How do cartilaginous fish stay afloat?

Answer 1

Bony fishes achieve buoyancy through an air filled sac called a swim bladder. The bladder controls the fish's buoyancy by varying the gas pressure inside the fish's body to allow it to sink or rise in the water.

Chondrichthys, or cartilaginous fishes (sharks, skates, rays) achieve buoyancy in other ways because they do not have swim bladders. They do this 3 ways:

1. Store low-density compounds in the body. They store various lipids in throughout their bodies ,which have lower densities than seawater. Squalene is one lipid that is stored in the liver of sharks.

2. Reduction of dense tissues. Chondrichthys do not have replaced bones with cartilage, which helps them reduce their weight in the water. Cartilage is 1/2 as dense as bone. They also reduce muscle mass and protein content. They also increase water content of tissues .

3. Dynamic lift. Sharks can generate lift by their swimming motion. They have a heterocercal tail with a larger dorsal lobe than the ventral lobe. This tail generates lift on the posterior end of the fish, but pushes the anterior end down. This is corrected by having large pectoral fins. This positive attack angle generates head lift. The head of a shark is also flattened dorsoventrally and counteracts the tendency for the tail to push the head downward.

The disadvantage of the Chondrichthys methods of buoyancy is that it is difficult for them to adjust their buoyancy and low density lipids are energetically expensive to make. Dynamic lift requires constant forward motion. They must keep swimming, which can also cost a lot of energy.

Answer 2

Sharks for example that do not posess a swim bladder for buoyancy like many bony fishes have, must depend upon their livers. The liver contains squalene which is an organic compound that is lighter than water. The liver takes up 30% of the sharks body mass, but it is limited in use. The shark basically has to keep moving to live with it's fins. Some sharks though store air in their stomachs acting as a swim bladder to stay motionless. Also some sharks can pump water across their gills to allow them to rest at the bottom.

Answer 3

Fish manage to stay upright because of their equally distributed body mass and the hydrodynamics of their fins;also partially in the aero dynamics of their bulet-shaped or flat bodies. Whereas making it easier tobalance and glide through thewater and currant.^^

Answer 4

Cartilaginous fish stay afloat by regulating their buoyancy using their liver, which is rich in oils that are less dense than water. They also have a cartilaginous skeleton that is lighter than a bony skeleton, helping them to remain buoyant in the water. Additionally, their streamlined body shape reduces drag, allowing them to move more efficiently through the water.

Answer 5

A fish is buoyant because it has a blader.

Answer 6

The fins of the fish help the fish stay upright in the water, as it is swimming.

Answer 7

their bladder.

Answer 8

Pizza?