(Photo found here)

The Port Jackson shark (Heterodontus portusjacksoni) is a nocturnal, oviparous (see this post) type of bullhead shark of the family Heterodontidae, found in the coastal region of southern Australia, including the waters off Port Jackson. It has a large head with prominent forehead ridges and dark brown harness-like markings on a lighter grey-brown body. Port Jackson sharks can grow up to 5.5 ft. The Port Jackson shark is a migratory species, traveling south in the summer and returning north to breed in the winter months. They feed on hard-shelled mollusks, crustaceans, sea urchins, and fish. Port Jackson Sharks are quite distinctive blunt headed-sharks that lay eggs. Port Jackson Sharks have harness-like markings which cross the eyes, run along the back to the first dorsal fin, then cross the side of the body. This pattern makes it very easy to identify this species.

(Source)

kari-shma:First Contact (by CMGW Photography)

Manatee (see this post)

This is Isidella tentaculum, a type ofBamboo coral of thefamily Isididae. A family offamily of mostly deep-sea coral of the phylum Cnidaria, class Anthozoa, It is a commonly recognized inhabitant of the deep sea, due to the clearly articulated skeletons of the species. Deep water coral species such as this are especially affected by the practice of bottom trawling. These organisms may be an important environmental indicator in the study of long term climate change, as some specimens of bamboo coral have been discovered that are 4,000 years old. Relatively little is known about bamboo coral. The skeletons of bamboo coral are made up of calcium carbonate in the form of tree-like branches alternating with joint-like nodes or axes composed of gorgonin protein. The alternation of the bony structures with the smaller gorgonin parts give the bamboo coral a finger-like appearance similar to that of the bamboo plant on land. For more on corals see these two previous posts.

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(Photo found here)

Southern bluefin tunas (Thunnus maccoyii) are a very large species commonly caught by Indonesian and Japanese commercial long-liners in the Indian Ocean, their spawning ground. If a southern bluefin tuna reaches adulthood (when they are about 12 years old) before they’re caught, they can reach 8.2 ft and weigh up to 882 lbs. It is among the larger bony fishes.

(Source)

oceanic-adventures:shark! by Modest Janicki (Modest and Jill) on Flickr.

Great white shark

(Source of photo here) Juvenile tiger shark, Galeocerdo cuvier, Bahamas (Atlantic) (see this post)