There are a few important characters: an even longer back, a tiny dorsal fin set very far back, and mottled blue-gray color.
Here's another example from later in the day:
These Blue Whales (Balaenoptera musculus) were remarkably close to land. Rick estimated we were about 1.5 miles off Bodega Head, but I wondered if the whales were even closer than that at times. Amazing! If they stay in this area, it's a great opportunity to see Blue Whales from shore (e.g., from the State Parks outer parking lot on the southern end of Bodega Head).
It was foggy in the morning, and very still (no wind), so we could hear the powerful blows of these whales when they surfaced:
The Blue Whales raised their flukes a couple of times. I only managed a so-so picture of the flukes, but it's still helpful to see the distinctive shape (quite different than the rough-edged flukes of a humpback and the rounded flukes of a Gray Whale):
I posted about Blue Whales a few years ago on 31 August 2013 — for more pictures and some information about Blue Whales, click here.
P.S. It's hard to visualize the size of a Blue Whale (the largest animal that ever lived on Earth). Perhaps you've heard about the size of a Blue Whale's heart? Its dimensions are similar to a VW Bug, although the Blue Whale's heart is shorter in length: