About minkes and Antarctic whales specifically:
Until recently a figure of 760,000 was the frequently-cited population estimate for minke whales in the Southern Ocean.

This figure was propagated by the Government of Japan, which wanted the world to believe that there was an abundance of minkes in the Antarctic. Derived from compiling separate estimates from different areas of the Antarctic, it was never officially sanctioned, but became generally accepted as a best-available estimate through constant repetition by Japan and the absence of any contrary data.

However, in 2000 the Scientific Committee of the International Whaling Commission (IWC) determined that, in fact, it had absolutely no idea how many minkes existed in the Antarctic and Southern Ocean. For one thing, it was now recognised that there were at least two, and perhaps three, separate species of minke whales in the region, and more recent studies were suggesting strongly that the actual number of minkes was much lower than the frequently-cited 760,000. In fact, in 2001, the Scientific Committee said that surveys were now suggesting the actual population figure might be as low as 300,000.

There are three theories to explain this decline: changes in the survey methods; minke whales leaving the area; and an actual decline in numbers. Most non-Japanese Antarctic scientists believe it is the third of these, perhaps triggered by diminished Antarctic sea ice as a result of global warming. (The formation and melting of sea ice plays a vital role in Antarctic marine ecosystems).

When we look at biomass - essentially, the total weight of all whales (a much better indicator than numbers) -- we see that 95% of the biomass of Antarctic whales was removed due to 20th century whaling, and has not recovered.

Additional threats to whales:
In addition to hunting, whales now also face a bewildering array of human-induced environmental threats. There is a growing body of evidence that shows climate change, ozone depletion, toxic and noise pollution, and prey depletion through over-fishing are already exerting negative impacts on whales. (For more information see Greenpeace report 'Whales in a Degraded Ocean').

The unknown:
Despite a great deal of study by legitimate scientific bodies, much is still unknown about many whale species, including minkes. Many species (like the minke) are highly migratory and spend much of their lives in remote parts of the world, making them more difficult to study.

ALSO, Because whales spend so much of their time under water, it is impossible to directly count the population - instead populations must be estimated. These estimates are based on a count of the whales sighted on each side of a survey vessel as it zigzags its way through a designated area of water. Since only a small percentage of the whales in any given population will be visible on the surface as the vessel passes, extrapolations are made from the number sighted to give an estimate for the entire region under study.

Thus all population estimates are based on sightings of a tiny fraction of the population. For example, a 1995 Norwegian minke whale survey sighted 29 whales in the eastern Barents Sea and this was extrapolated to a population estimate of 16,101 - over 500 times greater than the number of whales seen.

Finally, much is unknown about whale behaviour. For example, it has not been established whether minkes tend to be attracted to ships, or if they avoid them - although the former is beginning to be thought more likely. Naturally, such behaviour could considerably influence the number of whales seen during a sightings survey, and the population estimates which result.