release eggs into the water, the male fertilizes them and

the eggs then drift with the water current. • Benthic Spawners;

– They have larger size eggs – Their numbers of their eggs are in more quantity than the pelagic spawners. – They are fertilized the same way as the pelagic spawners.

• Brood Hiders; They hide their eggs. • Guarders; They guard their eggs.• Bearers; They lay eggs in the males mouth, which the male incubates

until they hatch.

14 families of the bony fish have hermaphrodites.

Fish migration• Common and may occur daily or seasonally. • Daily migrations are usually associated with feeding and predator

avoidance. • Seasonal migrations are usually associated with changing

temperatures or feeding.• Some species migrations occur between freshwater and saltwater.• Herrings travel North then South following sea temperature variation. • Young mullets for example spend part of there time in freshwater or

estuaries but as adults they live mostly in the ocean.• Fish that move from freshwater to seawater are called catadromous

where as those that move from seas water to freshwater to spawn are anadromous