Shark

A Zaralok, a giant armoured shark from the planet Shakara. (VG: Shadows of the Vashta Nerada)

Sharks were a type of predatory fish.

Earth Sharks

In Atlantis, the Second Doctor, Ben, Polly and Jamie were nearly fed to sharks as a sacrifice to Amdo. (DW: The Underwater Menace)

In the 1970s, the Australian branch of UNIT discovered a fragment of Brokk's spaceship in the belly of a shark. (MA: The Eye of the Giant)

Samantha Jones was afraid of sharks after watching the film Jaws 2. (EDA: The Taint)

Sharks of Other Planets

• On an unnamed planet, the First Doctor, John and Gillian helped a race of intelligent frogs catch a shark that was trying to eat them. (TVC: Shark Bait)
• Aaglon sharks were creatures native to Olleril. (NA: Tragedy Day)
• The Pescatons apparently evolved from sharks or a shark-like species. (Doctor Who and the Pescatons)
• The planet Philjax III was home to a species reminiscent of sharks. (DWBIT: #9)
• The Empetniks were a shark-like species native to the planet Senkus Sha. (DWBIT: #27)
• On the planet where Sardicktown was found, there were flying sharks which lived in the crystalline fog. (DW: A Christmas Carol)
• In the 23rd century, a giant armoured shark called a Zaralok was transported to Earth and attacked the aquatic reseearch station Poseidon 8, before it was sent back by the Eleventh Doctor and Amy Pond. (VG: Shadows of the Vashta Nerada)

Other References

• The Ockorans designed their suits and named their soldiers (Selachians) after sharks to intimidate their enemies. (PDA: The Murder Game, The Final Sanction)
• The Roboforms and Sycorax were compared to pilot fish and sharks, with the Roboforms following the more powerful Sycorax. (DW: The Christmas Invasion)