Ok, so I did my homework. I got email from a librarian at the Hatfield Marine Science Center about cetacean stranding.
The concept that this is related to human activity, at this point, seems to be more hubris than anything.
The idea that we are somehow 'causing' this is refuted by any number of facts, notably the unchanging rate, but also supporting this is the issues of internal damage to organs in cetaceans being historical (to the eighteen hundreds).
You see, they used to try to *use* the parts (long ago, yano, whale-oil, whale-bone, etc.), so they noticed when they were damaged.
In fact, one of the more curious mass 'strandings' I read of concerned a pack of 'false killer whales' that 'stranded' on a beach with an old one who they protected from being 'saved' until he died, then they all left.
Now, one can't possibly project anthropomorphic thoughts onto another species, but just consider this one thought:
Perhaps, just perhaps, they were hoping for the 'old' humans on the shore. The ones that showed up immediately and put the elderly out of their despair (and then had a *big* feast).
For five hundred thousand years, that's been the 'norm'. We (sympathetic humans) are the 'difference' in this equation.
Perhaps even (in their theology) this 'stranding' is their attempt to get to heaven.
Yano, our tradition holds we'll get 'wings'.
Why shouldn't theirs think of getting legs?
Here's the info: