What you are looking at is the fluke of a migrating Grey Whale (Eschrichtius robustus) off the coast of San Diego at Dana Point last week. A fluke with a recent bite out of it.
The image is courtesy of Dana Wharf Whale-Watching with a hat-tip to Peter Thomas Outdoors who brought it to our attention.
Click on the image for the full size.
What we noticed almost immediately were tell tale triangular marks of what might be a bite from the Great White shark.
Typically at this time of year it is the Killer Whale (Orcinus orca) that is the predator de jour of the Grey Whale, and tail bites are their signature.
This whale will survive, and probably be a bit wiser from it's latest encounter with a predator.
Our question of the day - which predator was it?