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… Sexesare 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 externalfertilization; and, oviparity, viviparity, and ovoviviparity strategies areall utilized… What may be the advantages and disadvantages of each?

Broadcast Spawning

Basic classification ofvertebrates 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 fishesClass 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 welldeveloped jaws and teeth;

Typically have a ventral mouth;

and, have rough, sandpaper-likeskin 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 Feedin

g Frenzy• Air Jaws: Sharks of South Africa: Filming Air J

aws

Shark Mating

• Discovery Channel Videos:• The Ultimate Guide to Sharks: Shark Mating• The Ultimate Guide to Sharks: Shark Birth an

d Maturation• Sibling cannibalism

Skates vs. Rays• Different Orders• Reproduction

– 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