Mark Brownlow / Sperm whale {Physeter macrocephalus} diving, tail fluke, Kaikoura, South Island, New Zealand

Jordi Chias / Humpback whale (Megaptera novaeangliae) fluke Antarctic Peninsula, Antarctica.

Jordi Chias / Humpback whale (Megaptera novaeangliae) diving, tail fluke, Antarctic Peninsula, Antarctica.

Shane Gross / Larval flounder (possibly Laeops Kitahara) in the open ocean at night off Anilao, Philippines.

Espen Bergersen / Humpback whales (Megaptera novaeangliae) showing tail fluke when they dive. Kvanangen, Troms, Norway. December

Espen Bergersen / Humpback whale (Megaptera novaeangliae) diving. In background a diving boat and 3 divers visible in the water. Kvanangen, Troms, Norway. November

Espen Bergersen / Sperm whale {Physeter macrocephalus} showint tail fluke as it dives. Photographed just before midnight. 22 nautical miles northwest of Andenes, Northern Norway. July

Espen Bergersen / Humpback whale (Megaptera novaeangliae) showing tail fluke as it dives. Kvanangen, Troms, Norway. November

Espen Bergersen / Killer whale / orca (Orcinus orca) splashing with tail fluke. Kvaloya, Troms, Norway October Sequence 4 of 7

Espen Bergersen / Humpback whale (Megaptera novaeangliae) showing tail fluke as it dives. Kvanangen, Troms, Norway. December

Nick Hawkins / North Atlantic right whale (Eubalaena glacialis) tail fluke, diving to feed in the Gulf of Saint Lawrence, Canada. Endangered species. July

Espen Bergersen / Aerial shot of a Humpback whale (Megaptera novaeangliae) diving and showing tail fluke, Troms, Norway, January.