Guys, it's really obvious that the highly irradiated scorched earth affected the genetic structure of whales living in the oceans.
These whales serendipitously grew specialized organs capable of generating dark matter through highly complicated protein manipulation of atoms on a molecular level. The whales gained the ability to not only control their buoyancy in water by generating this anti gravity matter within their bodies but also the ability to migrate towards food sources across the planet by floating on air currents. By using far fewer resources when traveling, they gained a competitive advantage over whales not able to float thereby enabling them to breed at higher rates.
Skywhales still mostly traveled over water and were rarely seen near land. Though many fishermen and people dwelling near the shores swore to have seen them, they were more or less viewed as a fairy tale creatures and imaginings of old salty sailors. This of course was mostly due to the remaining governments during the age of dust conspiring to cover up the existence of the skywhales.
Understanding the incredible strategic advantage of having a technology capable of making something as heavy as a whale float, the majority of whales that wandered close to shore were immediately harpooned down and scurried underground for secret government experiments. Eventually this lead scientists towards a rather simple method of production which though initially closely guarded, leaked out to the public when one of the governments failed.
Access to this ability to create dark matter is widely available now to any group capable of creating even a modest biochemical production facility; unfortunately the mass government hunting of skywhales made the species extinct.
Still though every now and then in a tavern, far away from civilization; you hear tales being spun by sky captains, probably gone crazy from the decades of moonshine, swearing to have seen one.
Most of them are known liars but every once and a while, a dull glow returns into the old war torn and weary eyes of a skyman as he tells his humble tale of majestic sea creatures emerging from the waves, water cascading off their hulking frames, jettisoning halos of vapor as they lift towards the heavens. Tales that make even the biggest skeptics pause and wonder, what if.
