It is a known fact that whales can swim underwater, to certain depths and distances, whereas today's odious whaling ships, and the harpoons they fire at our fine finned friends become rapidly ineffective at depths of even a few yards below sea level.
The main danger to whales is therefore the act
of surfacing for air. If we can eliminate this, or reduce it's frequency, we should be able to greatly improve the survival rates of the whale species in question.
Thusly, we shall create a string of Cousteauesque research stations, with very large moon pools, and air capacities. These research stations shall be located along... Err... Under known routes of cetacean migratory routes. Likewise, they shall be erected at distances whereby whales are known capable of traversing without surfacing for air.
In this way, the whales shall be able to traverse their global rounds far beneath the reach of the whalers. Morever, as these stations are clearly used for research, the whales can be named, cataloged, and their loss shall be duly noted, allowing various legal repercussions in the event that the whales are hunted.