Elasmobranchs vs. Teleosts

Attribute	Elasmobranchs	Teleosts
Class	Chondrichthyes	Actinopterygii
Skeleton	Cartilaginous	Bony
Gills	5-7 pairs	4 pairs
Fins	Dorsal, pectoral, pelvic, anal, caudal	Dorsal, pectoral, pelvic, anal, caudal
Reproduction	Mostly viviparous	Mostly oviparous

Physical Characteristics

Elasmobranchs, which include sharks, rays, and skates, are cartilaginous fish with skeletons made of cartilage rather than bone. They have five to seven gill slits on each side of their bodies and lack a swim bladder. Teleosts, on the other hand, are bony fish with skeletons made of bone. They typically have a swim bladder that helps them control their buoyancy. Teleosts also have a single gill cover on each side of their bodies.

Habitat

Elasmobranchs are found in a wide range of marine habitats, from shallow coastal waters to the deep sea. They are often associated with coral reefs, rocky bottoms, and sandy flats. Teleosts, on the other hand, are the most diverse group of fish and can be found in almost every aquatic environment, including freshwater, saltwater, and brackish water. They inhabit rivers, lakes, oceans, and estuaries.

Reproduction

Elasmobranchs reproduce using a variety of methods, including oviparity (laying eggs), viviparity (giving birth to live young), and ovoviviparity (eggs hatch inside the female's body). Some species of sharks have long gestation periods and give birth to relatively few offspring. Teleosts, on the other hand, typically reproduce through external fertilization, where the female releases eggs and the male fertilizes them outside of the body. They can produce large numbers of eggs in a single spawning event.

Feeding Behavior

Elasmobranchs are carnivorous predators that feed on a variety of prey, including fish, crustaceans, and mollusks. They have sharp teeth and powerful jaws that allow them to capture and consume their prey. Teleosts, on the other hand, have a wide range of feeding behaviors, including herbivory, omnivory, and carnivory. Some teleosts are filter feeders that consume plankton, while others are predators that hunt for larger prey.

Sensory Systems

Elasmobranchs have a highly developed sensory system that includes keen senses of smell, sight, and electroreception. They use their lateral line system to detect vibrations in the water and locate prey. Teleosts, on the other hand, also have well-developed sensory systems, including eyesight, taste, and the lateral line system. Some teleosts can detect changes in water pressure and temperature to navigate their environment.

Behavior

Elasmobranchs are known for their solitary and territorial behavior, with some species exhibiting migratory patterns to follow prey or find suitable breeding grounds. They are also known for their ability to detect and respond to changes in their environment. Teleosts, on the other hand, exhibit a wide range of social behaviors, including schooling, shoaling, and territoriality. Some teleosts form complex social hierarchies within their groups.

Conservation Status

Elasmobranchs are facing increasing threats from overfishing, bycatch, habitat destruction, and climate change. Many species of sharks and rays are considered vulnerable, endangered, or critically endangered. Teleosts, on the other hand, are also impacted by overfishing and habitat degradation, but their diverse range of species means that some populations are more resilient to these threats. Conservation efforts are underway to protect both elasmobranchs and teleosts from further decline.