Here is a ranking of the world's smallest whale populations and some facts about the impact of whaling upon them:

1. NORTH ATLANTIC RIGHT WHALE

-- Population: Approximately 350. Endangered.*

-- Found off the US East Coast and Canada, the slow swimmers were targeted for centuries for their abundant oil. In 1935 it became the first whale protected from commercial hunting.

2. BLUE WHALE

-- Population: About 5,000. Endangered.

-- The world's largest animal, weighing up to 100 tonnes and growing to 100 feet (30 metres). Distributed throughout the world's oceans.

-- Hunted to near extinction, numbers shrank from 250,000 to around 1,000 by 1950s. Now rebounding since 1960s whaling ban.

3. BOWHEAD WHALE

-- Population: About 8,000. Low extinction risk.

-- Found in the Arctic, where its 70 cm thick blubber helps it survive icy waters.

-- Hunted for its oil and baleen, or "whale bone", from the 17th century to the early 1900s; protected since 1946.

4. HUMPBACK WHALE:

-- Population: Between 10,000 to 20,000. Vulnerable.

-- Humpbacks live in all the world's oceans. Known for their agility and acrobatics, they also "sing" for up to 30 minutes.

-- Japan dropped plans to hunt 50 humpbacks this year after strong international protests.

5. GRAY WHALE

-- Population: 25,000. Low extinction risk.

-- Found mainly in the northeast Pacific. Gray whales are already extinct in the North Atlantic. The 100 or so Western Pacific gray whales are classed as critically endangered.

-- Decimated by hunters in the 1850s. International Whaling Commission protection has seen numbers rebound since the 1940s.

* Conservation status classified according to the IUCN.

Sources: Reuters, World Wildlife Fund (http://www.worldwildlife.org), World Conservation Union (http://www.iucnredlist.org), International Whaling Commission (http://www.iwcoffice.org/index.htm)