Barbels – Atlantic Sturgeon

Marine Fishes – Sensory System (cont.) Finally, many fish have a lateral line that allows them to sense vibrations in the water…

Marine Fishes – Reproductive System A few species of fishes are hermaphroditic, but most have separate sexes… Sexes are not always definitive though, with many species exhibiting sex reversal. What are the advantages of each of these strategies? Depending on the species of the fishes, they all have a wide range of behaviors associated with mating. Also, different species exhibit internal versus external fertilization; and, oviparity, viviparity, and ovoviviparity strategies are all utilized… What may be the advantages and disadvantages of each?

Broadcast Spawning

Basic classification of vertebrates and fishes: By the way: Fish – single individual or more than one individual of the same species. Fishes – more than one kind of fish.

Cartilaginous fishes Class Chondrichthyes

Marine Fishes Class Chondrichthyes – Cartilaginous fishes; with about 1000 different species, they include the different species of sharks, rays, skates, and ratfish. Cartilaginous fishes have well developed jaws and teeth; Typically have a ventral mouth; and, have rough, sandpaper-like skin because of tiny scales… In fact, their teeth are simply modified scales!!

Senses

Senses

types of caudal fin : (A) - Heterocercal, (B) - Protocercal, (C) - Homocercal, (D) - Diphycercal

Shark Diet Discovery Channel Videos: The Ultimate Guide to Sharks: Shark Diet Air Jaws: Sharks of South Africa: Shark Feeding Frenzy Air Jaws: Sharks of South Africa: Filming Air Jaws

Shark Mating Discovery Channel Videos: The Ultimate Guide to Sharks: Shark Mating The Ultimate Guide to Sharks: Shark Birth and Maturation Sibling cannibalism

Skates vs. Rays Different Orders Reproduction Tooth Structure Rays are viviparous (live bearing) while skates are oviparous (egg laying), releasing their eggs in rectangular cases sometimes called "mermaid´s purses". Tooth Structure Although skates may have small teeth, those of rays are plate-like and adapted for crushing prey.  Morphology Skates normally have prominent dorsal fins while those of rays are absent or reduced in rays. Although a few electric rays are capable of delivering a powerful electric shock and some sting rays have large, barbed stingers, in general, these docile animals pose no real threat to swimmers and divers.

Skate