Japan is the only nation that still exploits Antarctic seas, now an internationally recognized sanctuary for whales.
The sanctuary is an artifact of years of bad faith at the IWC.
The IWC was originally created because of the competing interests of whaling nations in the Antarctic hunting grounds.
During the 1960's and 1970's, although it took too long, various whale stocks that had been over-exploited were protected internationally. Whaling nations accepted these protections (although the USSR allowed illegal whaling to continue for some years).
In 1982, the "moratorium" was established, and yet it was in the main a duplication of the previous conservation measures adopted in the 1960's and 1970's. What the 1982 moratorium did acheive was ban the hunting of even the Antartic minke whale, which by 1990 was recognised by the IWC to number in the hundreds of thousands. The species was by no means over-exploited, and yet the moratorium banned further exploitation despite catch levels at the time being around 6,000 ~ 8,000 a year. Whether these levels of catch would have been sustainable over the long term or not is debatable, but with some hundreds of thousands of minke whales, they certainly weren't about to result in the sudden collapse of the minke stock like other whale stocks before them. Nonetheless, Japan eventually agreed to accept the moratorium, albeit while starting a research program to obtain a source of biological data on the population.
Roll around 1994, the IWC had received new advice that it was now possible to set sustainable catch limits for minke whales in the Antarctic. Whaling nations were willing to accept this new catch limits setting procedure, which was likely to produce lower quotas than those prior to the moratorium. At this point the IWC should have abolished the moratorium in recognition of this development, and permit catches for minke whales once again.
What the IWC did instead was establish the Southern Ocean Sanctuary, completely covering over the entire Antarctic hunting grounds that the IWC was originally established to co-ordinate exploitation within, and additionally demand that whaling nations accept new sets of regulations on whaling operations that would make whaling operations prohibitively expensive, so that even if legal, they would be impossible.
This sanctuary is certainly not "internationally recognized ". Many nations have explicitly stated that they think it's establishment was illegal.